Wells did his Ph.D. work under Richard Lewontin, and later did postdoctoral research with Luigi Luca Cavalli-Sforza and Sir Walter Bodmer. His work, which has helped to establish the critical role played by Central Asia in the peopling of the world, has been published in journals such as Science, American Journal of Human Genetics, and the Proceedings of the National Academy of Sciences. Wells is renowned for his logistically complex sample-collecting expeditions in remote parts of the world. , which in 1998 took him and his team from London to the Altai Mountains on the Mongolian border, via an overland route through the Caucasus, Iran and the -stans of Central Asia, was sponsored by Land Rover. In 2005 he led a team of Genographic scientists on the first modern expedition to the Tibesti Mountains in northern Chad, and in 2006 he led a team to the Wakhan Corridor on the Tajik-Afghan border. His work has taken him to more than 100 countries. He wrote the book , which explains how genetic data has been used to trace human migrations over the past 50,000 years, when modern humans first migrated outside of Africa. According to Wells, one group took a southern route and populated southern India and southeast Asia, then Australia. The other group, accounting for 90% of the world's non-African population, took a northern route, eventually peopling most of Eurasia, North Africa and the Americas. Wells also wrote and presented the 2003 PBS/National Geographic of the same name. By analyzing DNA from people in all regions of the world, Wells has concluded that all humans alive today are descended from a single man who lived in Africa around 60,000 – 90,000 years ago, a man also known as Y-chromosomal Adam. From 2005-2015, Wells led The Genographic Project, undertaken by the National Geographic Society, IBM, and the Waitt Foundation, which aimed to create a picture of how our ancestors populated the planet by analyzing DNA samples from around the world. The project is credited with creating the personal genomics industry. He has presented the results of his work around the world, including at the 2007 TED conference, where he spoke specifically about human diversity. Wells was a keynote speaker at the Science & Technology Summit in The Hague on November 18, 2010. He also gave the keynote address at the University of TexasCollege of Natural Sciences commencement exercises on May 21, 2011. Wells was one of the keynote speakers at the Jamboree that was co-sponsored by the International Society of Genetic Genealogy on June 3, 2013. The focus was on Family History and DNA: Genetic Genealogy in 2013, where he was quoted as saying:
Since 2005, the Genographic Project has used the latest genetic technology to expand our knowledge of the human story, and its pioneering use of DNA testing to engage and involve the public in the research effort has helped to create a new breed of "citizen scientist." Geno 2.0 expands the scope for citizen science, harnessing the power of the crowd to discover new details of human population history.
Allegations of anti-Semitism
In July 2020, Wells attracted criticism for tweeting that Israel should be bombed “until the sand turns to glass” and “ou’re Apartheid oppressors. You deserve to die.” The The University of Texas at Austin subsequently distanced itself from Wells, stating, “Spencer Wells is no longer a faculty or advisory council member at UT. He previously had a courtesy, unpaid appointment as a part-time adjunct that did not involve teaching. That ended in May and was not renewed. We do not have any association with the views held by Mr. Wells.” National Geographic subsequently removed all of Wells' content from its site, citing a violation of its journalistic ethics policy.
