When Christopher Columbus came to the New World, your teacher says in hushed and disapproving tones, he encountered the equal people there and called them “Indians” because he thought he had reached India. She rolls her eyes to show you how Columbus was stupid, and he was stupid because he was evil, not realizing that these people were equal to him in every way.
In reality, Columbus called the inhabitants of these places “Indians” because he correctly noted two aspects of their physiognomy: they were at least predominantly Asian in descent, and they were brown and not “yellow,” which by the calculus of human races meant that they were ethnically something like Indians.
As it turns out, they were a different type of Asian entirely and lacked the paternal European line that runs through India, but they were Asian immigrants just the same, only ones who had arrived over ten thousand years earlier via a Bering land-bridge along with other groups who subsequently were absorbed or exterminated.
In fact, Asian immigration to the new world took place in several waves, with caste variations intact. The leaders of the Inca, Aztec and Maya did not resemble the 90% of their population who were essentially serfs, but were taller, thinner and more intelligent. In the same way, whoever built the ancient civilization of Cahokia was likely more intelligent than their servants, but the servants lived on after that civilization collapsed, just like how Mexico today is mostly populated by the descendants of the serfs of the Maya, whose civilization was in decline before Europeans arrived, and Aztec, whose empire had surrounded itself with enemies who welcomed the Spanish conquest as a chance for revenge. Although the groups which arrived from Siberia were mixed in caste, they shared a similar origin and spread out across the Americas, differentiating themselves in the process.
These data suggest that Native American male lineages were derived from two major Siberian migrations. The first migration originated in southern Middle Siberia with the founding haplotype M45a (10-11-11-10). In Beringia, this gave rise to the predominant Native American lineage, M3 (10-11-11-10), which crossed into the New World. A later migration came from the Lower Amur/Sea of Okhkotsk region, bringing haplogroup RPS4Y-T and subhaplogroup M45b, with its associated M173 variant. This migration event contributed to the modern genetic pool of the Na-Dene and Amerinds of North and Central America.
All sources agree that the majority of Amerind genetics comes from a group that was at least living in Siberia, Mongolia or Manchuria which then moved into Siberia and across the Bering Strait, which at that time was either a land bridge or small continent called “Beringia.” This group may have acted like a genetic snowball, picking up other groups along the way, suggesting that the Amerind migration consisted of multiple groups crossing the Bering Strait:
They concluded that all Native Americans, ancient and modern, stem from a single source population in Siberia that split from other Asians around 23,000 years ago and moved into the now-drowned land of Beringia. After up to 8000 years in Beringia—a slightly shorter stop than some researchers have suggested (Science, 28 February 2014, p. 961)—they spread in a single wave into the Americas and then split into northern and southern branches about 13,000 years ago.
…But the Science team also found a surprising dash of Australo-Melanesian DNA in some living Native Americans, including those of the Aleutian Islands and the Surui people of Amazonian Brazil. Some anthropologists had previously suggested an Australo-Melanesian link. They noted that certain populations of extinct Native Americans had long, narrow skulls, resembling those of some Australo-Melanesians, and distinct from the round, broad skulls of most Native Americans.
They picked up some additional groups along the way, although these were a minority of the genetic material:
Nearly one-third of Native American genes come from west Eurasian people linked to the Middle East and Europe, rather than entirely from East Asians as previously thought, according to a newly sequenced genome.
…DNA from the remains revealed genes found today in western Eurasians in the Middle East and Europe, as well as other aspects unique to Native Americans, but no evidence of any relation to modern East Asians.
…While the land bridge still formed the gateway to America, the study now portrays Native Americans as a group derived from the meeting of two different populations, one ancestral to East Asians and the other related to western Eurasians.
This makes for a changing summary of the genetic data which stays true to its roots — a Bering Strait migration by Asiatic people — but adds depth as a good history would have:
On the other hand, genetic data have demonstrated a close resemblance between the aboriginal Siberian tribes living east of the Yenisey River and northern Mongoloid populations, and similarities among populations dwelling to the west of the Yenisey River and European populations.
…Although there is general agreement among scholars that the first human inhabitants of the Americas came from Asia, the exact geographic source, number of migrations, and timing of these population movements remain controversial. The evidence in support of an Asian origin of New World populations is based on anatomical resemblance in contemporary populations, craniometric affinities, cultural similarities, and genetic similarities.
…In contrast, studies of maternally-inherited mtDNA have presented a variety of competing scenarios ranging from one to six separate waves of Asian migrants starting as long ago as 30,000 BP. Furthermore, there are different proposals for which “source” populations in Asia gave rise to New World populations: Viral distribution data implicate Mongolia/Manchuria and/or extreme southeastern Siberia as the ancestral homeland of the Amerinds; whereas, mtDNA data point to Mongolia, North China, Tibet, and/or Korea as the candidate source regions in Asia.
This includes the possibility of multiple migrations from multiple sources, potentially by boat as well as by land, over the course of ten thousand years:
There is also a controversial variant of the coastal migration model, put forward by archaeologists Dennis Stanford at the Smithsonian Institution in Washington DC and Bruce Bradley at the University of Exeter, UK. Called the Solutrean hypothesis, it suggests that coastal migration from Asia could have been supplemented by parallel migrations across the Atlantic, bringing stone-tool technologies from present-day Spain and southern Europe to eastern North America.
The Asiatic appearance with some additional details suggests ancient admixture into the mostly-Siberian group:
Before 24,000 years ago, the ancestors of Native Americans and the ancestors of today’s East Asians split into distinct groups. The Mal’ta child represents a population of Native American ancestors who moved into Siberia, probably from Europe or west Asia. Then, sometime after the Mal’ta boy died, this population mixed with East Asians. The new, admixed population eventually made its way to the Americas. Exactly when and where the admixture happened is not clear, Willerslev said. But the deep roots in Europe or west Asia could help explain features of some Paleoamerican skeletons and of Native American DNA today. “The west Eurasian [genetic] signatures that we very often find in today’s Native Americans don’t all come from postcolonial admixture,” Willerslev said in his talk. “Some of them are ancient.”
In other words, Amerinds are Siberian immigrants, and in addition to making local species extinct, they likely absorbed other tribes and created a new culture out of this racially-mixed group, which in part explains the relatively few successes of the New World, mainly because admixed populations lose the strengths of the original groups because traits are created by many genes, and not all of these are passed on, causing mixed-race people to have partial versions of the traits that were fully expressed in the unmixed group.