Thursday, October 4, 2012

Whole-Genome Sequencing of African Hunter-Gatherers Reveals Human Genetic Diversity

According to a recent article on, a new study by a University of Pennsylvania researcher has found that whole-genome sequencing of African hunter-gatherers give insights into how humans have adapted to distinct local environments over evolutionary history. Published in the scientific journal, Cell, on July 26, 2012, the study has significantly furthered knowledge about the scope of genetic diversity in humans.

Because all modern humans originated from the African continent, it contains the highest level of genetic diversity in the world. Study author Sarah Tishkoff noted that although African populations have been instrumental in today's understanding of human evolutionary history, very little is known about variation in African genomes. Until now, scientists have only analyzed six African genomes, sequencing regions several times to reach the highest possible accuracy.

To better grasp the foundations of human genetic diversity and natural selection in diverse environments, the team sequenced the entire genome of 15 African hunter-gatherers from 3 different population: forest-dwelling, short-statured Pygmies from Cameroon, and click-speaking Hadza and Sandawe individuals from Tanzania. Researchers were able to identify over 13 million variations in DNA sequences in those genomes; more than 3 million of which were absent from existing databases.

This study also revealed signs of natural selection in genetics: compared to other populations, the hunter-gatherer populations showed distinct DNA patterns in genes involved in immunity, metabolism, smell, and taste, leading researchers to the conclusion that human populations adapted to specific environments.


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