Spencer Wells reveals the depth of human ancestry
Spencer Wells, a leading population geneticist, National Geographic Explorer-in-Residence, and Frank H.T. Rhodes professor at Cornell University, revealed his thoughts on the depth of human ancestry at a recent keynote lecture at the Virginia Bioinformatics Institute’s Conference Center.
The lecture, which took place on Oct. 7, was part of the 10-year anniversary celebration of the Virginia Bioinformatics Institute at Virginia Tech.
Wells received his doctorate in biology from Harvard University in 1994 and went on to pursue a postdoctoral fellowship at Stanford University's School of Medicine. An interest in the study of genetic diversity in populations blossomed into a personal quest to learn more about early human migration.
In 1996, Wells began his field studies in human population genetics with a survey of Central Asia. This work helped to advance the understanding of the Y chromosome, the male sex-determining chromosome found in most mammals, and its role in tracing ancestral human migration. Today, Wells devotes much of his time to communication of his scientific discoveries through books and film.
In his lecture, Wells explained the origins of the Genographic Project, which has led him and his team to over 36 countries across the globe. The project analyzes DNA from people around the world to learn more about the history of human migration. “The questions we are interested in are related to origin and journey,” said Wells. “Are we all related? If so, how closely? How did we come to occupy every corner of the globe?”
According to Wells, the question of origin is a question of genealogy or how the line of descent of humans today can be traced from a common ancestor. “Our understandings of genetics and developments in molecular biology have given us access to a molecular clock that allows us to look at human evolution in a way that complements the approach of paleontologists and others. It allows us to count backwards in time and build a wider picture of our human ancestry.”
By looking at mitochondrial DNA and the genetic makeup of the Y chromosome, the work suggests that all humans alive today are likely descended from one man, Y-chromosomal Adam, who lived in Africa 60,000 to 90,000 years ago. The Genographic Project is also revealing how populations have migrated within and out of Africa to colonize the planet in a very short space of time. “Through the Genographic Project, we have collected 65,000 samples from indigenous and traditional groups across the globe. Analysis is underway of the data and the first scientific publications have already appeared or will be published shortly,” said Wells.
The public can also play a part by ordering non-medical testing kits and helping to trace their own ancestral migrations. Money raised from the sale of these test kits is used to support not-for-profit projects around the globe that help to give back to indigenous communities.
“What is becoming clear from our studies is the indelible imprint that climate change can have on the migration of populations,” concluded Wells. “Climate change appears to have been a big driving factor for the exodus of populations from Africa to the rest of the world via the Saharan gateway, events that are deep in our human ancestry. In a very short period of time, occurrences like Hurricane Katrina can have a huge impact on the migration of populations. Much remains to be discovered but we are catching a fascinating glimpse of our deep ancestry and learning more about what it means to be human.”