Pollen grains analysis helps understand how the first humans migrated from Africa across Europe and Asia.
The pollen data showed that warming temperatures supported forests that expanded into Siberia and facilitated early human migration there.
They compared Pleistocene vegetation communities around Lake Baikal in Siberia, Russia, to the oldest archaeological traces of Homo sapiens in the region.
Pleistocene period is considered two million to 11 thousand years ago and as the time of human evolution.
The study focuses on a migration event that occurred approximately 45,000-50,000 years ago.