By Sudarshana Banerjee
National Geographic and IBM’s Genographic Project scientific consortium have developed a new analytical method that traces the relationship between genetic sequences from patterns of recombination – the process by which molecules of DNA are broken up and recombine to form new pairs. By looking at similarities in patterns of DNA recombination that have been passed on and in disparate populations, Genographic scientists confirm that African populations are the most diverse on Earth, and that the diversity of lineages outside of Africa is a subset of that found on the continent.
By the way, that’s Chris Darwin – the great-great-grandson of Charles Darwin. He is not brushing his teeth (on the picture). Chris swabbed with the Genographic Project to test his and therefore his paternal great-great grandfather’s DNA. You can find the results here.
The divergence of a common genetic history between populations showed that Eurasian groups were more similar to populations from southern India, than they were to those in Africa. This supports a southern route of migration from Africa via the Bab-el-Mandeb Strait in Arabia before any movement heading north, and suggests a special role for south Asia in the “out of Africa” expansion of modern humans.
The new analytical method looks at recombinations of DNA chromosomes over time, which is one determinant of how new gene sequences are created in subsequent generations. Imagine a recombining chromosome as a deck of cards. When a pair of chromosomes is shuffled together, it creates combinations of DNA. This recombination process occurs through the generations.
Recombination contributes to genome diversity in 99 per cent of the human genome.
The recombination study highlights the initial six-year effort by the Genographic Project to create a comprehensive survey of human genetic variation using DNA contributed by indigenous peoples and members of the general public, in order to map how the Earth was populated. Nearly 500,000 individuals participated in the project. This database is one of the largest collections of human population genetic information ever assembled, says IBM.
The Genographic Project seeks to chart new knowledge about the migratory history of the human species and answer age-old questions surrounding the genetic diversity of humanity. The project is a nonprofit, multi-year, global research partnership of National Geographic and IBM with field support by the Waitt Family Foundation.
IBM Research is IBM’s information technology research organization, with about 3,000 scientists and engineers at nine labs across the world. The Computational Biology Center at IBM Research was formed in 1995, and conducts research related to IBM’s business in healthcare, life sciences and high-performance computing.
(Sudarshana Banerjee is consulting editor with techtaffy.com. She can be reached at [email protected])