Origins of Paleoindians - Paleoindian Genes

Paleoindian Genes

Further information: Genetic history of indigenous peoples of the Americas

The gene pool of Paleoindians (and today's Native Americans) may have also received contributions from ancestors of the present-day Ainu. The Ainu are an ancient culture of hunters, gatherers, and farmers who still live on the Japanese island of Hokkaidō and the Kurile Islands in the archipelago north of Japan. A small population of Ainu still survive. They possess features of both Japanese and the European Caucasoid: light complexions, wavy hair, and sturdy bodies .

In addition to the Ainu, other present-day hunter-gatherer societies that have remained isolated in northeast Asia and North America and whose ancestors may have contributed to the gene pool of Paleoindian are the Yukaghir, Inuit, Aleut, Koniag, Kamchadal, Chukchi, and Koryak. However, in one anthropological study, only three groups of Gm allotypes (i.e. special blood proteins) were found in Native Americans. One group is supposedly that of the Paleoindians (which also includes thousands of Central and South American Indians) and the second is that of the Inuit and Aleuts. Another study involving mitochondrial DNA suggests a single founding tribe diverged into 4 specific mtDNA lineages responsible for 95% of all Amerindian genotypes. These 4 lineages may have roots in present-day Siberian, Mongolian, and Tibetan populations. A fifth lineage known as Haplogroup X (mtDNA) has been associated with European or Eurasian populations .

The most telling physical evidence for the ancestry of the first Americans is a unique "shovelling" of the two central upper incisors. The posterior surface of the teeth is hollowed like a shovel and referred to as sinodonty. Sinodonty is common amongst populations of Native Americans in North, Central, and South America; and in Turkestan (from the Caspian Sea to the Gobi Desert), Southeast Asia, the Pacific Islands, and Siberia. A population of Sami from Finland are also classified as sinodonts.

Opposed to sinodonty, sundadonty is found from Africa to Central Asia and Scandinavia. Most, but not all prehistoric North and South American human remains display a common Asian ancestry, including the skulls found in Minnesota which are dated to about 8,500 years. The well-known Kennewick Man remains are thought to exhibit sundadonty. .