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Sarah Tishkoff

Penn Genetics and Biology professor Sarah Tishkoff co-led a study looking into Africa's early history by examining 180 genomes from a dozen ethnic groups, Nature reported. Nearly one-fifth of the genetic variation her group identified was previously undocumented.

Tishkoff's study has the potential to promote diversity in genome research, which has largely focused on people of European descent. The research could also reveal new information and challenge assumptions about early human history in Africa. Tishkoff and her colleagues presented the study at the American Society of Human Genetics meeting in San Diego, but the study is currently unpublished.

At the presentation, Tishkoff said the study was “the most comprehensive whole-genome sequencing from groups that represent the ancestral diversity of humans."

The researchers found that over 40,000 years ago, the San and the Baka Pygmy groups were approximately twice as large as other ethnic groups in Africa. They also found evidence that the Hadza and Sandawe, two major hunter-gatherer groups, may have shared a common ancestor. This could potentially cause a major shift in the understanding of migration patterns in early African history.

In a Forbes column, geneticist Jennifer Raff wrote that Tishkoff's work "will substantially change our understanding of human history within the continent."

Raff also stressed the importance of improving diversity in genome research. "While researchers have been making great strides in the use of genomics for both medical and historical questions, the vast majority of participants in such studies are of European descent," Raff wrote.

A 2009 Nature study found that 96 percent of participants in genome-wide association studies were of European descent, which has prevented members of marginalized communities from benefiting from scientific research — such as access to medicine or infrastructure development. 

Tishkoff has also previously conducted research in Africa; in Oct. 2017, her lab traveled to the continent to study different genes controlling for variations in skin color.

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