For ASPM, the variation arose about 5,800 years ago, roughly correlating with the development of written language, spread of agriculture and development of cities, he said.
"The genetic evolution of humans in the very recent past might in some ways be linked to the cultural evolution," he said.
The resulting tree matches many existing ideas about language development.
Spanish and Portuguese come out as sisters, for example - both are cousins to German, and Hindi is a more distant relation to all three.
All other Indo-European languages split off from Hittite, the oldest recorded member of the group, between 8,000 and 10,000 years ago, the pair calculates.
Around this time, farming techniques began to spread out of Anatolia - now Turkey - across Europe and Asia, archaeological evidence shows.
Francis Collins, director of the National Human Genome Research Institute.
"We, including scientists, have considered ourselves as sort of the pinnacle of evolution," noted lead researcher Bruce Lahn, a University of Chicago geneticist whose studies appear in Friday's edition of the journal Science.Cookies Zuid maakt gebruik van cookies om een optimale gebruikerservaring te kunnen bieden.Met cookies kunnen we de manier waarop de site gebruikt wordt vastleggen en analyseren.Cookies van derde partijen zorgen er ook voor dat we filmpjes kunnen toevoegen aan berichten en sharebuttons voor social media aan kunnen bieden. Onze service-afdeling is te bereiken op telefoonnummer 088-8002002. So suggests new research that tracked changes in two genes thought to help regulate brain growth, changes that appeared well after the rise of modern humans 200,000 years ago.
Rather than compare entire dictionaries, they used a list of 200 words that are found in all cultures, such as 'I', 'hunt' and 'sky'.