Genetic history of the Indigenous peoples of the Americas

The genetic history of the Indigenous peoples of the Americas is divided into two distinct periods: the initial peopling of the Americas from about 20,000 to 14,000 years ago, and European contact about 500 years ago. The first period of the genetic history of Indigenous Americans helped shape the genetic makeup we see today.

Indigenous American populations share ancestry with an Ancient East Asian lineage, which split from other East Asians before the Last Glacial Maximum. They also have genetic connections to Ancient North Eurasians, a group from Siberia. These groups later spread throughout the Americas starting about 16,000 years ago, with some groups like the Na-Dene and Eskimo–Aleut arriving later.

Studies of genetics show that early groups may have stayed isolated in Beringia before moving into the New World. Some Indigenous American groups in South America have been isolated since the first people arrived there. The Na-Dene, Inuit, and Native Alaskan populations have unique genetic markers, showing they came from later groups that settled the northern parts of North America and Greenland. Scientists have found similar patterns when studying Indigenous American language groups and blood types.

Autosomal DNA

Main article: Autosome

See also: Human genetic variation

Indigenous American populations come from a group of people who lived in East Asia. They share ancestry with people from this area, but they split off from them before many other groups did.

Studies show that the first people to live in the Americas came from Asia, moving across the Bering Strait. Over time, these groups spread out and became the many different Indigenous populations we see today. Most of these groups share a common ancestor from East Asia, but there were a few different waves of people moving into the Americas.

One important discovery came from studying the DNA of a very old baby found in Montana. This baby's DNA matched closely with DNA from Indigenous Americans today, showing that they all come from a common group that lived near Siberia.

More recent studies have confirmed that all Indigenous Americans come from one main group that split from East Asians and mixed with other ancient groups. These studies also show that the people who first moved into the Americas divided into different groups fairly quickly after they arrived.

Y-chromosome DNA

Main articles: Y chromosome and Human Y-chromosome DNA haplogroup

The Y-chromosome DNA helps us understand the ancestry of Indigenous American men. A "Central Siberian" origin has been suggested for the fathers of the first people who moved into the Americas.

Membership in haplogroups Q and C3b shows that a person has Indigenous American paternal ancestry.

The micro-satellite diversity and spread of a Y lineage found only in South America suggest that some Indigenous American groups became separated after the first people settled in their areas. The Na-Dene, Inuit, and Native Alaskan groups show haplogroup Q (Y-DNA) changes, but they are different from other Indigenous Americans with various mtDNA and autosomal DNA (atDNA) changes. This suggests that the earliest people who moved to the far north of North America and Greenland came from later groups of migrants.

Haplogroup Q

Main article: Haplogroup Q-M242

Q-M242 is the special mark that defines Haplogroup Q (Y-DNA). In Eurasia, haplogroup Q is found among ancient Afontova Gora remains and Indigenous Siberian populations, like the modern Chukchi and Koryak peoples, as well as some Southeast Asians, such as the Dayak people. Two groups have many people with the Q-M242 change: the Ket (93.8%) and the Selkup (66.4%) peoples. The Ket are thought to be the only remaining people from ancient wanderers living in Siberia. There are fewer than 1,500 Ket in Russia.²⁰⁰² The Selkup have a bit more people, with about 4,250.

During the Paleo-Indigenous American period, a small group of people carried the Q-M242 change and moved to the Americas across the Bering Strait (Beringia). One person in this group had a new change, creating the Q-M3 change. These people with Q-M3 moved all over the Americas.

Haplogroup Q-M3 is known by the rs3894 (M3) change. The Q-M3 change is about 15,000 years old, matching when the first Paleo-Indigenous Americans moved into the Americas. Q-M3 is the most common change in the Americas, at 83% in South American groups, 50% in Na-Dene groups, and about 46% in North American Eskimo-Aleut groups. With very little Q-M3 moving back to Eurasia, the change likely happened in east-Beringia, or more exactly the Seward Peninsula or western Alaskan interior. The Beringia land started to sink, cutting off land paths.

Since finding Q-M3, several smaller groups of M3-carrying people have been found. For example, in South America, some groups have a lot of the M19 change, which defines the subclade Q-M19. M19 has been seen in 59% of Amazonian Ticuna men and 10% of Wayuu men. Subclade M19 seems special to South American Indigenous peoples, starting 5,000 to 10,000 years ago. This suggests that groups became separated and maybe even formed tribes soon after moving into South America. Other American subclades include Q-L54, Q-Z780, Q-SA01, and Q-M346 lines. In Canada, two other lines have been found. These are Q-P89.1 and Q-NWT01.

Haplogroup R1b1a1a2 (M269)

Main article: Haplogroup R1b1a1a2

R1b1a1a2 (M269) is the second most common Y-DNA haplogroup in Indigenous Americans after Y-DNA haplogroup Q.

The R1b1a1a2 (M269) lines usually found in Native Americans are part of the R1b1a1a2 (M269) subclade most common in western Europeans, and its highest amount is in many Algonquin-speaking tribes in eastern North America.

So, many writers think R1b most likely came through mixing during European settlement after 1492.

R1b1a1a2 (M269) is mainly in North American groups like the Ojibwe (50-79%), Seminole (50%), Sioux (50%), Cherokee (47%), Dogrib (40%) and Tohono O'odham (Papago) (38%). It is most common in northeastern North America and gets less common from east to west. In southwestern Native American tribes, this haplogroup is only about 4%.

Haplogroup C-P39

Main article: Haplogroup C-M217

Haplogroup C-M217 is mainly in Indigenous Siberians, Mongolians, and Kazakhs. Haplogroup C-M217 is the widest and most common branch of the bigger (Y-DNA) haplogroup C-M130. Haplogroup C-M217's descendant C-P39 is most common today in Na-Dene speakers, with the highest amount in the Athabaskans at 42%, and smaller amounts in some other Indigenous American groups. This special and separated branch C-P39 includes almost all Haplogroup C-M217 Y-chromosomes in all Indigenous peoples of the Americas.

Some researchers think this might show that the Na-Dene people moved from the Russian Far East after the first Paleo-Indigenous American settlement, but before modern Inuit, Inupiat and Yupik expansions.

Besides Na-Dene peoples, haplogroup C-P39 (C2b1a1a) is also in other Indigenous Americans such as Algonquian- and Siouan-speaking groups. C-M217 is found in the Wayuu people of Colombia and Venezuela.

Data

Listed here are notable Indigenous peoples of the Americas by human Y-chromosome DNA haplogroups based on related studies. The samples are from people known by the ethnic and linguistic names in the first two columns, the fourth column (n) is the number of people studied, and the other columns show the amount of each haplogroup.

Mitochondrial DNA

Main articles: Mitochondrial DNA, Human mitochondrial genetics, and Human mitochondrial DNA haplogroup

Many Indigenous American families share special genetic groups found in their mitochondria, which are small parts inside cells that give energy. These groups are called haplogroups, and four main ones—A, B, C, and D—are common among Indigenous Americans and some people from far-east Asia.

One special group, called X, is also found in Indigenous Americans. Most of these families belong to a smaller part of X called X2a, which is mostly found in North America. Scientists think these genetic groups came from a small group of women who lived in Asia long ago. These women’s families moved into the Americas thousands of years ago, probably through a land path called Beringia, which connected Asia and North America back then.

When scientists study these special genetic groups, they find that they all come from a few families who lived in East Asia. These families moved into the Americas, probably through the Bering Strait area, and then spread quickly across the whole continent. Some older genetic groups have disappeared since then, possibly because of big changes that happened later in history.

Genetic admixture

Main article: Genetic admixture

Ancient Beringians

Main article: Ancient Beringian

Recent discoveries in Alaska have shown the existence of a special group called "Ancient Beringians." These people were one of the first groups to live in the Americas. Scientists found DNA from an old Indigenous girl in Alaska that did not match the two main groups of Indigenous Americans we know about today. This DNA showed that there might have been just one big group of people who first came to the Americas, and later split into different groups. This group of people lived about 20,000 years ago and are ancestors of many Indigenous American groups today.

Old world

See also: Multiracial Americans

When Europeans came to the Americas, many new mixes of people happened. In places like South and Central America, Indigenous people, Europeans, and Africans who were brought over as slaves mixed together. This created many new groups of people.

In North America, European traders married Indigenous women, and their children became known as Métis. In the United States, many people say they are Indigenous American, but some cannot prove their family ties to Indigenous groups. This has caused some problems for Indigenous communities.

European diseases and genetic modification

Scientists studied the DNA of ancient and modern Indigenous Americans and found changes in genes that help fight diseases. These changes happened after diseases like smallpox came to the Americas with Europeans. This made it harder for Indigenous people to fight new diseases.

Blood groups

Main article: ABO blood group system

Before scientists learned about DNA, they studied human genetics using blood proteins. The ABO blood group system was discovered by an Austrian scientist named Karl Landsteiner in 1900. Blood types are passed from parents to children and are controlled by a single gene with three versions: i, I^A, and I^B.

Research during World War I showed that blood group frequencies differ around the world. Blood type O is very common globally, occurring in 63% of all people. It is especially common among Indigenous peoples of the Americas, particularly in Central and South America, where almost everyone has type O. In Indigenous North American populations, type A ranges from 16% to 82%. This suggests that the first Indigenous Americans came from a small, isolated group.

One explanation for the high number of type O individuals is genetic drift. Because the original population was small, blood type diversity may have decreased over time. Another idea is that many people with types A and B died from diseases brought by Europeans, leaving mostly those with type O.

The Di^a antigen of the Diego antigen system is found only in Indigenous peoples of the Americas and East Asians, and in people with ancestry from these groups. The frequency of this antigen varies widely among Indigenous American groups, from almost 50% to 0%, and is linked to language families and environmental conditions.