Some people eat, sleep and chew gum, I do genealogy and write...

Tuesday, June 11, 2019

The History of the Development of Genealogical DNA: Part Nine: Without Leaving a Fingerprint

The development of using fingerprints for criminal investigations set the stage for the use of DNA in the courtroom and most recently the use of DNA in genealogical research. The concept was that fingerprints were individually unique but that fact had to be established in court before fingerprints were generally accepted for identification purposes in or out of a criminal investigation. The use of fingerprints in criminal investigations had a rocky start and it was several years before fingerprint evidence was generally accepted by courts around the world. The first case in the United States is explained in an article posted on entitled, "The First Criminal Trial That Used Fingerprints as Evidence." There has been a trend in the courts moving fingerprint evidence from producing a prima facia case to being used more to corroborate other evidence.

The case of Colin Pitchfork the first person to be convicted in a criminal case by DNA evidence is summarized in Wikipedia: Colin Pitchfork.
Colin Pitchfork (born 23 March 1960) is a British convicted murderer and rapist. He was the first person convicted of murder based on DNA fingerprinting evidence, and the first to be caught as a result of mass DNA screening. Pitchfork raped and murdered two girls in Leicestershire, the first in Narborough, in November 1983, and the second in Enderby, in July 1986. He was arrested on 19 September 1987 and sentenced to life imprisonment on 22 January 1988, after admitting both murders.
To move from the scientific circles into the courtroom and then be accepted by the public were all necessary steps to DNA's acceptance as a tool for genealogical research. The techniques for using DNA in criminal cases became known as "DNA fingerprinting." The definition of DNA fingerprinting is as follows:
DNA fingerprinting is a method used to identify an individual from a sample of DNA by looking at unique patterns in their DNA.
A major step in understanding DNA was the Human Genome Project. Here is a description of the Project from Wikipedia: Human Genome Project
The Human Genome Project (HGP) was an international scientific research project with the goal of determining the sequence of nucleotide base pairs that make up human DNA, and of identifying and mapping all of the genes of the human genome from both a physical and a functional standpoint. It remains the world's largest collaborative biological project. After the idea was picked up in 1984 by the US government when the planning started, the project formally launched in 1990 and was declared complete on April 14, 2003. Funding came from the US government through the National Institutes of Health (NIH) as well as numerous other groups from around the world. A parallel project was conducted outside government by the Celera Corporation, or Celera Genomics, which was formally launched in 1998. Most of the government-sponsored sequencing was performed in twenty universities and research centers in the United States, the United Kingdom, Japan, France, Germany and China. 
The Human Genome Project originally aimed to map the nucleotides contained in a human haploid reference genome (more than three billion). The "genome" of any given individual is unique; mapping the "human genome" involved sequencing a small number of individuals and then assembling these together to get a complete sequence for each chromosome. Therefore, the finished human genome is a mosaic, not representing any one individual.
Genome variations are differences in the sequence of DNA from one person to another. Quoting from a Genome News Network ( article entitled, "Genome Variations:"
The more closely related two people are, the more similar their genomes. Scientists estimate that the genomes of non-related people—any two people plucked at random off the street—differ at about 1 in every 1,200 to 1,500 DNA bases, or "letters." Whether that's a little or a lot of variation depends on your perspective. There are more than three million differences between your genome and anyone else's. On the other hand, we are all 99.9 percent the same, DNA-wise. (By contrast, we are only about 99 percent the same as our closest relatives, chimpanzees.) 
Most genome variations are relatively small and simple, involving only a few bases—an A substituted for a T here, a G left out there, a short sequence such as CT added somewhere else, for example. Your genome probably doesn't contain long stretches of DNA that someone else's lacks. 
If the genome were a book, every person's book would contain the same paragraphs and chapters, arranged in the same order. Each book would tell more or less the same story. But my book might contain a typo on page 303 that yours lacks, and your book might use a British spelling on page 135—"colour"—where mine uses the American spelling—"color."
It is these minute differences that are the basis for using DNA to identify criminals, help in genealogical research and assist in the diagnosis of some inherited diseases. The differences between individuals come for mutations or mistakes that occur in the DNA sequence with cell division. Determining the relationship of two humans is accomplished by matching the patterns of DNA variations.

Once again, I need to return to the question of the degree of genetic detail genealogists need to know to use the results of a DNA test to determine family relationships? The use of familial DNA relationships in criminal investigations is very similar to using similar information to determine the degree of relationship between any two individuals. It is my opinion that all of the concerns raised in the use of DNA evidence in a criminal trial should become considerations for evaluation and use of genealogical DNA tests.

Essentially, when we are doing an analysis of DNA variations, we are looking for similarities and differences in patterns. Over the years, the examination process has become more accurate and detailed. At the same time, the genealogically oriented websites that have DNA testing have developed sophisticated DNA data matching programs that provide suggested matches as well as tools for determining relationships. I am sort of back to my original car analogy, how much do you need to know about electric motors and internal combustion engines to drive a car? The same question applies, in its own way, to the use of DNA tests for genealogical research.

Going back to the legal system, the use of DNA evidence in criminal trials has had a rocky history that parallels the use of fingerprints. The stages of acceptance have progressed from initial doubts about their usefulness to almost exclusive use for prosecution and then to backing off from reliance and putting the DNA or fingerprint evidence into the same category as any other evidence raised in the course of a criminal trial. These changes are reflected in the current instructions given to jurors who serve in a criminal court trial. The role of jury instructions in a criminal trial is not something that you can learn from the media representations of criminal investigations and trials. But in real life jury trials for major crimes, the drafting and selection of jury instructions are a major component of the entire criminal justice process. Additionally, an examination of the jury instructions is illustrative of the way DNA test results should be viewed by careful genealogical researchers. The American Bar Association has a lengthy document entitled, "Standards on DNA Evidence." The important steps include the acquisition of the sample with proper permission from the person providing the sample, preservation of the integrity of the sample, maintenance of the chain of custody, tested by an accredited testing laboratory, and interpreted by qualified personnel.

You should be able to see that very few of these steps are followed when collecting with a genealogically oriented kit. There are no procedures which guarantee that the DNA sample sent to the DNA company actually came from the person purchasing the kit and sending in the sample. Of course, the consequences of a mixup or bad sample are not serious except in the case of the use of the test results for a "familial" DNA connection in conjunction with a criminal investigation.

This all for now, but stay tuned for an expansion on the interrelationship of DNA testing in both the genealogical and criminal prosecution areas.

See these previous posts:

Part One:
Part Two:
Part Three:
Part Four:
Part Five:
Part Six:
Part Seven:
Part Eight:


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