People v. Mehlberg (249 Ill. App. 3d 499, 1993)

JUSTICE WELCH

delivered the opinion of the court:

Defendant, Donald Mehlberg, was convicted on August 31, 1990, of aggravated criminal sexual assault and was sentenced on October 5, 1990, by the circuit court of Montgomery County to 30 years in the Department of Corrections. Defendant raises the following issues for review:

(1) whether the trial court erred in admitting evidence that DNA found in semen in the victim’s panties matched the DNA found in a sample of defendant’s blood;

(2) whether defendant was deprived of his constitutional right to effective assistance of counsel when counsel elicited, during cross-examination of the State’s expert witnesses, statistical evidence of the probability of a match occurring between the DNA found in the victim’s panties and the DNA found in the blood sample taken from defendant;

(3) whether defendant was deprived of his constitutional right to effective assistance of counsel because counsel failed to call defense expert witnesses to challenge the reliability of DNA identification and the statistical probability of another individual having defendant’s DNA pattern;

(4) whether the error in admitting the DNA identification evidence could be considered harmless where the State could not have proved defendant guilty of aggravated criminal sexual assault beyond a reasonable doubt without said evidence; and

(5) whether defendant was denied a fair trial by the trial court’s denial of defendant’s motion for a mistrial made after one of the prospective jurors announced to the voir dire panel that she was familiar with defendant through his files in the probation office, giving the inference to the panel that defendant had a prior record.

We affirm the judgment of defendant’s conviction and sentence.

The evidence adduced at trial indicates that the victim and her husband were neighbors of defendant’s parents in Litchfield, Illinois, since December 1988. Defendant was living with his parents at the time of the alleged assault in July 1989. The victim knew defendant from high school but had not spoken with him in nine years. The victim had seen her husband speaking with defendant outside of the home prior to the alleged July 16, 1989, incident, but defendant had never been invited into the victim’s home.

The victim’s husband is employed in St. Louis, Missouri, and in July 1989 was working either the 6 a.m. to 6 p.m. shift or the 6 p.m. to 6 a.m. shift, five to six days per week. She and her husband own two vehicles, a Camaro and a truck, and she drives the Camaro most of the time.

Photographs of the victim’s house were admitted into evidence. These photographs showed the proximity of the victim’s house to the house owned by defendant’s parents and showed that the entire backyard of the victim’s house is fenced. A diagram of the victim’s house was also admitted into evidence. The victim testified that there is a front door on the house and a kitchen door at the landing leading right to the basement and left into the garage. The kitchen door has a hook-type lock on it which must be locked from the inside. There is another door leading from the landing to the garage which has a deadbolt-type lock; however, a hole had been drilled into the door so that a person could stick his finger in and unlock the deadbolt lock. There is also a door in the back of the garage which leads into the fenced back yard. The victim’s car is usually parked on the right-hand side of the garage and the garage-door handle locks by turning the knob.

The victim testified that she had been home during the evening of July 15, 1989, but had left home around 11:15 p.m. to retrieve her daughter Amber from a cookout at a friend’s house. She exited the house by the front door and remembered locking that door when she left. The victim testified, however, that the kitchen door to the landing was not locked, nor was the landing door leading to the garage or the door leading from the garage into the back yard. She recalled that the garage door was down but did not think that it was locked. The victim saw the defendant, in the front of her house, walking across the sidewalk towards his parents’ home, and she waved at him as she walked to the driveway to get into her car.

The victim’s husband was also at the cookout that evening but did not leave when the victim came to pick up Amber. The victim and her daughter arrived home around midnight. They went into the living room, and the victim put a movie into the VCR for Amber to watch before she fell asleep. The victim then locked the front door and the kitchen door to the landing. The victim went to the bedroom to take off her shorts, grabbed a blanket, and went to the bathroom. She then lay down on the couch in the living room to watch some more television but set the VCR to turn off at 3 a.m. in case she fell asleep. The victim was wearing a white T-shirt, underwear, and socks. There was a panty liner in her underwear because she was just finishing her period.

The victim fell asleep on the couch with the television on but was awakened when someone placed a hand across her mouth and a knife at her throat. She heard a voice say, “Don’t scream or anything or it will be your little girl’s ass.” She could not see who the perpetrator was because he was behind her with the knife on her throat. The night light between the two chairs was the only light on in the living room. Out of the comer of her eye the victim could see that the perpetrator was wearing a white mask.

The perpetrator told the victim to get off the couch and go through the,, kitchen. He unlocked the kitchen door and pushed her into the garage. There were no lights on in the kitchen, the landing area, or the garage. The perpetrator told the victim to take off her underwear, made her bend over, and had intercourse with her from behind. The perpetrator told her that it was not working and bent her head down so that she would have oral sex with him. She pleaded with the perpetrator not to make her do this act. The perpetrator told the victim to turn back around and started having intercourse with her again.

The perpetrator told her not to call the police because he would call her husband’s employer and tell them that the victim’s husband had been convicted of a felony about six years ago. He asked her if her husband would lose his job if his employer knew this, and she said yes. The perpetrator used her husband’s first name when he made this statement. Defendant and the State stipulated that, at a time approximately six years prior to the alleged aggravated criminal sexual assault in this case, defendant and the victim’s husband resided together for a period of months in the same residential facility.

The perpetrator also told her that he had been in her house before and that he knew when her husband left for work and when he came home. The perpetrator told her that her husband had hired him to watch her while he was at work. He said that he knew she had left Amber by herself when she left the house earlier that evening.

When she heard the garage door go up and down the victim grabbed her underwear and ran into the house. She called her sister and attempted to locate her husband. The victim’s sister drove her to the hospital. The victim admitted on cross-examination that her husband occasionally brought some of his friends to the house to socialize, but defendant was not one of those friends.

Vonna Wessell testified that she is a registered nurse employed by St. Francis Hospital in Litchfield, Illinois. Nurse Wessell was on duty at 3:45 a.m. on July 16, 1989, when the victim arrived at the emergency room stating that she had been sexually assaulted. St. Francis Hospital follows a certain procedure with sexual assault victims: they first make certain that the police have been called, they explain the evidence-kit procedure to the patient, then they take the clothing worn by the victim and obtain samples from the patient. These samples include vaginal and rectal swabs and smears, saliva samples, fingernail scrapings, head- and pubic-hair samples, and combings.

Nurse Wessell took a T-shirt, a pair of socks, and a pair of panties from the victim. She noticed that there was a sanitary napkin or panty liner inside of the white cotton panties. Each item was placed in a separate paper bag and sealed. Nurse Wessell identified the paper sacks containing the T-shirt, socks, and panties taken from the victim on July 16, 1989. The sealed paper sacks containing the clothing evidence were turned over to Officer Wilson with the Litchfield police department. Nurse Wessell was present when the doctor examined the victim and took the vaginal and rectal samples and smears. She identified the sexual-assault evidence kit containing the blood samples and the rectal, vaginal, and oral smears and swabs and the head-hair and pubic-hair standards and combings taken from the victim on July 16,1989.

Nurse Wessell admitted on cross-examination that none of the victim’s clothing was torn or in disarray when she appeared at the emergency room. She also admitted that during the examination of the victim she did not notice any indication of apparent trauma to any area of the victim’s body.

Ross Wilson testified that he is a police officer with the City of Litchfield and that he was on duty during the early morning hours of July 16, 1989. He was called by St. Francis Hospital at 3:47 a.m. on that date to investigate a possible sexual assault. He left the hospital for a period of time to investigate the residence where the offense supposedly occurred but returned to the hospital at approximately 7 a.m. Officer Wilson took possession of three sealed paper bags and a rape kit from Nurse Vonna Wessell and identified these items in court. Officer Wilson turned the three bags and rape kit over to Chief William Dolahite at approximately 8 a.m. At no time did Officer Wilson open the three bags or the rape kit.

William Dolahite testified that he is chief of police for the City of Litchfield. Chief Dolahite testified that he received possession of a sealed cardboard box and three paper sacks from Officer Ron Wilson at his home on July 16, 1989, and he identified those items in court. Chief Dolahite took them to the police department around 9 a.m. and locked them in the refrigerator in the evidence room. On July 20, 1989, Chief Dolahite delivered these items, unopened, to William Frank in Springfield, Illinois, on July 20, 1989. Chief Dolahite also took possession of a sealed white envelope on August 24, 1989, from Sheriff Jim Vazzi, and he immediately took the envelope to William Frank at the lab in Springfield. The envelope was prepared by a lab technician at the Hillsboro Hospital. He identified the envelope as People’s group exhibit 17.

Jim Vazzi testified that he is the Montgomery County sheriff. He received possession of a large white envelope from Jim Schnarre, a lab technician at the Hillsboro Hospital, at approximately 10:30 a.m. on August 24, 1989, and identified the envelope as People’s group exhibit 17. Sheriff Vazzi delivered the envelope to Chief Dolahite approximately 15 minutes later. The envelope indicates that it contains specimens of pubic hair and head hair and three blood tubes taken from defendant.

James Schnarre testified that he is a registered medical technologist and is the director of the Hillsboro Hospital laboratory. He took blood, saliva, pubic-hair and head-hair samples from defendant at approximately 10 a.m. on August 24, 1989, at the hospital. Mr. Schnarre identified People’s group exhibit 17 and identified the samples contained therein. Mr. Schnarre also identified defendant in court as the person from whom he took these samples. Mr. Schnarre testified that he removed another set of samples from the defendant on a later date and identified People’s group exhibit 18 as the envelope containing specimens collected from defendant on September 15, 1989. He turned this envelope over to a police officer approximately 15 minutes later.

William Frank testified that he is a forensic scientist and that he is presently the DNA research coordinator with the Illinois State Police, Bureau of Forensic Sciences, at the Springfield Forensic Science Laboratory. As a forensic serologist Mr. Frank , receives and analyzes evidence, prepares a report of his findings regarding such evidence, and testifies regarding his findings in court. He completed a 21/2-year training program with the Illinois State Police in the analysis of blood, bloodstains, and body-fluid stains and analysis of hairs and fibers. He has also received forensic serology, training, other than from the Illinois State Police, in Minnesota, California, South Carolina, Florida, and Indiana and at the Federal Bureau of Investigation (FBI) Academy in Quantico, Virginia. He has testified on 20 occasions in the State of Illinois as a forensic serology expert, has conducted training courses in this area of expertise, and has published journals or articles in this specific area. Counsel for defendant conducted no cross-examination on the foundation of Mr. Frank as an expert in the science of serology, and the court so recognized William Frank as an expert in this field.

Mr. Frank testified that the typical examination is performed for the identification of either bloodstains or body-fluid stains on items of physical evidence. Body-fluid stains can include saliva, semen, or vaginal secretions. Mr. Frank explained that semen is composed of a liquid portion and a cellular portion and that the liquid portion contains organic components and certain proteins. Seminal stains can be identified by the presence in the evidence of one of the proteins present in the liquid fraction of the seminal fluid or the identification of spermatozoa present in the stain. Mr. Frank stated that if a semen stain is stored in a moist or humid environment bacteria can grow which will break down the spermatozoa but leave the protein in the stain intact. In that event semen can be identified, even in the absence of observing any spermatozoa, by the presence of the proteins. Mr. Frank noted that spermatozoa can last much longer in a cool dry environment. Mr. Frank also testified that from looking at the number of spermatazoa in a vaginal swabbing he can determine when that particular sample was taken from a victim.

Mr. Frank testified that blood is also composed of a liquid portion, called plasma, and a cellular portion. He can identify a bloodstain by reacting a sample with chemicals and antiserum. Blood is typed by identifying the ABO-blood-group substance on the cells in the blood and by identifying the antibodies that are present in the liquid portion of the blood. The ABO-blood-group system is an example of a genetic marker, a substance that is present in everyone but in different forms.

Mr. Frank also testified that 75% of the population are “secretor s,” or someone who secretes the ABO-blood-group type in his body-fluid secretions. If a male individual is a secretor, it is possible to detect that man’s blood factor in seminal stains he produced. This can be accomplished using a sample of seminal stain as small as a quarter of an inch in size. It is also possible to distinguish between stains. which are a mixture of secretions from two or more people.

Another example of a genetic marker is phosphoglucomutase, or PGM, which is an enzyme present in blood, semen, vaginal secretions, or other body fluids. Like the ABO blood type, PGM is found in everyone, but in different forms. The PGM test is run by a method called electrophoresis, where charged particles of PGM are moved through a gelatin-like substance to create a banding pattern from which you can determine the person’s PGM type.

Mr. Frank stated that the sexual-assault procedure which he follows is to generally examine the items of evidence for the presence of semen. He will search for possible semen stains and preliminarily perform a reaction test on the stain to see if it could contain semen. If that test is positive, he will look for the presence of spermatozoa or the presence of the seminal specific proteins.

Mr. Frank was involved in the investigation of the alleged sexual assault on the victim in the instant case. He identified People’s group exhibit 13 as one of the brown paper bags he received from William Dolahite of the Litchfield police. Mr. Frank testified that the T-shirt which was located in the brown paper bag tested negative for the presence of seminal material. He also collected hair and fibrous debris from the shirt which he placed in a plastic packet. The shirt and the plastic packet containing debris were resealed in the brown bag with evidence tape. Mr. Frank also identified People’s group exhibit 14 as another paper sack received from Chief Dolahite in this case; this sack contained a pair of socks. He similarly found no seminal material on the socks but collected debris therefrom, which was resealed with the socks in the bag.

Mr. Frank identified People’s group exhibit 15A-1 as another paper sack received from Chief Dolahite; this sack contained the victim’s underwear. Preliminary testing of the panties and panty liner showed the presence of seminal material by the identification of spermatozoa. Mr. Frank made marks on this item of evidence to show five questioned stained areas and unstained areas. He then cut portions of the stained areas on the panty liner and the panties and placed them in small plastic vials. He also placed unstained-portion samples into separate paper packets, and both the plastic vials and paper packets were then placed in liquid-nitrogen storage in order to preserve the genetic markers present on the evidence at that point in time. Mr. Frank stated that all evidence had been locked in his own individual laboratory storage vault to which no one else had access. Mr. Frank later tested the samples for the presence of the ABO and PGM genetic markers.

Mr. Frank also received a sexual-assault evidence-collection kit from Chief Dolahite on July 20, 1989. He performed genetic-marking tests on the blood located in the two tubes in the kit. He determined that the victim was type A of the ABO-blood-type system with type H activity, that she is an ABO group A secretor, and that she is a PGM type one minus. Mr. Frank also tested swabbings taken from the vietim’s mouth, vagina, and rectum for the presence of seminal material. He obtained a positive reaction for seminal material on the vaginal swabbing and a positive, but weaker, reaction on the rectal swabbing. The cotton material was cut off the swabs and placed into liquid-nitrogen storage.

Mr. Frank testified that he received a blood sample from the defendant for testing on August 24, 1989. He was able to determine that defendant was also a type A with H activity in the ABO-blood-type system and an ABO group A secretor. Defendant also has the same PGM type as the victim.

Mr. Frank tested the stains from the panty liner and panty crotch and vaginal swabs for presence of genetic markers. He found ABO group A with H activity present in the seminal-material stains but found inconclusive activity for the PGM genetic marker. Based on this testing, Mr. Frank opined that defendant’s seminal fluid could have made the stain on the undergarment and on the vaginal swab. The seminal-material stain could not have come from the victim because she is a female. He also stated that the high number of intact spermatozoa present on the vaginal swab led him to conclude that it was a recent deposition of seminal material.

Mr. Frank conceded on cross-examination, however, that the sample tested on the vaginal swab could have been contaminated with body fluids from the victim. He also admitted that the PGM testing was inconclusive because in some of the samples there was no PGM present and in others there was no readable activity. He accounted for this result by stating that the sample could have been degraded; unlike the ABO blood group which lasts forever, PGM degrades much more rapidly. Mr. Frank also admitted that 30% of the population are ABO group A blood type, A secretors, and that he did not analyze the blood type for the victim’s husband.

Mr. Frank identified People’s group exhibit 16J as a cardboard microscope slide holder containing slides produced from stain extracts from the vaginal swabs. After examining the slides, Mr. Frank sealed the cardboard box and placed it in the rape evidence kit. Mr. Frank identified People’s group exhibit 18F as a wooden slide box containing slides on which the collected hair samples were mounted. All exhibits were in Frank’s sole possession at the Illinois State Police Laboratory and sealed after they were used. Mr. Frank admitted on cross-examination that none of the hairs collected off the T-shirt or retrieved from the panties or panty liner could have originated from the defendant, based on comparison with samples taken from defendant.

Mr. Frank testified that there is another way to scientifically narrow down the group of people who might have contributed the seminal material found on the victim’s panties and that was by forensic application of DNA-typing methodology. DNA stands for deoxyribonucleic acid and is the genetic material found in all cells of the body containing a nucleus. The Illinois State crime lab does not at this time perform DNA testing, but this testing is available at the FBI laboratory in Washington, D.C., and at two private laboratories, Cellmark Laboratories and Lifecodes Laboratories.

On September 18, 1989, Mr. Frank prepared standards of the blood types of the victim and of the defendant from the blood samples he received at the State laboratory. He did this by placing a few drops of the blood sample on some sterile cotton cloth to dry. The cotton cloth was then placed into a separate envelope, sealed, and placed in the sexual-assault evidence-collection kit which was picked up by Officer Richard Elledge of the Litchfield police department along with exhibits 13, 14, and 15A, the paper sacks containing evidence in this case. He instructed Officer Elledge to mail the dried blood standards from the victim and the defendant, the samples of questioned stained areas from the panties, and the vaginal swabs to the FBI laboratory in Washington, D.C.

Officer Elledge testified that during his investigation of the alleged sexual assault of the victim he picked up the paper bag marked People’s exhibit 15A-1 from the Springfield forensic lab on September 22, 1989. The bag which contained the victim’s panties was stapled shut and sealed with blue evidence tape. He placed the bag along with the rest of the evidence for the case in his personal locker to which only he and Chief Dolahite had access. The bag remained in his locker until March 19, 1990, when it was turned over to counsel for defendant. Officer Elledge admitted on cross-examination that the bag was not refrigerated in his locker, but he stated that the room was air-conditioned.

Defendant stipulated that People’s exhibit 15A-1 was transferred by defense counsel to Dr. Robin Cotton at Cellmark Diagnostics Laboratories on March 21, 1990, by way of Federal Express. Defendant further stipulated that on April 16, 1990, one red-topped tube of blood and one purple-topped tube of blood, drawn on that date from the victim, and one red-topped tube of blood and one purple-topped tube of blood, drawn from defendant, were transferred to defense counsel by lab technician Jim Schnarre. Finally, defendant stipulated that on May 8, 1990, a sealed cardboard box was received by Julie Ann Light of Cellmark Diagnostics Laboratories, the box contained the four above-described blood samples of victim and the defendant, and the samples were in the same tubes, seals unbroken, in which they had been placed at the time of their drawing by lab technician Schnarre.

Robin Cotton, Ph.D., testified that she is employed by Cellmark Diagnostics in Germantown, Maryland. Cellmark uses the technology of DNA typing to determine questions of paternity or identification. Dr. Cotton is the research and development manager for Cellmark, and her responsibilities include research, review, and approval of work relating to the DNA-typing process and serving as a witness in court. Dr. Cotton holds bachelor of science and master of science degrees in biology and a doctor of philosophy degree in molecular biology and biochemistry. Dr. Cotton has coauthored several articles, two involving paternity and two related specifically to using DNA for identification. She is a member of the American Society of Cell Biology, the American Society of Human Genetics, and the American Academy of Forensic Science. She has qualified to testify approximately 30 times in about 15 different States as an expert witness in the use of DNA in identification testing. Counsel for defendant conducted no cross-examination on the foundation of Dr. Cotton as an expert in the field of DNA in identification testing, and the court so recognized Dr. Cotton as an expert in this field.

Dr. Cotton testified that DNA is that component of cells which carries all the genetic information. This information is passed on from parent to child and determines what the individual will look like, how the individual will function as a biological organism, and how the individual will develop throughout his or her life. Everyone, other than identical twins, will have different DNA.

DNA is found in the nucleus of the cell and will be the same no matter where in the body the cell is located. In each cell there are 46 chromosomes. The chromosomes come in 23 pairs, 23 chromosomes coming from the mother and 23 chromosomes coming from the father. Each of the 23 pairs of chromosomes can be distinguished in shape from the others. Each chromosome is a single long piece of DNA. Each of the 46 pieces of DNA is double-stranded and is shaped like a spiral staircase. Along the double-stranded DNA pieces there are four components or bases, which are abbreviated A, T, C, and G. These four bases are the alphabet, which forms “words” that the biological machinery of the cell can interpret. The information provided by the bases tells the cell what to do and how to work. The double-stranded feature of DNA allows it to pair bases in a certain way: an A is always paired across from a T, and a C is always paired across from a G. Dr. Cotton explained that the strand of DNA is like a “zipper” in that it can be chemically “unzipped” and then put back together again. It is that ability to take DNA apart and put it back together which is one of the major components in DNA identification technology

Dr. Cotton described the process utilized at Cellmark for extracting DNA. She stated that the technicians will take a biological sample, blood, saliva, semen, bone, or muscle tissue, and rupture the cells, releasing the DNA into a small amount of solution. Through a series of steps, they remove the unwanted portions of the cell, leaving a small amount of purified DNA.

Dr. Cotton noted that for identification purposes they will look for pieces of DNA that vary from one person to the next. A restriction enzyme is a protein that is isolated from bacteria and is used in the DNA identification technology to cut out pieces of DNA that will be useful in the identification process. The restriction enzyme is added to DNA in a test tube to cut it into pieces. The pieces of DNA are then spread out and separated by size by a process known as electrophoresis, so that the information can be read. This process utilizes a tray containing a quarter-inch layer of agarose, a gelatin-like substance, with indentations across one end. The DNA samples are placed in the indentations, and an electric current is placed across the gel. Because the DNA pieces have a slight charge, they will move in the electric field and the agarose gel acts like a sieve so that small pieces of DNA will move rapidly through the gel and larger pieces will move more slowly.

A nylon membrane is then laid across the gel, and over that, a number of paper towels and a weight. The paper towels absorb the solution in the gel so that the DNA and the solution will move up through the gel toward the towels with the DNA binding to the nylon membrane. This process is known as a Southern blot.

The next step in the process involves taking radioactively treated DNA, called a DNA probe, and adding it to a solution into which the nylon membrane has been placed. The probe functions with the DNA on the membrane for a period of 16 to 18 hours, allowing the pieces of DNA to zip up with pieces that have the opposite series of A’s, T’s, C’s, and G’s in a very specific manner, so that now there is radioactivity bound to each of these positions. X-ray film is then laid over the piece of nylon for each of the samples, the film is exposed to the dark, and everywhere that the probe bound to the pieces of DNA with the complimentary sequence, the radioactive emissions will expose the X-ray film showing dark bands. This process is known as autoradiography, and the developed film is called an autorad. The position of these bands on the autorad reflects the distance traveled or size of that piece of DNA.

Dr. Cotton explained that Cellmark uses four DNA probes at one time to produce a pattern of bands. This pattern will be compared with the pattern produced by the other samples in order to determine whether the samples were produced by the same person. If the patterns are different, they had to have been produced by different people. If the patterns are the same, the likelihood of whether the samples came from different people can then be calculated or estimated. She noted that all labs do not use the same DNA probes, but as long as the probe recognizes differences in people, it is useful for identification. Dr. Cotton stated that the probes used by Cellmark in the DNA identification process are generally accepted in the scientific community.

The entire process used by Cellmark Laboratories is listed in a protocol book and is followed by the technicians in the laboratory. The procedures were developed by the Cellmark group in England. She stated that the components for extracting DNA, the use of the restriction enzyme, the use of a gel, and the Southern blot procedure were all used for research purposes since the mid-1970’s. The concept of DNA identification was developed in the early 1980’s when it was discovered that DNA fragments varied enormously in the population. In 1985 Alen Jeffries discovered a set of probes which varied so much that it was highly unlikely that you would find two people that shared the same pattern of fragments, and Jeffries published research in that year hypothesizing that genetic information could be used to answer questions of paternity and questions of identification. Dr. Cotton stated that DNA testing has been used forensically since 1985 and on a commercial basis since 1987.

Dr. Cotton testified that Cellmark was engaged by the defense counsel to test certain evidence which was gathered in the investigation of the alleged sexual assault upon the victim in the instant case. The evidence which she received was a pair of underwear to which a sanitary pad was attached. Dr. Cotton identified People’s group exhibit 15 as the Federal Express envelope containing the evidence sent to Cellmark by defense counsel and received by Dr. Cotton on March 21, 1990. Dr. Cotton identified People’s group exhibit 15A-1 as the evidence contained in the Federal Express envelope and stated that the bag containing the evidence was sealed when it was received at Cellmark. She noted the receipt of this evidence on an evidence-receipt sheet in their laboratory contemporaneously with the opening of the bag.

Dr. Cotton and Julie Light, another Cellmark employee, examined the evidence and cut a small section from the panties, marking in blue ink the section on the fabric where the cutting was taken. The cutting was cut up into smaller pieces and placed into a tube marked “sample number 01.” The underwear was resealed in the paper sack. Dr. Cotton personally performed the extraction of the DNA from the sample taken from the underwear. The process involved extracting DNA from any non-sperm cells and then extracting the DNA from the sperm cells. This process can be accomplished because the outer walls of sperm cells are harder to rupture then the outer walls of other cells. Dr. Cotton stated that the final results showed that there were two people’s DNA that came from that sample taken from the underwear.

The extracted DNA samples, contained in small test tubes, were turned over to Ms. Light on May 7, 1990. Ms. Light performed the extraction of DNA from the standards submitted for the victim and the defendant. Dr. Cotton reviewed and concurred in the results of those extractions. Ms. Light also placed the DNA samples in the agarose gel and performed the electrophoresis, the Southern blot procedure, the DNA probe, and the autoradiography.

Dr. Cotton noted that it is not always possible to extract DNA from every item of evidence sent to the laboratory and that the process will not work if there is insufficient DNA in the sample. In the instant case, the sample taken from the underwear located in People’s group exhibit 15A-1 contained a sufficient amount of DNA in order to base an opinion as to whose DNA was contained on that exhibit.

Dr. Cotton examined the autorad pattern for the DNA extracted from the sample compared with the pattern for the DNA extracted from the standards which had been submitted to Cellmark Laboratories for the victim and the defendant. Dr. Cotton stated that she found DNA which had been extracted from the underwear sample consistent with having come from the victim and DNA that matched the DNA from defendant. Dr. Cotton did not offer an opinion within a reasonable degree of scientific certainty as to whether or not there was a match between defendant’s standard and the sample.

Dr. Cotton admitted on cross-examination that the greater percentage of human DNA is similar to the DNA of another individual; it is only by comparing the differing DNA that the DNA identification process is accomplished. She also admitted that it is important for the accuracy of the results that the DNA sample be adequately stored, for under certain conditions the DNA could be destroyed, in which case no result could be obtained under the DNA identification process. Dr. Cotton explained that the sample from which the DNA is to be extracted is affected by conditions such as the environment and temperature. Optimum storage conditions for various samples will differ; tissue samples should be frozen, whereas stains should be kept cool and dry. Dr. Cotton admitted that she had no background information on how the panties contained in People’s group exhibit 15A-1 had been stored prior to her receipt of them at Cellmark Laboratories. She stated, however, that while the DNA extracted from that article had degraded somewhat, it had not degraded to such an extent that it could not produce a usable pattern.

She also admitted that while the rate of movement of DNA in the agarose gel can be affected by the amount of DNA put in the indentation for each sample, there should not be any detectable difference as long as the sample quantities do not greatly differ. She stated that in the instant case she ran a preliminary process known as a yield gel or mini-gel on a small amount of the sample taken from the underwear evidence in order to estimate the proper quantity of sample to be placed in the agarose gel for the electrophoresis. Dr. Cotton stated that, in her professional opinion, only rarely are samples affected by contamination, such as bacteria, but in those cases the evidence was not properly stored so that the bacteria was allowed to degrade the stain. In those cases it will be apparent in reading the autorad that the DNA had been degraded. She denied that bacterial DNA will affect the migration of the human DNA in the gel. She stated that the DNA sample extracted from the panty cutting could have contained some bacterial DNA and she would not have detected that in her test.

Dr. Cotton testified that Cellmark Laboratories has been using the same four DNA probes for forensic purposes since she came to the company in January 1988. Their laboratory adds all the probes to the solution containing the membrane at once, while other laboratories add their probes one at a time. Another difference in their procedure from the other labs is that, after the four probes are added all at once, the membrane is washed and each probe is then added one at a time. She denied that it would be possible for the probes to attach to bacterial DNA under their testing conditions. She had heard of this phenomenon occurring at other laboratories, but it has never happened at Cellmark Laboratories.

Dr. Cotton testified that she was familiar with proficiency tests that were administered at Cellmark by the California Association of Crime Laboratory Directors. In these tests, the agency submitted two sets of 50 samples to Cellmark from which the laboratory had to extract the DNA and then identify DNA matches. The agency then checked Cellmark’s results with the correct answers. In each set of 50 samples Cellmark had one incorrect match due to an error on the part of the person doing the test. Dr. Cotton stated that in many instances if the lab technician performs a procedure incorrectly, there will be no obtainable result in the testing. However, if the mistake is mixing two samples together, then an incorrect result can result. Dr. Cotton stated that because the problems in the proficiency tests were due to human error, Cellmark has taken steps to analyze where in the process the error took place to minimize the chances of that same type of error occurring in the future.

Dr. Cotton admitted that she was familiar with the case, State of Delaware v. Steven Pinnell, because she gave testimony in that case. She stated that her testimony addressed the results of the California proficiency test and also the specific work done in that particular case. Dr. Cotton also was familiar with a Maryland case involving a stillborn baby abandoned in an automobile, in which Cellmark was asked to determine whether the baby’s DNA matched the DNA of the woman who owned the vehicle. Cellmark determined that there was a match between half of the DNA’s banding pattern for the baby (the other half coming from the father for whom no standard was available) and the standard for the woman. Dr. Cotton had no knowledge that the report issued was in error; she insisted that, to her knowledge, no charges were filed in the case because the infant was determined to be stillborn. Dr. Cotton testified that she was familiar with an article written by Eric Lander commenting on this Maryland case. Defendant did not pursue this line of questioning.

Dr. Cotton testified that she is familiar with the term “false positive,” which refers to an incorrect match or determination. She stated that there is a two-step process involved in analyzing the data from a DNA test: first, determine whether or not the two patterns match and, if they do, calculate the frequency with which this pattern would occur in the population. This calculation uses a population data base, such as for Caucasians, and involves extraction of DNA for 200 unrelated Caucasian individuals, viewing the DNA bands produced with a given DNA probe and determining how frequently a band in a given position with a given DNA probe occurs. She stated that the majority of the Caucasian samples were taken from a blood bank in Delaware.

Julie Ann Light testified that she is a staff molecular biologist employed for the last three years by Cellmark Diagnostics Laboratories in Germantown, Maryland, as a forensic case worker. In this capacity she is responsible for the evidence submitted to the laboratory, extraction of DNA from that evidence, and the entire remainder of the procedure and interpretation. Prior to her employment with Cellmark she was employed by a biochemical laboratory using the processes of hybridization, autoradiography, gel electrophoresis, and Southern blotting, and during this prior employment Ms. Light had the opportunity to work with these processes approximately 100 to 150 times.

Ms. Light holds a bachelor of science degree in zoology and is presently pursuing a master’s degree in forensic science from Georgetown University in Washington, D.C. She has processed over 130 forensic cases during her three-year employment at Cellmark Laboratories, and an average case involves three different pieces of forensic evidence. She has also performed these procedures in connection with her forensic training at Cellmark and in connection with the paternity-testing department in which she was involved prior to her forensic training and testing. Ms. Light has qualified to testify as an expert in the field of molecular biology as applied to DNA identification in 14 criminal cases in six different States.

Ms. Light admitted that Cellmark is only her second employment since she received her bachelor’s degree in 1984 and that she has not yet authored any articles in the field of DNA, is not a member of any scientific communities, panels, or organizations, and has not received any researchships in the area of molecular biology. She admitted that her only training in forensic cases has been received through her employment at Cellmark and that two of her supervisors did not have Ph.D. degrees. The supervisors in the laboratory who review her casework, however, do have doctorate degrees.

Part of Ms. Light’s training at Cellmark involved validation samples given to her by her supervisor on which she performed the entire DNA procedure and then reported her results. The samples included swabs which contained DNA from two differing sources, but she admitted that because the samples were received in the laboratory there was no chance of bacterial contamination. Over defendant’s objection the court recognized Ms. Light as an expert in the limited field of molecular biology as it relates to DNA identification.

Ms. Light testified that she first came into contact with evidence relating to the instant case on March 21, 1990, when People’s group exhibit 15 was received at Cellmark Laboratories. The exhibit was assigned to a particular scientist, Dr. Robin Cotton, and Ms. Light was present when Dr. Cotton opened the envelope containing the evidence. Ms. Light identified People’s group exhibit 15A-1 as the brown paper bag containing the evidence, a pair of underwear with a sanitary napkin attached and some hairs. She stated that a Polaroid snapshot was taken of the underwear on that date, and she identified People’s exhibit 23 as that photograph.

Ms. Light watched Dr. Cotton as she performed the DNA extraction on the underwear sample. The section of underwear was first placed in a tube with salt solution and detergent and placed in a water bath overnight. Next, the material in the tube was drawn up into the top of the tube, and the tube was placed into a centrifuge to draw the remaining moisture from the material. The dry material was placed into a second tube into which additional salt solution and a stronger detergent were added. Ms. Light stated that a pellet had formed in the bottom of the first tube after the centrifuge action, with a clear liquid on top of the pellet. That clear liquid was removed and placed into a third tube. Phenol chloroform, which acts to release DNA from cells, was added to the clear liquid in the third tube. More salt solution and detergent were added to the first tube containing the pellet and the second tube containing the material, and the material in the tube was again spun dry with the centrifuge. DNA was then extracted from the sperm cells in the the first and second tubes.

When Dr. Cotton completed the process she delivered the three tubes containing DNA to Ms. Light. The third tube, marked “Extract 1, ” contained a DNA extract from vaginal-wall cells (the woman’s DNA), while the first and second tubes, “Extract 2” and “Extract 3,” contained DNA from the sperm cells. A mini-gel electrophoresis was then run to identify the quality and quantity of DNA in the three extracts.

Ms. Light began her work on the case on May 7, 1990. Cellmark requires that certain parts of the DNA identification procedure be witnessed by another scientist, and Ms. Light testified that her work was so witnessed by a second individual. She received blood-sample standards from the victim and the defendant on May 8, 1990, and she identified People’s group exhibit 24A as the sealed box containing the standards on that date. She filled out an inventory sheet for the two tubes of blood taken from defendant and the victim.

The first step performed by Ms. Light in the extraction of DNA from the blood standards was the process known as lysing, which releases the DNA from the white blood cells found in the blood. In this process she added salt solution and detergent to a small sample of the blood and then added phenol chloroform to isolate and purify the DNA. She stated that she was able to extract DNA from the blood standards and then proceeded to the restriction enzyme portion of the test, which cuts the DNA into fragments. She explained that the enzyme is very specific as to the location on the DNA where the DNA will be cut, much like a molecular “scissors” which might cut a section of the newspaper everytime it comes across a particular word.

Ms. Light next ran the process known as gel electrophoresis. The DNA restriction fragments created from each of the samples were placed in perforations or lanes in the gel: extract 1, which was taken from the female cells found on the underwear; extracts 2 and 3, which were DNA taken from sperm cells located on the underwear; extract 02, which was DNA taken from the victim’s blood; and extract 03, which was DNA taken from the defendant’s blood. Ms. Light also loaded lanes in the gel with three control DNA fragments: Lambda, 1 KB, and TDS (DNA extracted from the blood of one of the Cellmark employees).

Ms. Light explained that when electrical current is applied to the gel, the DNA molecules begin migrating through the gel matrix, which acts like a sieve, such that the very small fragments which have been created with the restriction enzyme move more quickly through the gel than the larger fragments. This process continues for 20 hours, or until the Lambda control band reaches 20 centimeters, at which time the electrophoresis process is halted and a Polaroid picture is taken showing the migration of two of the three controls.

The gel is then washed with three buffers. The buffers act to “unzip” the DNA fragments. The process known as the Southern blotting is then performed, where the DNA fragments are lifted from the gel and incorporated on a nylon membrane in the same pattern they held after the electrophoresis. The next steps in the DNA identification process, where the DNA probes are added to the nylon membrane and the autoradiograph is created, were not performed by Ms. Light but were performed by two individuals in the hybridization laboratory.

Ms. Light testified that Cellmark’s sister company in Great Britain supplies them with DNA probes, which are sections of DNA for which the base sequence is known, for example, a whole string of “A’s,” a whole string of “C's,” or “A’s-T’s,” “A’s-T’s.” These sequences are tagged with radioactivity.

In the hybridization laboratory, the nylon membrane is placed into a tupperware container containing some solution, and the radioactive DNA probes are then added to the membrane. The radioactive base sequences will recognize and attach to fragments with the complimentary structure, i.e., the string of “A’s” will attach to a fragment which is all “T’s.” Any fragments which have not joined with the probe will not bind to the membrane and will be washed off the next day.

The radioactive piece of nylon membrane is put next to a piece of X-ray film for a certain length of time and developed, resulting in a picture of the DNA banding patterns called an autoradiograph. A typical DNA banding pattern will have at most eight bands in one lane; however, some people may only produce six or seven bands.

Ms. Light stated that an autoradiograph was produced by the hybridization department utilizing the procedure outlined above, and she identified People’s exhibit No. 26 as the original autoradiograph produced in this case. She stated that the first two lanes show the patterns for the control DNA (Lambda and 1KB); lane 3 was left blank; lane 4 shows the pattern for TDS, the internal control; lane 5 was a space; lane 6 shows the pattern for the female portion of the DNA extracted from the underwear; lane 7 was a space; lane 8 shows the pattern for the DNA extracted from the victim’s blood; lane 9 was a space; lane 10 shows the pattern for the 1KB control DNA; lane 11 is a space; lane 12 shows the pattern for DNA extracted from the defendant’s blood; lane 13 is a space; lane 14 shows the pattern for the DNA extracted from the sperm pellet in tube 1; lane 15 is a space; lane 16 shows the pattern for DNA extracted from the sperm fragment after the second washing of the material in tube 2; lane 17 is a space; lane 18 shows the pattern for the Lambda control DNA; lane 19 shows the pattern for 1KB control DNA; and lane 20 was left blank.

Ms. Light stated that she examined the autoradiograph to see if there were any banding patterns which matched one another. She explained that two banding patterns are said to be consistent if they visually appear to be closely aligned; however, for there to be an actual match between two bands, according to criteria determined by Cellmark Diagnostics, a computer camera enhancer must show alignment of the bands falling into one millimeter of space, plus or minus. She stated that this criterion was chosen because one millimeter is the measurement of the gel’s ability to differentiate one band from another within a gel. Ms. Light found that the banding pattern in lane 6, for the female DNA from the underwear, was consistent with the banding pattern for the victim’s DNA located in lane 8, but that these bands did not meet their match criteria. Ms. Light also found that the banding pattern from lane 16, containing DNA extracted from sperm obtained from the second washing of the material, matched the DNA banding pattern of the defendant’s blood, located in lane 12, and that the banding pattern from lane 14, which contained DNA extracted from the sperm pellet, was consistent with the banding pattern of the DNA extracted from defendant’s blood, located in lane 12. She explained the failure of the banding patterns in lanes 6 and 8 to meet the match criteria as possible degradation of the DNA from the vaginal portion of the underwear stain and opined that the failure of the banding patterns in lanes 14 and 12 to meet the match criteria was due to loading too much DNA in lane 14, more than there was in the comparable lane for the DNA from the defendant’s blood.

Ms. Light testified that in addition to her work being reviewed at various points in the process, her interpretation of People’s exhibit 26 was confirmed by at least two other scientists at Cellmark as part of its operating procedure. The purpose of this review and confirmation is to ensure that the procedure is followed adequately and to ensure that the scientist’s interpretation is correct.

Ms. Light was asked if she had reached a conclusion within a reasonable degree of scientific certainty as to the identity of the persons who contributed the DNA in the stains analyzed from the underwear submitted to Cellmark for DNA identification testing. Counsel for defendant objected to this question on grounds of foundation and also stated that Ms. Light was not qualified as an expert in this particular area to give a scientific opinion. The court overruled defendant’s objection, stating that Ms. Light’s qualifications and the extent of her experience went to the weight to be given to her opinion and not to its admissibility. The court further noted that it had already found Ms. Light to be qualified as an expert for purposes of this limited field. Ms. Light offered her opinion that the DNA banding pattern obtained from the underwear as it applied to the sperm section matches the DNA banding pattern obtained from the blood of the defendant. She also stated that visual and computer matching of the DNA bands is a scientifically accepted procedure for matching these bands. She noted that it was counsel for the defendant who submitted the underwear and the blood samples to the lab for this DNA analysis.

Ms. Light stated on cross-examination that the DNA probes only recognize human DNA and, so, if there were bacterial contamination of the sample, the DNA probes would not attach to the bacterial DNA. However, such contamination may also degrade the sample taken from the evidence, and if that occurred, portions of the band may disappear or there may be a slight variation in pattern. She also admitted that the rate of migration through the gel can be affected by contamination.

Ms. Light also - testified on cross-examination that there were some statistical analyses done as a result of the interpretation of this_ case, which she was involved in computing. She had concluded from this computation that the frequency in the Caucasian population, of which defendant is a member, of the DNA banding patterns attained from DNA extracted from sperm on the victim’s underwear and from the blood of the defendant was approximately 1 in 12,000. Ms. Light testified that statistical extrapolation is part of the standard procedure in the DNA analysis after a match is determined to be found. After counsel for defendant was informed of the results of the sample testing showing that a match existed and that further testing could be started, counsel informed Cellmark that further testing must be upon the advice of the State’s Attorney. The statistical computation was made at the request of the State’s Attorney’s office.

Dr. Michael Conneally testified for the State that he is a Professor of Medical Genetics and Neurology at Indiana University Medical Center in Indianapolis. Dr. Conneally holds a bachelor’s degree in science and master’s and doctorate degrees in genetics and statistics. Dr. Conneally is also nationally board certified in medical genetics since 1982. He is a member of the American Society of Human Genetics and is on the board of directors of this organization. He is also a member of the Human Gene Organization and the American Association for the Advancement of Science and is chairman of the genetics task force and on the scientific advisory council for the Muscular Dystrophy Association. Dr. Conneally teaches Ph.D. candidates and medical students and does research in the area of human genetics. His research work is focused on the human diseases known as muscular dystrophy, familial Alzheimer’s disease, and Hunington’s Chorea.

Dr. Conneally is the editor of the following journals: Human Heredity, the Journal of Medical Genetics, and the Journal of Neurogenetics, and his curriculum vitae, which lists the publications which he authored or to which he contributed, was admitted into evidence as People’s exhibit 29 for the purpose of establishing the doctor’s credentials. Dr. Conneally has testified as an expert over 100 times, mainly in the area of human genetics as it relates to paternity testing, but has testified on 12 occasions in eight States and twice in Federal court regarding forensic identification of DNA. Dr. Conneally admitted that he has never performed any DNA extractions, but he stated that he is in charge of the laboratory at Indiana University where such work is performed by technicians. He has examined at least 500 autoradiographs, however, in connection with his scientific research and in forensic cases. The court recognized Dr. Conneally as an expert witness in the field of human genetics and statistics, without objection by the defendant.

Dr. Conneally stated that it is generally accepted within the scientific community that a scientist may view an autoradiograph and determine whether it is of high quality or not. It is also generally accepted in the scientific community that a scientist such as himself may inspect an autoradiograph to determine whether there are any matching banding patterns.

Dr. Conneally is familiar with Cellmark Laboratories and the procedure used at Cellmark to extract DNA and produce autoradiographs from these extractions, from reading their protocol. He opined, over the objection of defendant, that the procedure used at Cellmark is generally accepted in the scientific community as being the proper procedure for the extraction and identification of DNA.

Dr. Conneally noted that there are only three laboratories in the United States which actually perform the DNA extraction and identification to be used in forensic cases: Cellmark, the FBI, and Life-codes. Dr. Conneally is also familiar with the procedure used by the FBI laboratory in Washington, D.C., for the extraction and identification of DNA in forensic cases and stated that their procedure is generally accepted in the scientific community as being proper. He similarly is familiar with the DNA extraction and identification procedure at Lifecodes Laboratory and at the FBI by reading publications reviewing their procedures. Dr. Conneally stated that the three laboratories use differing probes in their DNA identification processes for proprietary reasons, and he noted that if identification is done by more than one laboratory on the same sample using differing probes, the finding of matching bands by both laboratories becomes even more conclusive. Moreover, the fact that the laboratories use different restriction enzymes in their identification process does not impair the validity of the results.

Dr. Conneally testified on cross-examination that it is a generally accepted principle that every human being has different DNA, except for identical twins. He stated that there are perhaps 3 billion bases making up every human being’s DNA, 10% of which are functioning genes creating the proteins that make us what we are, and 90% of which are nonfunctioning DNA, unique to each individual. This 90% of human DNA includes so-called “VNTR’s” (variable number tandem repeats), pieces of DNA that repeat over and over in varying number from person to person, and accordingly VNTR’s are used for DNA identification purposes because they show the uniqueness of an individual. Dr. Conneally also explained that restriction enzymes are used in the DNA identification process to break off VNTR’s, and the radioactive probes are used to “light up” the VNTR’s that show the differences between people; those VNTR’s correlate to the bands seen on the autoradiograph. Dr. Conneally agreed that it was possible, if using one probe and viewing one band, to find a match coming from different people. However, Dr. Conneally opined, as more bands and more probes are used, the chances of getting a match from different individuals approaches zero.

Dr. Conneally is familiar with the case work done by Cellmark laboratories in the instant case, has reviewed the laboratory’s case file and autoradiograph produced as part of the DNA-identification procedure, and identified People’s exhibit 26 as that autoradiograph. He stated that he was able to determine by looking at this exhibit that the quality of production of this forensic autoradiograph is excellent and that Cellmark had been able to obtain sufficient forensic material to get good pattern results. Dr. Conneally admitted on cross-examination that he had not personally vie