If anybody could turn the history of genetic anthropology into a page-turner, it would be Bryan Sykes. Sykes, Professor of Human Genetics at the University of Oxford, has spent the better of part the last 25 years decoding the mystery of our species’ genetic ancestry through mitochondrial DNA analysis. He recounts his work in his 2001 book, The Seven Daughters of Eve: The Science that Reveals our Genetic Ancestry.
But Sykes doesn’t simply relate the major discoveries in the field. He goes one step further by breathing life into each of the seven major mitochondrial DNA clusters that are common today in European populations.
The Seven Daughters of Eve can be divided into two major parts. In the first, Sykes discusses some of his most fascinating work. He relives how he and his colleagues extracted ancient DNA from the 5,000-year-old Ã–tzi the Iceman, examines his work on understanding the origins of the Polynesians, and tells how he and his team discovered the true fate of Tsar Nicholas II and the Romanovs. With each story, Sykes easily manages to explain the scientific details behind his conclusions in a way that nearly any reader can comprehend.
23andMe customers will be most interested in Sykes’ explanation of how mitochondrial DNA can be used to trace individuals’ maternal ancestry. Mitochondrial DNA (mtDNA) is a small segment of circular DNA that is found in tiny organelles called mitochondria. It is believed that hundreds of millions of years ago, mitochondria were free-living bacteria who invaded more advanced cells and never left. Now, they are an integral part to every cell. For people like Bryan Sykes, however – not to mention 23andMe customers who are interested in their ancestry – mitochondria are mostly important for what their DNA can tell us.
Because of the way fertilization takes place, mitochondria (and thus mtDNA) are only passed from mother to child, like a kind of “matrilineal surname.” In the same way that surnames can change gradually over generations, so too does mtDNA. So while two siblings are almost certain to have identical mtDNA, people whose most recent common maternal ancestor lived thousands of years in the past are likely to bear substantially different mtDNA signatures.
As it turns out, the different mtDNA patterns found in populations around the world can be organized together into a global family tree. At the tips of the tree are present-day human populations from around the world. At the root of the tree is the common mtDNA ancestor of every human alive today, a real woman who lived in Africa about 175,000 years ago.
As with any family tree, some people are more closely related than others. Scientists have given these more closely related clusters, or ‘haplogroups,’ specifically designated letters. There are seven such haplogroups (and thus, seven letters) among people of European descent – U, K, H, V, X, T, and J.
These seven haplogroups form the basis for the second part of Sykes’ book. As a way of making them seem more personal to the reader, he gives them each a name. For example, haplogroup U becomes Ursula, X become Xenia, H becomes Helena, and so on. These are the so-called “Seven Daughters of Eve.”
Sykes uses these names to create stories based on where in Europe the descendants of each “daughter” are concentrated. In a chapter on haplogroup K (Katrine), he relates the domestication of wolves. The chapter on haplogroup J (Jasmine) is dedicated to the beginnings of agriculture in the Near East more than 10,000 years ago.
Sykes concludes his journey into our species’ genetic past by explaining why he feels it important to understand genetics from a personal standpoint. He writes, “I like this kind of genetics because it puts the emphasis back where it belongs: on individuals and their actions.” There are so many stories hidden in our genes, he reasons, and it is best to tell them to the public in this fashion.
This book is not without flaws. The anecdotes about Sykes’ research in the field are, by definition, centered on how he was the major player in each discovery. As a result, many important players in the field are marginalized or left out completely. In addition, the dramatic benefit of assigning each haplogroup its own story comes at the expense of accuracy and completeness. For example, haplogroup J (Jasmine) is not the only one associated with the origin and spread of agriculture form the Near East to Europe; but in The Seven Daughters of Eve, it is the only one mentioned.
However, simplifying and romanticizing genetic anthropology does make for a good story — which was Sykes’ goal in the first place. Indeed, Sykes has discovered many amazing stories in his years of research at Oxford, and The Seven Daughters of Eve proves to be an engaging journey that can be enjoyed by general audiences and genetic ancestry enthusiasts.
The Seven Daughters of Eve: The Science that Reveals our Genetic Ancestry
New York: W.W. Norton & Co.
Photo by SCM Studios/istockphoto