The conclusion will be controversial, as there is no consensus on where Indo-European languages came from.
Some linguists believe that Kurgan horsemen carried them out of central Asia 6,000 years ago.
If those genes don't work, babies are born with severely small brains, called microcephaly.
Using DNA samples from ethnically diverse populations, they identified a collection of variations in each gene that occurred with unusually high frequency.
"The genetic evolution of humans in the very recent past might in some ways be linked to the cultural evolution," he said.