We were able to reconstruct the genetic history of Gaspesian groups by combining knowledge of ascending genealogies with genetic data and historical facts. Neither genealogical nor genetic data alone would have allowed us to perform this historical reconstruction. The origin of the founders, especially those of non-European descent, is often missing and unreported, which leads to a patchy and incomplete picture of Amerindian contribution. On the genetic side, some lost lineages can be genetically retraced if their DNA was lucky enough to be preserved (Rasmussen et al., 2010). Others, such as the lost Amerindian lines of Gaspesian Acadians survived in other populations. However, in the absence of genealogical records that retrace their historical pathways, learning about their geographical distribution would require much more extensive genetic surveys of the whole population of Quebec. This emphasizes the complexity of human migration history and that of particular genetic lineages. It also emphasizes the pitfalls of inferring origins from uniparentally inherited markers (King et al., 2007).
Clearly, in addition to the female founders of New France who came from France, some of whom are known as the “Filles du Roi” (Charbonneau et al., 1987), the Native American “Filles de Godasiyo” (a legendary woman chief from the East) also made a significant genetic contribution to the Quebec population and can be traced in the genealogical record. Both arrived early and significantly contributed to the peopling of a new territory. Curiously, the carriers of Amerindian lines virtually disappeared from the population group that still identifies itself with its Acadian ancestors. Could we attribute this to allele surfing (Edmonds et al., 2004; Klopfstein et al., 2006; Excoffier et al., 2009), whereby a genetic variant gains in frequency in a population during its expansion into a new territory, while remaining modestly represented in its place of origin. Indeed, during the colonization of a new territory, pioneer families always have a chance to contribute more alleles to future generations than later migrants, which leads to founder effects (Labuda et al., 1996; Labuda et al., 1997). At the same time, a small number of pioneers in such an advancing population may often increase genetic drift, the chance of extinction and also the frequency of some initially rare alleles (Excoffier et al., 2009). The addition of other phenomena, such as a correlation in family size over generations, which amounts to inheritance of fertility, even if it can be also due to social selection, would further tend to reinforce the impact of a founder effect (Austerlitz & Heyer, 1998). This has been particularly well studied in Eastern Quebec in the region of the Charlevoix and Saguenay (Bouchard & DeBraekeleer, 1991; Scriver, 2001). An unprecedented abundance of maternal lines of Amerindian origin in Gaspesia, particularly among French-Canadians and Channel Islanders, provides insight into possible mechanisms that reinforce a surfing effect (Klopfstein et al., 2006). In addition to chance, there are other contributory factors: (i) Amerindian line carriers were among the first settlers (as in the forefront of a migration wave), (ii) a shortage of women among subsequent immigrants favoured the early mtDNA variants (Bedoya et al., 2006), and (iii) to reinforce it all, these particular settlers enjoyed great reproductive success (Fig. 2), a characteristic of the whole territory of New France (Austerlitz & Heyer, 1998; Livi-Bacci, 2001). On the other hand, neither chance nor embracing Gaspesian newcomers can explain the selective disappearance of Métis families from Carleton and Bonaventure (Fig. 3 and Fig. S2), which left behind the settlers who continued to preserve their Acadian identity. This requires a separate historico-sociological analysis.