Short answers, pulled from the story.
The Ancient North Eurasian genetic component is defined by the Mal'ta boy skeleton labeled MA-1, which was discovered during excavations in the 1920s near the Mal'ta site in central Siberia. This individual lived approximately 24,000 years ago and represents one of the earliest known populations carrying this specific lineage.
Scientists model that the Ancient North Eurasian gene pool formed roughly 38,000 years before present when an early West Eurasian population mixed with an Ancient East Eurasian group. The resulting ancestry consists of approximately 65% West Eurasian components and 35% East Eurasian components.
Between 20,000 and 25,000 years ago a branch of Ancient North Eurasian people mixed with Ancient East Asians to lead to the emergence of Ancestral Native American populations. Estimates show that between 14% and 38% of Native American ancestry may originate from gene flow from the Mal'ta-Buret' population.
A genomic study published in 2021 identified early Bronze Age Tarim mummies dating from 2,135 to 1,623 BCE as primary descendants of a population represented by the Afontova Gora 3 specimen. These individuals show high genetic affinity with AG3 which accounts for about 72% of their ancestry.
The earliest known individual with the specific mutated allele rs12821256 of the KITLG gene is a female south-central Siberian ANE individual from the Afontova Gora 3 site who lived around 10,000 BP. Geneticist David Reich stated that the KITLG gene for blond hair probably entered continental Europe via a population migration wave from the Eurasian steppe.