Genetic archaeology finds parts of our genome more closely related to orangutans than chimps
January 26, 2011
In a study published online today in Genome Research, in coordination with the publication of the orangutan genome sequence, scientists have presented the surprising finding that although orangutans and humans are more distantly related, some regions of our genomes are more alike than those of our closest living relative, the chimpanzee.”
The fossil record helped to establish evolutionary relationships and estimate divergence times of the primate branch leading to humans, but not until the advent of genome sequencing technology has it been possible to learn more detail about speciation times, genetic and phenotypic divergence times, and the genetic variation present in common ancestor species.
With the addition of the orangutan to the collection of sequenced primate genomes, an international group of scientists led by Mikkel Schierup and Thomas Mailund of Aarhus University in Denmark set out to shed light on these questions in primate evolution. “There remains signals of the distant past in DNA,” said Mailund, “and our approach is to use such signals to study the genetics of our ancestors.”
When a population “splits”, the genetic variation they each inherit from the common ancestor will change over time as the populations diverge, possibly giving rise to two different species. Because humans, chimps, and orangutans all have a common ancestor, it is possible that humans and orangutans may still share genetic variants that were later lost in more closely related primates.