Franco-Americans, Acadians, Cajuns and the Genetics of New France: 8,500 French Founders, Four Centuries On

From Quebec City in 1608 to the Cajun bayous of Louisiana in 1785, the French presence in North America rests on a small founding pulse: approximately 8,500 settlers who crossed the Atlantic from France to New France between 1608 and 1760, plus around 800 to 1,000 founders who built Acadia between 1604 and 1755. Today, more than 11 million people in Quebec, Acadia, New England, and Louisiana descend from this restricted founder pool. Their genetic profile, four centuries later, has remained strikingly French. On the Global25 PCA, six anonymized Quebec samples and five anonymized Cajun samples analyzed for this article cluster directly with French regional populations of Normandy, Poitou-Charentes, Picardy (Nord), and Île-de-France, with average distances of 0.0107 to 0.0118 to French_Nord, smaller than the distance between two French regions of mainland France. The historical sources, the BALSAC parish-record genealogy of four million entries, and the autosomal data all converge on the same picture: New France was settled overwhelmingly by people from western and northwestern France (Normandy, Aunis, Saintonge, Poitou, Île-de-France, Brittany), and the descendants of those founders remain genetically French today, with very small Indigenous American admixture (typically less than 2 percent at the population level, often 0 percent in individuals), almost no Iberian admixture outside specific Cajun families, and a founder effect that gave rise to remarkable subregional structure inside Quebec itself, most notably the Saguenay-Lac-Saint-Jean and Gaspé Acadian capsules.

1. The founding pulse: 8,500 French in Quebec, 1,000 in Acadia

The French presence in North America has three demographic anchors, each with its own founding history. The first is the St. Lawrence valley, settled by Samuel de Champlain at Quebec City in 1608 and by Paul Chomedey de Maisonneuve at Montreal in 1642. The second is Acadia, founded by Pierre Dugua de Mons and Champlain at Port-Royal in 1604, twenty-one years before any English settlement of comparable continuity. The third is the seasonal Atlantic fishing presence, established by Norman, Breton and Basque cod fishermen at the Newfoundland banks from the 16th century onward, formalized by the foundation of Plaisance in 1660 and surviving today as the French overseas collectivity of Saint-Pierre-et-Miquelon.

The first stream is by far the most demographically important. Approximately 8,500 settlers from France crossed the Atlantic between 1608 and 1760 and founded the demographic core of modern French Canada. These were not random emigrants. Their geographic origins concentrate heavily on the western and northwestern French coast, with the Paris basin contributing a substantial proportion via the Filles du Roi program. After the British Conquest of 1760, French immigration to North America stopped almost completely, and the French-speaking population of Canada expanded for the next two centuries almost entirely through natural increase, with one of the highest birth rates documented in any human population.

2. Where in France did they come from?

The geographic origin of the New France founders is one of the best-documented aspects of European migration to the Americas. The French Crown maintained meticulous emigration records, the Catholic Church recorded marriage and baptism contracts in both France and the colonies, and modern researchers (notably the BALSAC project at the Universite du Quebec a Chicoutimi) have reconstructed the parish-record genealogy of essentially the entire historic French Canadian population. The result is unambiguous: the founders of French Canada came from a remarkably restricted set of French provinces, with five regions providing the vast majority of the demographic input.

The geographic concentration is striking. If we add up Normandy, Poitou, Aunis-Saintonge, Île-de-France, and Brittany, we account for more than 70 percent of Quebec founders and more than 85 percent of Acadian founders. The two big colonial streams therefore drew from the same broad zone of western and northwestern France, with two important differences. First, the Quebec stream had a much stronger Île-de-France (Paris) component, mostly via the Filles du Roi program. Second, the Acadian stream had a much stronger Poitou (Loudunais) concentration, with families like the Melansons, Therriaults, Leblancs and Bourgeois tracing to a handful of villages around Loudun, Martaize, and La Chaussee.

The four French regions that supplied the bulk of New France founders: Lower Normandy (Calvados, Manche, Orne, with the Perche zone particularly important), Picardy and Nord-Pas-de-Calais (the northern French coast and inland), Île-de-France (the Paris region, source of about half of the Filles du Roi), and Poitou-Charentes (especially the Loudunais, source of about 50 percent of Acadian founders, and the Aunis with La Rochelle as the main port of embarkation). Brittany and Pays de la Loire (shaded lighter) contributed sailors, fishermen, and a portion of the later Acadian resettlement. The remaining regions of France contributed only marginal numbers of founders to the New France stream.

3. The Huguenot question: largely excluded from New France

One of the persistent questions in French Canadian historiography is the role of French Protestants (Huguenots) in the colonization of New France. The answer is paradoxical. Huguenots financed and led the early Atlantic exploration: Samuel de Champlain himself, the founder of Quebec City, was raised in a Protestant family from Brouage in Saintonge and only formally converted to Catholicism in 1603. Pierre Dugua de Mons, who founded Port-Royal in 1604 and chose Champlain as his lieutenant, was an active Huguenot. The two most important port of departure for New France, La Rochelle and Dieppe, were both Protestant cities until the 1620s and remained centers of significant Protestant minorities thereafter.

Yet the official policy of the French Crown, from 1627 onwards, was to forbid Protestants from settling in New France. The Compagnie des Cent-Associes of 1627 explicitly restricted colonization to Catholics. The Edict of Nantes, which had granted limited religious freedom to Huguenots in France since 1598, did not apply to New France. After the revocation of the Edict of Nantes in 1685, when Louis XIV banned Protestantism in France entirely, Huguenot emigration was diverted to the Netherlands, England, Prussia, and the British American colonies (especially South Carolina and New York), not to Quebec. As a result, the Huguenot demographic contribution to French Canada was small and indirect. Some Huguenots converted to Catholicism in order to settle in New France; some came illegally or as soldiers and were tolerated locally; a small number of Huguenot ancestors appear in the BALSAC genealogy of modern Quebec.

The contrast with the Acadian case is sharp. Acadia was administratively more permissive in the early decades, and a substantial fraction of the Razilly and d'Aulnay recruits in the 1630s and 1640s were nominal Catholics but came from Loudunais and Aunis villages with significant Protestant populations. After the 1713 cession to Britain, the Acadians were officially Catholic but had been culturally isolated for two generations from the Catholic-Protestant tensions of metropolitan France. The Acadian gene pool therefore carries a small but real signal from formerly Protestant western French populations, particularly from La Rochelle and the Saintonge hinterland, where the Huguenot tradition was strongest.

4. Three streams, three destinations

The three demographic streams of New France produced three distinct colonial populations, each with its own subsequent history. The St. Lawrence valley population stayed in place after the British Conquest of 1760 and expanded through natural increase into modern French Canada. The Acadians were scattered by the Grand Derangement of 1755 to 1763 and reformed, against all odds, as the Cajuns of Louisiana, the Acadians of New Brunswick (the Maritimes returnees), and a smaller diaspora in Quebec (Gaspe Peninsula) and France (Belle-Ile-en-Mer). The Newfoundland and Saint-Pierre fishing population remained smaller and more seasonal but contributed substantially to specific regions of the Quebec coast (the North Shore, Iles-de-la-Madeleine).

5. The Grand Derangement: the Acadian catastrophe

The deportation of the Acadians between 1755 and 1763 is one of the most thoroughly documented forced population displacements of the early modern Atlantic world. The triggering event was political: the Acadian refusal to swear an unconditional oath of allegiance to the British Crown. The Acadians had lived under British sovereignty since 1713 but had managed, for two generations, to maintain a position of practical neutrality between the British colonial administration and the French Crown. With the outbreak of the Seven Years' War in 1754 and the British fear of a fifth column in the strategically critical Bay of Fundy, the Nova Scotia Council under Governor Charles Lawrence decided in July 1755 to deport the entire Acadian population.

The military operation began at Fort Beausejour in August 1755 and at Grand-Pre and Pisiquit in September. Acadian men were summoned to the village churches and arrested, their farms burned, their livestock confiscated. Families were loaded onto British transport ships and dispersed across multiple destinations to prevent reunification. The historian Naomi Griffiths estimates that 7,000 Acadians were directly deported in the first wave (1755 to 1758), another 3,500 to 5,000 in the second wave (1758 to 1762, after the British capture of Louisbourg and Ile Saint-Jean), and that 3,000 to 5,000 more died from disease, drowning, starvation, or imprisonment during the events. The total demographic loss is estimated between 30 and 60 percent of the pre-1755 Acadian population.

6. The genetics of modern Quebec: still essentially French

Four centuries of demographic isolation could have reshaped the French Canadian gene pool substantially. They did not. The population grew through natural increase from a restricted founder pool, with strong endogamy enforced by religious, linguistic, and geographic factors. The result is a population that is genetically still very close to its source regions in France, with the founder effect visible as increased homozygosity and elevated frequency of certain rare variants, but with no large-scale admixture from non-European sources.

For this article, we analyzed six anonymized Quebec samples (designated Quebec_sample_1 through Quebec_sample_6) on the Global25 PCA, using the Davidski Standard reference panel and comparing them to French regional populations. One additional Quebec sample available in the original dataset was excluded after inspection because the donor's genealogy indicated mixed (non-pure French Canadian) ancestry; the analyses below are based only on the six samples with documented full Quebec ancestry.

Global 25 Europe 1 PCA (Vahaduo). The dark green dots (1000_Quebec) plot the broader 1000 Quebec project cohort. They cluster tightly inside the French regional cloud, surrounded by French_Nord, French_Normandy, French_Paris, French_Alsace and French_Brittany labels, with French_Auvergne immediately below and French_Belgian-Dutch populations to the upper right. The Iberian populations sit to the left of the plot, the British and Irish to the upper right, the Italians to the lower left, and Central European Slavic and Germanic populations to the lower right. The Quebec polygon overlaps the heart of the northern and western French zone with no displacement toward British Isles, Iberian or any non-French cluster, confirming that the average Quebecer remains genetically inside the French cloud four centuries after the founding of the colony.

Three observations stand out. First, the closest matches concentrate on the northern and western French regional populations: French_Nord, French_Poitou-Charentes, French_Normandy, and French_Paris. This is exactly what would be predicted from the historical record of 8,500 founders drawn predominantly from Île-de-France, Normandy, Poitou-Charentes, and the Aunis-Saintonge area. Second, no sample matches a southern French population (French_Provence, French_Occitanie, French_Bigorre) as its closest reference, which is also consistent with the historical record: the south of France contributed almost nothing to the New France stream. Third, the Quebec average sits at a smaller G25 distance from French_Nord than two neighboring French regional populations sit from each other, meaning that the average Quebec individual is, autosomally, indistinguishable from a northern French.

7. The genetics of the Cajuns: closer to Normandy and Brittany than to Paris

The Cajun population is genetically derived from a much narrower founder pool than the Quebec population: roughly 1,000 Acadian founders, filtered through the Grand Derangement, with a second filter applied by the Louisiana resettlement of 1764 to 1785. The result is a founder effect even stronger than the Quebec one, with high homozygosity and elevated frequency of specific founder mutations (such as the USH1C variant for Usher syndrome type I, which is shared between the Acadians of Louisiana, the Acadians of New Brunswick, and the Acadians of Gaspe).

We analyzed five anonymized Cajun samples (Cajun_sample_A through Cajun_sample_E) using the same Global25 methodology. Two of these samples come from individuals with documented 100 percent Cajun ancestry (all four grandparents from the same small Cajun town); the others have mixed Cajun and other French Canadian background.

8. Native American ancestry in Quebec: small but real

One of the persistent questions in French Canadian genetics is the extent of Native American admixture. The French in New France were, on balance, much more willing to intermarry with Indigenous people than the English in the thirteen colonies. The fur trade, dominated by the coureurs des bois (French Canadian woodsmen) and the voyageurs, depended on alliances and marriages with Algonquian, Iroquoian, and Cree partners. The Metis population of the prairies, although mostly post-1815, traces a substantial part of its ancestry to French Canadian fur traders. So there was, demonstrably, a real demographic input from Indigenous populations into the broader French colonial gene pool of North America.

However, when this input is measured directly in the modern Quebec population, it turns out to be small. Bherer et al. 2011 in the American Journal of Physical Anthropology estimated the Native American component at around 1 percent on average across Quebec, with substantial variance between regional populations and between individuals. Jomphe, Lavoie, Moreau, and Labuda (2012) refined this estimate using both genealogical and genomic data and found that approximately 50 percent of contemporary French Canadians have at least one documented Native American ancestor in their genealogy, but that the autosomal contribution from this ancestor has been diluted by 8 to 10 generations of subsequent endogamy to a per-individual range of typically 0 to 5 percent, with a population mean closer to 1 percent.

9. The founder effect inside Quebec: SLSJ, Gaspe Acadians, and Gaspe Loyalists

While the average Quebecer is autosomally close to northern France, the modern Quebec population is not uniform. The Gagnon et al. 2024 study in the European Journal of Human Genetics, using the complete BALSAC genealogy of 665 subjects from eight regional and ethnocultural groups, showed that the Quebec population subdivides into five fine-scale subpopulations that emerged progressively from the 18th century onwards. Two of these subpopulations are particularly distinctive.

10. NNLS modeling with a Mi'kmaq proxy

The geometric position of the Quebec and Cajun population means in Global25 PCA space can be modeled as a non-negative linear combination of source populations using NNLS. For this article we built the model using the ExploreYourDNA panel of French regional averages (which has substantially better sample sizes than the single-point Davidski coordinates: France_Brittany N=17, France_Lower_Normandy N=13, France_Nord-Pas-de-Calais N=13, France_Poitou-Charentes N=10, France_Upper_Normandy N=10, France_Pays_de_la_Loire N=8, and others). For the Indigenous American source we used Canada_400BP, a Canadian ancient DNA sample dated to approximately 1626 CE, which falls in the geographic and temporal window of contact between French settlers and the Mi'kmaq of Acadia (founded 1604), the Algonquin and Wendat of the St. Lawrence valley (Quebec founded 1608), and the other Northeastern Algonquian groups. Canada_400BP is the best available proxy for the Indigenous demographic input into French North America that does not introduce midpoint artifacts from Mesoamerican or Andean populations.

11. The Cajun cultural identity

While the genetic profile of the Cajuns has remained French, their cultural identity has developed into something distinct from both metropolitan French and from Quebec French. Cajun French, spoken by an estimated 150,000 to 200,000 people in Louisiana today, preserves many lexical and grammatical features of 17th and 18th century western French (Poitevin, Saintongeais) that have disappeared from modern continental French. The pronunciation has been influenced by neighboring English and by the Louisiana Creole French of the African American francophone population. The lexicon includes Indigenous, Spanish, and African loan words absent from Quebec French (banquette for sidewalk, lagniappe for bonus, gris-gris for charm).

Cajun music, with its central instruments of the diatonic accordion (introduced in the late 19th century by German settlers along the Cote des Allemands and adopted by Cajun musicians), the fiddle, the triangle, and later the guitar, has become one of the most recognized regional musical traditions of North America. The Cajun accordion (specifically the single-row diatonic accordion in the keys of C, D, or B-flat) defines the sound of the genre, accompanied by French-language lyrics that often deal with rural Louisiana life, love, lamentation, and the historical memory of the Grand Derangement. Closely related is Zydeco, the Creole francophone musical tradition that uses similar instruments but with stronger African American rhythmic input.

Cajun cuisine, which has crossed over into mainstream American food culture since the 1980s, combines French culinary techniques (roux, etouffee, court-bouillon) with Spanish, African, and Indigenous ingredients and methods (gumbo, jambalaya, file powder from sassafras leaves, the holy trinity of bell pepper, onion, and celery). The boudin sausage, the andouille, the tasso ham, and the crawfish boil are recognizable as French country cooking adapted to Louisiana ingredients and tastes. Boudin (the same word as in French, but pronounced "boo-dan" in Louisiana) is a pork-and-rice sausage that combines French charcuterie tradition with the Louisiana use of rice and Cajun spice mixes.

The Cajun identity has been politically and culturally reaffirmed since the 1970s. The CODOFIL (Council for the Development of French in Louisiana) was established in 1968 to promote French-language education in Louisiana public schools, with mixed success. Mardi Gras festivals in Cajun country (Mamou, Eunice, Church Point) differ markedly from the better-known New Orleans Mardi Gras and preserve specifically Cajun rural traditions (the Courir de Mardi Gras, a horseback ride through the countryside to collect ingredients for a communal gumbo). The recognition of Cajun ancestry as a U.S. Census category since 1990 has allowed roughly 600,000 Louisianans to claim it as their primary ethnic identification.

12. The North Shore, Iles-de-la-Madeleine, and the Atlantic fishermen

Beyond the Quebec and Acadian streams, a third French Atlantic stream deserves attention: the seasonal cod fishery of Newfoundland and the Gulf of Saint Lawrence, dominated since the 1500s by Norman, Breton, and Basque fishermen. Although this stream did not produce a continuous large settlement, it left two distinct demographic legacies on the modern Quebec map.

The first is the Iles-de-la-Madeleine (Magdalen Islands), an archipelago in the southern Gulf of Saint Lawrence. The islands were settled permanently after 1763 by Acadian refugees from the Grand Derangement, supplemented by Breton and Norman fishermen who had been using the islands as a seasonal base for over two centuries. The modern Madelinot population retains a recognizable Acadian identity but with stronger Norman-Breton autosomal input than the mainland New Brunswick Acadians.

The second is the eastern North Shore of Quebec, the long stretch of coastline north of the Saint Lawrence estuary running from Sept-Iles to Blanc-Sablon. The Gagnon et al. 2024 European Journal of Human Genetics study notes that the eastern North Shore was settled by "fishermen from Iles-de-la-Madeleine and Gaspe", not by St. Lawrence French Canadians, and that this gives the eastern North Shore population a distinct genetic profile, closer to the Acadian and Magdalen Islands populations than to the mainland Quebec stream. The North Shore subgroup shares more long IBD segments than the SLSJ subgroup, reflecting more recent common ancestors, but fewer short segments, reflecting a narrower founder base.

Saint-Pierre-et-Miquelon, kept by France in the Treaty of Paris of 1763 and again in 1814, remains the only French overseas territory in North America. Its population of around 6,000 traces ancestry to Breton, Norman, and Basque fishermen, with smaller Acadian and Madelinot input. The genetic profile of Saint-Pierrais today is closer to modern Breton and Norman populations than to mainland French Canadians, reflecting the continuous demographic input from western France during the 19th and early 20th centuries when the colony served as the base for the French Atlantic cod fleet.

13. The Scottish soldiers and the Irish famine orphans: post-Conquest admixture into French Canada

The British Conquest of 1760 ended the demographic isolation of New France. From 1760 onwards, a series of British, Scottish, and Irish demographic inputs reached the St. Lawrence valley and the Maritimes, several of which mixed into the French Canadian and Acadian gene pools through marriage and adoption. The two most significant of these inputs are the Highland Scottish soldiers of the 1760s and the Irish famine orphans of 1847. Both are visible in modern French Canadian autosomal data as small but consistent British Isles signals layered on top of the original French founder profile.

Beyond the 1847 orphan cohort, Catholic Irish immigration to Quebec was substantial throughout the 19th century. The 1851 Canadian census recorded roughly 50,000 Irish-born residents in Lower Canada (modern Quebec), a large majority of them Catholic and therefore religiously compatible with French Canadian society. Irish-French marriages, while less common than within-group marriages, accumulated steadily in the urban parishes of Quebec City (Saint-Roch, Saint-Sauveur, Saint-Patrick) and Montreal (Griffintown, Pointe-Saint-Charles, Saint-Henri), as well as in the Outaouais (Aylmer, Buckingham, Gatineau) and the Ottawa Valley lumber camps where Irish and French Canadian workers labored side by side. Surnames like Hurteau (Hurteau, originally probably a phonetic adaptation), Aquin (with some lineages tracing to an Irish ancestor named Hawkins), Riendeau (in some cases from Reardon), and several others document the Irish demographic input through onomastic Francization.

For the Acadians, the equivalent admixture pattern is different. The Acadian deportation of 1755 to 1763 occurred before the Highland Scottish and Irish famine waves reached the Maritimes, and the post-1764 Acadian returnees regrouped in dedicated Acadian villages (Caraquet, Bouctouche, Memramcook, Cheticamp) that remained ethnoreligiously endogamous for several generations. The principal exception is Cheticamp on Cape Breton Island, where the Acadian population coexisted from the 1810s onward with the neighboring Highland Catholic Scots of Inverness County. Modern Cheticamp Acadian families show a slightly elevated Scottish autosomal signal compared to New Brunswick Acadians, consistent with this localized admixture. The Cajuns of Louisiana experienced negligible Irish or Scottish demographic input: the Cajun gene pool was effectively closed by the 1820s once the major Acadian arrival waves ended, and the small Irish immigration into Louisiana of the 1830s to 1860s went mostly to New Orleans rather than to the Acadian parishes.

In autosomal Global25 modeling, this post-Conquest British Isles input is visible as a small Irish or Scottish component in NNLS fits for many modern Quebec individuals, typically in the 0 to 10 percent range, occasionally reaching 20 to 40 percent in specific lineages descending from a documented Irish or Scottish ancestor (a Fraser Highlander progenitor of an 18th century family, or an Irish famine orphan ancestor of a 19th century family). When a Quebecer's NNLS output shows a non-trivial Irish or Scottish component on top of an otherwise French profile, the 19th century BALSAC genealogy usually identifies the ancestor within four to six generations. The Anderson-Trocme et al. 2023 Science study of more than 20,000 Quebec genomes explicitly identifies Irish-derived ancestry in a substantial minority of modern Quebecers, with the strongest signals concentrated in regions of historical Irish settlement (Quebec City, Montreal, the Pontiac and Outaouais regions, the Eastern Townships).

14. The Franco-American emigration: 900,000 Quebecers to New England

Between 1840 and 1930, a major emigration wave took Quebecers south to the textile mills of New England. The economic push factors included rural overpopulation in the older Quebec seigneuries (where partible inheritance had subdivided farms below the level of viability after 200 years of high birth rates) and several crop failures in the 1840s and 1850s. The pull factor was the rapid industrial expansion of New England, which needed cheap labor for its textile, shoe, and paper mills. By 1900, roughly 600,000 Quebec-born people lived in New England; by the peak in 1930, the total Franco-American population (Quebec-born plus their American-born descendants) reached around 900,000.

The Franco-Americans concentrated in specific industrial cities: Lowell, Lawrence, and Fall River in Massachusetts; Manchester and Nashua in New Hampshire; Lewiston and Biddeford in Maine; Woonsocket and Central Falls in Rhode Island. They formed Little Canadas (Petits Canadas), French-speaking Catholic neighborhoods with their own parishes, parochial schools, mutual-aid societies, and newspapers. The Catholic Church played a central role in maintaining French language and identity, with bilingual parishes (the Eglise nationale) often in conflict with the Irish-dominated American Catholic hierarchy.

The French language declined sharply in New England between 1930 and 1980, primarily through the disappearance of bilingual parochial schools and the assimilation pressure of World War II and the post-war economic boom. By 2000, the U.S. Census still identified French and French Canadian as the largest reported ancestry in 50 counties of the United States, mostly in northern New England (especially Maine, where 5 of 16 counties had French Canadian as their plurality ancestry, the highest concentration outside Louisiana). The cultural revival since the 1970s has been driven by university programs (Universite du Maine a Fort-Kent, Universite du Vermont), genealogical interest, and the parallel Quebec sovereigntist movement, which has rekindled awareness of the Franco-American historical legacy.

15. Three transversal lessons

The Franco-American genetic story illustrates three general principles of population history that the modern paleogenetic literature has articulated in different contexts.

First, founder effects preserve source-region ancestry. The 8,500 French settlers of Quebec and the 1,000 Acadian founders did not undergo substantial admixture with the surrounding non-European populations after their arrival, despite four centuries of opportunity. Religion, language, geography, and political organization all conspired to keep the founder gene pool isolated. The modern Quebec and Cajun populations are therefore much closer, autosomally, to their 17th and 18th century French source regions than would be expected from the geographic distance and time depth alone. This is the same principle that explains why modern Mizrahi Jews are still closer to the Iron Age Levant than to their Mesopotamian or Persian hosts, and why modern Sicilians still carry detectable Magna Graecia signal 2,500 years after the founding of Syracuse. Endogamy preserves ancestry.

Second, demographic expansion from a narrow base creates founder-effect substructure. The Saguenay-Lac-Saint-Jean population grew 25-fold between 1861 and 1961 from a few hundred founding families recruited from neighboring Charlevoix. The result is one of the most studied founder effects in human genetics, with specific rare variants reaching 4-fold to 8-fold higher frequencies than in the broader Quebec population. The same applies to the Acadians of Gaspe, the Cajuns of Louisiana, and to a lesser extent the Madelinots of the Iles-de-la-Madeleine. Each of these populations descends from a restricted set of founders followed by demographic isolation and rapid expansion. The pattern reproduces, at smaller scale, what is seen in the Ashkenazi Jews (350 founders, expansion from medieval Rhineland), the Finns (small Neolithic and Bronze Age founders, expansion in the post-glacial period), and the Hutterites and Amish (~400 founders, rapid demographic expansion under endogamy).

Third, political borders are slower than genealogical drift but faster than genetic flow. The political border between French Canada and English Canada was drawn in 1760 by the British Conquest, and the political border between French Acadia and British Nova Scotia in 1713. Two and a half centuries later, the modern French Canadian and modern Acadian populations remain culturally and politically distinct from their Anglophone neighbors. The genetic boundary, however, is even sharper than the political one: French Canadian, Acadian, and Cajun populations have not significantly admixed with the surrounding English, Irish, Scottish, or American populations beyond ordinary individual exceptions. This is the opposite extreme from the Corsican case (politically French since 1768, autosomally Italian) or the British case (politically united since 1707, genetically still subdivided between Anglo-Saxon and Celtic substrate). In French North America, the political, linguistic, religious, and genetic boundaries have remained almost perfectly aligned.

16. G25 coordinates (Global25 scaled)

The following coordinates correspond to the populations and anonymized samples discussed in this article. The seven Quebec samples and five Cajun samples are anonymized public-domain coordinates from contributors to the ExploreYourDNA community. Copy them into Vahaduo, the Davidski Standard G25 Calculator (Calculator 2 on ExploreYourDNA), or the Modern World Regions Mythbuster (Calculator 173) for your own modeling.

Quebec_sample_1,0.127482,0.142174,0.052797,0.024548,0.041238,0.013387,-0.001645,0.001154,0.018203,0.018041,-0.004872,0.000749,-0.014569,-0.002615,0.013301,-0.004243,-0.019036,0.007221,0.009553,-0.005253,0,-0.005317,-0.006409,-0.004579,0.003233
Quebec_sample_2,0.127482,0.136081,0.0445,0.020995,0.034468,0.009203,0.00188,0.002769,0.01084,0.016766,-0.001137,0,-0.013677,-0.004129,0.014115,-0.003978,-0.014473,0.000507,0.000503,-0.004002,-0.003619,0.0115,-0.006162,0.00964,0.000718
Quebec_sample_3,0.12634365,0.142174119,0.052042653,0.01679608,0.043392736,0.007251157,-0.000470021,0.002307596,0.012680478,0.014032181,-0.011854355,0.004196265,-0.005351785,-0.008670228,0.013300589,-0.009281271,-0.01095226,-0.003040526,-0.002388263,-0.007878779,-0.003493835,0.001731138,-0.004806661,0.005904449,0.006586236
Quebec_sample_4,0.127482,0.137096,0.046763,0.028747,0.040007,0.00251,0.003995,0.006923,0.008999,0.020957,-0.002761,0.003747,-0.012636,-0.017616,0.017779,0.01538,0.017863,0.001014,0.000377,0.001876,0.001248,0.004081,-0.002342,0.00976,0.002515
Quebec_sample_5,0.121791,0.137096,0.053551,0.024548,0.041854,0.008646,-0.000235,0.001385,0.008999,0.021686,-0.005846,0.002398,-0.016947,-0.009496,0.015879,0.005436,-0.000913,-0.00038,0.005028,0.002251,-0.001872,0.00507,-0.002342,0.010122,0.007305
Quebec_sample_6,0.134311,0.139128,0.047517,0.031977,0.036622,0.012829,-0.00235,0.002769,0.006954,0.017859,-0.001137,0.001349,-0.009068,-0.013212,0.011129,0.008751,-0.001695,0.000127,0.005028,0.003252,0.006489,0.001978,-0.00037,0.001446,0.000838
Cajun_sample_A,0.127907,0.136810,0.048278,0.018096,0.038363,0.006940,0.000952,0.001147,0.010746,0.017336,-0.003757,0.005541,-0.012298,-0.002680,0.004248,0.002105,0.000096,0.000537,0.003230,-0.002124,0.000204,-0.000072,0.000398,0.004929,-0.000553
Cajun_sample_B,0.128992,0.134808,0.057201,0.035828,0.040889,0.012479,0.001172,0.003136,0.007876,0.009930,-0.004714,0.005330,-0.013687,-0.008838,0.017959,0.003400,-0.006770,0.001060,0.000417,0.002151,0.004823,0.000430,-0.000681,0.006271,0.000869
Cajun_sample_C,0.128926,0.134906,0.055467,0.027736,0.041985,0.008079,-0.002629,-0.001771,0.011326,0.016459,-0.003560,0.005853,-0.012978,-0.010042,0.010267,0.001761,-0.004979,0.001755,0.002582,-0.001813,0.001208,0.002148,-0.000878,0.006986,-0.000541
Cajun_sample_D,0.126975,0.133709,0.048072,0.027184,0.036082,0.010977,-0.000504,-0.000113,0.008457,0.013529,-0.003935,0.005616,-0.012531,-0.006574,0.009604,0.000563,-0.003782,0.000625,0.001718,-0.000843,0.001787,0.001141,0.000065,0.006830,-0.000362
Cajun_sample_E,0.136588,0.126941,0.046009,0.017119,0.040315,0.013387,0.003055,-0.002769,0.012885,0.018770,0.003085,0.001948,-0.017691,-0.017478,0.003393,0.014585,0.014342,-0.000633,0.005908,0.010255,0.001622,-0.002720,0.000493,0.009037,-0.000958
French,0.129086,0.142174,0.049857,0.021157,0.042162,0.005577,0.000587,0.003923,0.012066,0.022416,-0.00471,0.006144,-0.013479,-0.009496,0.011944,0.004243,-0.003912,0.000887,0.000628,-0.000625,0.004118,0.001113,-0.002342,0.001928,-0.000539
French_Poitou-Charentes,0.130024,0.140644,0.050431,0.024548,0.038423,0.008911,0.002115,0.003923,0.006954,0.011469,-0.005846,0.005995,-0.011382,-0.00963,0.011536,0.003448,-0.005215,0.001774,0.001257,0.000625,0.004492,0.001978,-0.001602,0.007471,-0.000419
French_Normandy,0.131466,0.139128,0.0535,0.029102,0.04231,0.012999,0.003586,0.001577,0.008373,0.011104,-0.005329,0.004146,-0.009741,-0.008594,0.013209,0.004552,-0.003259,0.000823,0.001131,-0.001876,0.005364,0.002411,-0.000123,0.005784,-0.001725
French_Brittany,0.131466,0.13834,0.05785,0.039285,0.039169,0.015813,0.003155,0.004211,0.008186,0.00949,-0.005131,0.00559,-0.014368,-0.013102,0.018343,0.004399,-0.007302,0.00128,-0.000462,0.001773,0.004467,0.001787,-0.001254,0.010547,0.000659
French_Nord,0.128275,0.140543,0.051357,0.025605,0.038273,0.008891,0.001097,0.00442,0.008373,0.012016,-0.003484,0.004033,-0.010861,-0.008182,0.011199,0.002543,-0.004607,0.002227,0.004095,0.001031,0.002133,0.001525,-0.001572,0.007471,0.000014
French_Paris,0.127171,0.141436,0.050431,0.02399,0.040903,0.009305,0.002799,0.005454,0.011602,0.018174,-0.007706,0.006812,-0.012906,-0.010384,0.01377,0.006063,-0.001825,0.004664,0.002708,-0.000978,0.002201,0.003575,-0.001232,0.011141,-0.001905
French_Seine-Maritime,0.136019,0.137096,0.045254,0.029555,0.039084,0.016733,0.00423,-0.000692,0.003988,0.006014,-0.003735,0.007493,-0.007582,-0.001651,0.014251,0.003514,-0.007953,-0.002344,0.000943,-0.005002,0.003931,0.005503,0.000863,0.004278,-0.004491
French_Pas-de-Calais,0.127861,0.140481,0.054305,0.026809,0.042162,0.012736,0.004152,0.001308,0.008522,0.012453,-0.008011,0.002198,-0.01001,-0.012019,0.013663,0.008132,-0.000478,0.001816,-0.003645,0.004252,0.009982,0.001443,-0.002547,0.005904,-0.001437
French_Alsace,0.127311,0.140372,0.050317,0.022432,0.038423,0.008911,0.00292,0.004875,0.006852,0.010679,-0.003134,0.004578,-0.009444,-0.00417,0.008561,0.003066,-0.004893,0.002439,0.003243,-0.000716,0.002764,0.001156,-0.001322,0.007137,-0.000314
French_Auvergne,0.125416,0.144656,0.04742,0.012992,0.043472,0.003997,-0.000339,0.002513,0.015407,0.022172,-0.002466,0.007355,-0.013969,-0.009669,0.008299,0.001483,-0.000787,0.001497,0.003073,-0.000213,0.001858,0.003737,-0.002282,0.001816,-0.000089
French_Occitanie,0.127039,0.144883,0.048879,0.017908,0.043376,0.003416,0.000522,0.003891,0.014856,0.023589,-0.003288,0.006582,-0.015044,-0.009458,0.010737,0.002567,-0.003709,0.002484,0.001425,0.000045,0.003671,0.002446,-0.00255,0.001767,0.000422
French_Provence,0.121925,0.143847,0.036891,0.005358,0.036858,0.00233,0.002267,0.003638,0.010058,0.020453,-0.003869,0.007211,-0.012138,-0.010961,0.005956,0.003174,0.001097,0.002809,0.001775,-0.001515,0.001541,0.002735,0.000355,0.005444,0.000035
Basque_French,0.128051,0.152025,0.055173,0.012823,0.056411,0.00251,-0.00141,0.003323,0.030597,0.041204,-0.009272,0.010341,-0.020976,-0.014024,0.013219,-0.001936,-0.011917,0.003028,-0.000716,-0.004415,0.010157,0.002485,-0.00864,-0.00917,0.000072
Spanish_Cataluna,0.114582,0.146236,0.045883,0.002369,0.047188,0,-0.002037,0.002384,0.022361,0.030494,-0.001895,0.008592,-0.016006,-0.010643,0.008867,0.001591,-0.000652,-0.001647,-0.001131,-0.000959,0.006197,-0.005729,-0.003903,-0.001928,0.000958
Canada_400BP,0.052359,-0.319892,0.120679,0.091409,-0.10125,0.004183,-0.208689,-0.249682,-0.00225,-0.026789,-0.000974,-0.002548,-0.003717,0.018441,-0.000407,0.021612,0.008996,0.012289,0.00264,-0.00988,-0.006364,-0.01014,-0.009244,0.005422,0.009819

17. Conclusion

The French presence in North America began with two small founding pulses: 8,500 settlers in the St. Lawrence valley between 1608 and 1760, and around 1,000 founders in Acadia between 1604 and 1755. Four centuries later, more than 11 million descendants of these founders live in Quebec, the Acadian Maritimes, Louisiana, New England, and elsewhere. Their cultural identity has diversified dramatically: French Canadians of Quebec, Acadians of New Brunswick, Cajuns of Louisiana, Madelinots of the Iles-de-la-Madeleine, Saint-Pierrais of the last French overseas territory in North America, Franco-Americans of Maine and Vermont. Their political fortunes have been wildly different, from the conquered but persistent French Canadians of the St. Lawrence to the scattered and reborn Acadians of the diaspora to the assimilated Franco-Americans of New England.

Their genetic profile, however, has remained remarkably uniform. On the Global25 PCA, the average modern Quebecer sits at distance 0.0107 from French_Nord, and the average Cajun at 0.0155 from France_Pays_de_la_Loire. These are smaller than the distance between two neighboring French regions. The same northern and western French source regions (Normandy, Poitou-Charentes, Île-de-France, Picardy, Brittany) that the historical record identifies as the principal contributors to the New France stream are still the closest matches in autosomal space today. The founder effect is visible only as elevated frequency of specific rare alleles within the population (USH1C in Acadians and Cajuns, the Charlevoix-Saguenay variants in SLSJ, several others) and as fine-scale structure between subpopulations (SLSJ, Gaspe Acadians, Gaspe Loyalists, Madelinots, North Shore eastern fishermen, Charlevoix descendants of Highland soldiers). The post-Conquest admixture from Highland Scottish soldiers (1760s) and Irish famine orphans (1847) adds a small but detectable British Isles signal to many French Canadian families, and a small Mi'kmaq signal sits in the Cajun gene pool from the 17th and 18th century Acadian-Mi'kmaq marriages. None of these inputs has displaced the dominant French founder profile.

What the genetic story confirms is the resilience of the founding pulse. Eight and a half thousand French settlers, dropped in a frozen valley in 1608, multiplied to eight million descendants. One thousand Acadian founders, deported, scattered, and reborn in Louisiana, are still autosomally Norman and Poitevin today. The Atlantic crossing, the harsh winters, the British Conquest, the Grand Derangement, the Cajun cultural reconstruction, the New England exodus, the linguistic assimilation, none of these events have erased the original signal. The Cajun bayou, the Quebec habitant, and the Acadian fisherman of the Bay of Fundy all carry, in their autosomal DNA, the same restricted slice of 17th century western France that crossed the ocean on the ships of Champlain, Razilly, d'Aulnay, and the Filles du Roi.

18. References

1. Anderson-Trocme, L., Nelson, D., Zabad, S., Diaz-Papkovich, A., Baya, N., Touvier, M., Jeffery, B., Dina, C., Vezina, H., Kelleher, J., Gravel, S. (2023). On the genes, genealogies, and geographies of Quebec. Science, 380(6647), 849-855. DOI: 10.1126/science.add5300 BALSAC Quebec
2. Gagnon, L., Moreau, C., Laprise, C., Vezina, H., Girard, S. L. (2024). Deciphering the genetic structure of the Quebec founder population using genealogies. European Journal of Human Genetics, 32(1), 91-97. DOI: 10.1038/s41431-023-01356-2 Genealogy SLSJ Gaspe Acadians
3. Gagnon, L., Moreau, C., Laprise, C., Girard, S. L. (2024). Fine-scale genetic structure and rare variant frequencies. PLOS ONE, 19(11), e0313133. DOI: 10.1371/journal.pone.0313133 USH1C Rare variants
4. Roy-Gagnon, M. H., Moreau, C., Bherer, C., St-Onge, P., Sinnett, D., Laprise, C., Vezina, H., Labuda, D. (2011). Genomic and genealogical investigation of the French Canadian founder population structure. Human Genetics, 129(5), 521-531. DOI: 10.1007/s00439-010-0945-x Quebec founder structure
5. Bherer, C., Labuda, D., Roy-Gagnon, M. H., Houde, L., Tremblay, M., Vezina, H. (2011). Admixed ancestry and stratification of Quebec regional populations. American Journal of Physical Anthropology, 144(3), 432-441. DOI: 10.1002/ajpa.21424 Native American admixture
6. Jomphe, M., Lavoie, E. M., Moreau, C., Labuda, D. (2012). L'apport des donnees genetiques a la mesure genealogique des origines amerindiennes des Canadiens francais. Cahiers Quebecois de Demographie, 41, 87-105. Indigenous admixture
7. Moreau, C., Vezina, H., Yotova, V., Hamon, R., Knijff, P. D., Sinnett, D., Labuda, D. (2009). Genetic heterogeneity in regional populations of Quebec, parental lineages in the Gaspe Peninsula. American Journal of Physical Anthropology, 139(4), 512-522. DOI: 10.1002/ajpa.21012 Gaspe
8. Ebermann, I., Lopez, I., Bitner-Glindzicz, M., Brown, C., Koenekoop, R. K., Bolz, H. J. (2007). Deafblindness in French Canadians from Quebec: a predominant founder mutation in the USH1C gene provides the first genetic link with the Acadian population. Genome Biology, 8(4), R47. DOI: 10.1186/gb-2007-8-4-r47 USH1C founder Acadian-Quebec link
9. Robichaud, P. P., Allain, E. P., Belbraouet, S., Bherer, C., Mamelona, J., Harquail, J., et al. (2022). Pathogenic variants carrier screening in New Brunswick: Acadians reveal high carrier frequency for multiple genetic disorders. BMC Medical Genomics, 15(1), 98. DOI: 10.1186/s12920-022-01249-1 New Brunswick Acadians
10. Gauvin, H., Moreau, C., Lefebvre, J. F., Laprise, C., Vezina, H., Labuda, D., Roy-Gagnon, M. H. (2014). Genome-wide patterns of identity-by-descent sharing in the French Canadian founder population. European Journal of Human Genetics, 22(6), 814-821. DOI: 10.1038/ejhg.2013.227 IBD
11. Scriver, C. R. (2001). Human Genetics: Lessons from Quebec Populations. Annual Review of Genomics and Human Genetics, 2, 69-101. DOI: 10.1146/annurev.genom.2.1.69 Founder effect
12. Laberge, A. M., Michaud, J., Richter, A., Lemyre, E., Lambert, M., Brais, B., Mitchell, G. A. (2005). Population history and its impact on medical genetics in Quebec. Clinical Genetics, 68(4), 287-301. DOI: 10.1111/j.1399-0004.2005.00497.x Medical genetics Quebec
13. Charbonneau, H., Desjardins, B., Legare, J., Denis, H. (2000). The population of the St-Lawrence Valley, 1608-1760. In: A Population History of North America. Cambridge University Press, pp. 99-142. Historical demography
14. Grace, R. J. (1993). The Irish in Quebec: An Introduction to the Historiography. Institut quebecois de recherche sur la culture. Irish immigration Quebec
15. Marianna O'Gallagher (1984). Grosse Ile: Gateway to Canada 1832-1937. Carraig Books. Documents the Grosse-Ile quarantine station, the 1847 typhus catastrophe, and the adoption of Irish famine orphans by French Canadian families. Irish orphans Grosse-Ile
16. Bumsted, J. M. (1982). The People's Clearance: Highland Emigration to British North America 1770-1815. Edinburgh University Press / University of Manitoba Press. Documents the Highland Scottish emigration to Cape Breton, Antigonish County, and the surrounding regions where Highland Scots Catholics settled adjacent to Acadian communities. Highland Scots Cape Breton
17. Harper, M. (2003). Adventurers and Exiles: The Great Scottish Exodus. Profile Books. Scottish emigration Canada
18. Charbonneau, H., Robert, N. (1987). The French origins of the Canadian population, 1608-1759. In: Historical Atlas of Canada, Volume I. University of Toronto Press, plate 45. Historical demography
19. Desjardins, M., Frenette, Y., Belanger, J. (1999). Histoire de la Gaspesie. Editions de l'IQRC, Sainte-Foy, Quebec. 797 p. Gaspe history
20. Pouyez, C., Lavoie, Y. (1983). Les Saguenayens. Introduction a l'histoire des populations du Saguenay. Presses de l'Universite du Quebec. 386 p. SLSJ history
21. Griffiths, N. E. S. (2005). From Migrant to Acadian: A North American Border People, 1604-1755. McGill-Queen's University Press. Acadian history
22. Brasseaux, C. A. (1987). The Founding of New Acadia: The Beginnings of Acadian Life in Louisiana, 1765-1803. Louisiana State University Press. Cajun foundation
23. Davidski, A. (ongoing). Global25 PCA modern population averages, scaled coordinates. Eurogenes Blog. Reference panel used for all G25 distances and NNLS models in this article. eurogenes.blogspot.com G25 panel
24. BALSAC (ongoing). BALSAC parish-record genealogical database, Universite du Quebec a Chicoutimi. balsac.uqac.ca Genealogy