Obviously, Aboriginal blood runs in the veins of Quebecers, believe many of them. How could the first French immigrants who arrived in Quebec without women have resisted the charm of the Aboriginals? However, genealogical and genomic studies of the contemporary Quebec population reveal that barely 1% of its genome comes from Aboriginal people.
“Quebecers overestimate their Aboriginal origin. Genomic studies have shown them wrong,” warns Simon Gravel, associate professor in the Department of Human Genetics at McGill University.
Researchers from the CHU Sainte-Justine Research Center and UQAC have applied themselves to estimating the importance of the contribution of Aboriginal peoples to the genetics of the current Quebec population. Their results were published last month in the scientific journal PLoS One. To achieve this, they analyzed the genome of 205 Quebecers established in different regions of Quebec whose genealogy they reconstructed using the BALSAC population file, as well as that of 52 North American Aboriginals. They also had genomic data from Europeans, including the French.
The genealogical analysis indicated that among the 8424 founders (that is to say the most distant ancestors that can be found in the parish and civil registers of Quebec), 39 were of Aboriginal origin. “This value of 39 is surely underestimated because there are probably some that have not been documented, or it is possible that individuals mixed together before the start of registrations in the civil registers”, underlines Claudia Moreau, first author of the article, in an interview.
Based on genealogical data, the researchers therefore estimated that the average Aboriginal contribution represents 0.35% of the genome of today’s Quebecers.
In addition, the researchers used three different methods to analyze the genome of the participants. These methods gave very similar results, indicating that on average, about 1% of the genome of Quebecers comes from Aboriginal people. “There are very few individuals who share much [de matériel génétique] with Aboriginal people, while many of them share little or none at all, which partly explains the average of 1%,” says Ms.me Moreau.
“You also see that the Aboriginals didn’t contribute a lot, in the sense that they may have had fewer children — and therefore fewer descendants — than other founders who contributed a lot to the contemporary population,” she adds.
One percent contribution is very little, but it is also explained by the fact that the interbreeding between Aboriginal peoples and European settlers mainly took place at the beginning of the colony, at the turn of the 17th century.e century. The good ten generations between the time of these crosses and the current population greatly contributed to diluting the genetic contribution of the Aboriginal people, notes Ms.me Moreau, who is currently a research professional at the Genopop laboratory at UQAC.
“A person born from the union between an Aboriginal parent and a European parent will have approximately half of his genome which will be Aboriginal, and the other which will be European. And if this person mates with a European, his descendant will only have a quarter of his genome which will be autochthonous. However, subsequent unions were generally between Europeans. So, if the crossing took place several generations ago, it is normal that today it is very diluted, because the European genome has taken over,” she explains.
The genetic data of the Quebecers sampled precisely made it possible to specify that the majority of interbreeding between Aboriginals and Europeans took place approximately 435 years ago, which means that 14 generations separate these Aboriginal ancestors from current Quebecers.
“The contribution of the Amerindians occurred especially at the beginning of colonization because then, the Amerindians were victims of ostracization, of acculturation, advances Claudia Moreau. We imagine that at the beginning of colonization, the Amerindians were very helpful for the first immigrants who did not know how to survive. There was probably more interaction then, but then, once the colony got bigger, they were needed less and then people mixed less. »
The genomic analysis methods used also made it possible to distinguish, in the genome of Quebecers, the Aboriginal and European contributions, but also a probably Siberian contribution from Europeans before the colonization of America.
Very short segments of DNA with indigenous characteristics have in fact been identified as coming from very old crosses, which occurred around 1890 years ago, probably between Europeans and Siberians, who, it should be remembered, also came to colonize the American continent, where they became the Native Americans of America, explains the researcher.
To explain the discrepancy between the estimate of 1% of Aboriginal contribution obtained by genomic analyzes and that of 0.35% resulting from the genealogical study, the researchers put forward the hypothesis that “the genealogical information about the Amerindian origin of the ancestors is probably incomplete because it had not been recorded by the priest in charge of the parish registers or because it was unknown for various reasons, such as an adoption or an illegitimate birth”.
“Our sample of 205 Quebecers is relatively small. Maybe, by chance, we recruited people who didn’t mix well. But we still have a good correlation: we see that individuals who share a greater part of their genome with Aboriginal people also have a greater Amerindian contribution to their genealogy. It’s reassuring. We are therefore quite confident that our results are reliable,” says Ms.me Moreau.
One thing is certain, Native Americans certainly added genetic diversity to that of the first Europeans who came to colonize these overseas lands, affirm the authors of the article.