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Where did I come from? Well, Pittsburgh, sure, and I know the stork didn't bring me (well, Mom was never exactly clear on that point). But I mean, who am I, how did I get to be me, the me that I am? In many ways, that is what this website is about. I am striving for an understanding of myself by learning about my ancestors, the people who, in a very real sense, made me. Of course, I am also the product of my environment and of how I have interacted with that environment, as is also true for each of my ancestors. So, in addition to finding out who they are, I am also trying to find out about their lives and their times. This includes their relatives, which helps to explain why this website covers as many people as it does. I am not unusual in this: genealogy is the number one hobby in the United States. Yet, there is a limit to how much we can discover from documented sources about our ancestors, and the further back in time we attempt to go, the less we are likely to find. But, there is another way which allows us to go back before the invention of writing to find out more about ourselves. Each of us carries within the nucleus of every cell of our bodies (except for egg, sperm and red blood cells), two complete copies of the human genome--the complete set of human genes. One of these sets came from our father, the other came from our mother. The genome can be looked at as a book, in 23 chapters, that describes the recipe for how we are put together. Each chapter is a chromosome. The book is written from an alphabet of only four letters, put together in words containing only three, and always three, chemical 'letters'. These words are written on long strings of DNA molecules (see reference 1). Half of the genes in my 'book' came from my father and the other half came from my mother. The same is true of both of my parents, so one quarter of my genes came from each of my four grandparents, etc, all the way back to the dawn of time. How can we use this to discover more about ourselves? Mitochondria are structures that exist in every cell in the body outside of the cell nucleus. Their purpose is to help the cell use oxygen to produce energy. Each mitochondrion contains a piece of DNA. Unlike the DNA contained within the cell nucleus, mitochondrial DNA is inherited from only one parent, our mother (see reference 2). Scientists have been able to show that every person on earth is descended, in one sense, from one woman who lived about 100,000 years ago, whom they named Mitochondrial Eve. She was not the only woman alive at the time, but, since mitochondrial DNA comes only from our mother, any woman who only has sons will not pass on her mitochondrial DNA. It is not hard to see, with a little thought, that if x (x is any number you want it to be) women are alive at any given moment, if you look ahead far enough, all but one of their trees will have ended in all sons, leaving everyone alive at that point to be descended, in terms of mitochondrial DNA from only one of those women. Recently, research by Professor Brian Sykes of the Institute of Molecular Biology at Oxford University in England has shown that all persons of European descent are descended, in a mitochondrial sense, from one of only seven women, whom he has dubbed the Seven Daughters of Eve. For those not of European descent, he has identified 33 daughters worldwide. His book, The Seven Daughters of Eve, tells something of the lives of each of these women, when she lived, and what part of Europe her descendants are most likely to have settled in. He has founded a company, Oxford Ancestors, which has a website, http://www.oxfordancestors.com. They offer to determine for you which daughter you are descended from by analyzing a specimen of your DNA. My analysis indicates that I and my siblings (you guys know who you are), but not my daughters, are descended from Helena. My Maternal Line: HELENA->... -> ->Hannah Gibson Chappell->
Mitochondrial DNA tells you about your descent through the line of women that ends with your mother. For males, Y-chromosome analysis, also by Oxford Ancestors, says something about your paternal ancestors. I have also received the results of this analysis.
References Genome, the Autobiography of a Species in Twenty-three Chapters, Matt Ridley, HarperCollins Publishers, 1999 The Seven Daughters of Eve, Brian Sykes, Norton, 2001 |
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