HOW DO WE DEFINE A PERSON?

 I consider myself a person because I am self-aware.  There are probably not more than a dozen people in the US and perhaps a hundred in Sweden with my name, Elof Axel Carlson.  I can be identified by my anatomy which includes photographs of me at different stages of my life cycle. My 83 year old portrait is not too different from my 55 year old portrait but it is considerably different from my 30 year old unwrinkled appearance. My fingerprints, of course, have not changed since I was a youth. A very complete autopsy at my death would reveal a considerable amount of information about my various organs and tissues. I am also a person defined by the artifacts of my life.  I have a personality that is known to my family, students, and colleagues over the years. Readers know me through my books, articles, and this Blog.  For some of you it is as if I am conversing with you. I could add those items to a variety of social and historical facts to make a CV or curriculum vitae, which I used to use when I was seeking a job. It was used by deans and committees to create an overall impression of who I was as a person.  For the most part my written record would not give many clues to others about how I look or what my personality is like.

At a genetic level, I have a unique genome that no other person alive or dead has.  Our genomes can give some information about us as persons.  If there is an abnormal chromosome number, we could predict that a person with trisomy-21 has Down syndrome, trisomy-13 has Patau syndrome, trisomy-18 has Edwards syndrome, and for the sex chromosomes, individuals who are XXY have Klinefelter syndrome and those who have an unaccompanied X are said to have Turner syndrome.  Today people can have their genomes sequenced, partially or completely, depending on how much they are willing to pay. They can learn about their risks for a variety of disorders and get some insights into their ethnic or racial ancestry.  Their DNA might also reveal a number of physical traits.  But reading my entire genome will not tell you what books I wrote, what field I worked in, or the type of information you could obtain by reading my CV. At a physiological level, you could learn about my blood types, my HLA tissue antigens, and a variety of health conditions and past illnesses I have had. When my physicians do laboratory tests, they are interested in my risk factors for diabetes, heart attacks, strokes, and other diseases. If I were consumed by a fire and my jawbones were left relatively undamaged, my current dentist would be able to identify me from my extractions, implants, crowns, and fillings.

I have no conscious awareness of who I was before I was about three years old. I would be unaware of my name as a fetus, unaware of existing as a fertilized egg.  I think of personhood as a process of becoming rather than an event that is assigned by society as fertilization in an oviduct, implantation into a womb, birth that is recorded on a birth certificate, or concluded with a death certificate. Like Walt Whitman, I contain multitudes of people through their contributions to civilization – thousands of words coined over centuries, hundreds of ideas and values that I was taught and absorbed into my personality, and,  of course, some 25,000 genes that were transmitted from Swedish farmers, pious Lutherans, polytheistic Vikings, Orthodox Jews in Ukraine, survivors of pogroms, who some 1900 years ago were scattered by a Roman conquest of Jerusalem. 

Life Lines 100 -- PCR and Crime

About twenty years ago Kary Mullis discovered a technique to clone small amounts of DNA. He called this process polymerase chain reaction or PCR. DNA is our genetic material and indeed the hereditary stuff of all cellular life. The technique uses heat to separate the two strands of DNA and some fancy regions are attached, which allows primers that recognize them to begin copying the separated strands. The process takes a few hours to generate a million-fold increase in DNA of any given type.

The PCR technique is very useful for geneticists who wanted to study the isolated genes or fragments bearing genes from any organism. They can use the technique to study the DNA of long dead organisms from humans ancestors to extinct quaggas and dodos. But most striking has been the application of PCR studies to crime.

DNA is found in cells. We are composed of tens of trillions of cells. Every time we lick a stamp or envelope we leave some cells with our saliva on the paper and glue. When we drink from a glass, toss a tissue that we used to wipe our nose or mouth, we discard some of our cells. Dandruff flakes, hair, the aerosol of our sneeze can also scatter our DNA about. The man who rapes his victim leaves tell tale evidence on clothing. A criminal’s DNA will be found under the nails of a victim who scratches her assailant. Any cut by a criminal will leave drops of blood as evidence.

The first few years that PCR evidence was used to convict criminals, it was vigorously challenged by defense attorneys, just as early attempts to use fingerprints were resisted until the public and the courts got used to the accuracy of the methods used to establish identity. To the surprise, and disappointment, of district attorneys, the PCR evidence works both ways. Many convicted rapists were released because the crime, and not the criminal was convicted. Shady looking people at the wrong place and time are sometimes railroaded into prison and PCR has been their deliverance. Both the prosecution and the defense benefit from this reversal of fortunes because if the technique is valid the DNA evidence can be very convincing.

Why then did the jury reject the PCR evidence in the Simpson case? Some believe in conspiratorial theories – that Simpson was framed and his blood dribbled here and there by racist enemies. Some still discount the evidence because it is relatively new compared to fingerprints. There is another reason too. Juries consider what is right and wrong differently from professionals who know, teach, and practice the law. I remember, years ago, when Charlie Chaplin was very unpopular for his communist sympathies. He had an alleged affair of many months duration with a “crumpet girl,” whom he had befriended. She became pregnant. She sued for child support. A test for blood groups (the method then in use in some 40 years ago) revealed Chaplin was not the father. He was convicted. Why would a jury convict a person whose sperm did not produce this child? I remember reading a comment of one of the jurors: Chaplin cohabited with her; he could have been the father; he can afford it; it was only luck that someone else was also intimate. Sometimes a moral view prevails over a technical one.