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I have family living in the Caribbean, they specifically reside on the island of Grenada. And I regularly go down to visit them. Given that the many islands in Caribbean functioned as pit stops for the slave trade, I’ve been curious about the demographics, history, and genetics of Grenada. Based off of cursory observations, the majority of the population is of African decent — but there are people from Europe, India, the Middle East and East Asia living there as well. I’ve seen very few mix, marry and reproduce. Instead, most choose to live in their respective groups.

An illustration of a Carib Indian family by John Gabriel Stedman

An illustration of a Carib Indian family by John Gabriel Stedman

Prior to European contact in 1498 by Christopher Columbus, Grenada was inhabited by Carib and Arawak peoples, both originating from Central/South America. The Arawak preceded the Caribs. It is believed they first occupied the Caribbean islands somewhere around 100-200 A.D. The Caribs came around much later — about 100 to 150 years before Columbus. They were very hostile compared to the Arawak and killed many Arawak. Those who were spared were enslaved. The Caribs also prevented settlement of Grenada by Europeans for 150 or so years.

The English tried and failed in 1609. The French first gave it a shot in 1638 and biffed it. It was not until 1650 that another French attempt, this time from a nearby island, Martinique, established a permanent presence in Grenada. Not surprisingly, the Carib did not welcome the French colony. They launched a series of battles and lost. They were determined not to submit to French rule and ultimately the last surviving Caribs jumped to their death off a precipice in the north of the island.

Some of the other islands in the Caribbean, like Puerto Rico and Cuba, share a similar history. A primary population, of Arawaks/Taínos displaced by another indigenous population — ultimately to be eradicated by European contact and pathogens. One would suspect that there was not much admixture because of the rapid mortality.

Today, Dienekes shared a paper investigating the genetic diversity of modern Cuba — an island that originally had Arawak people, then Ciboney people, and ultimately African and European slaves and colonists. There are some pretty surprising results.

The paper, “Genetic origin, admixture, and asymmetry in maternal and paternal human lineages in Cuba,” is published in the open access journal BMC Evolutionary Biology. The authors of the paper sequenced and analyzed the HSV I and 5 SNPs in the mitochondrial genome of 245 Cuban individuals. They also seuqenced and analyzed 40 SNPs on the Y-Chromosome of of 132 Cuban males. Their results indicate that the,

“Native American contribution to present-day Cubans accounted for 33% of the maternal lineages, whereas Africa and Eurasia contributed 45% and 22% of the lineages, respectively. This Native American substrate in Cuba cannot be traced back to a single origin within the American continent, as previously suggested by ancient DNA analyses. Strikingly, no Native American lineages were found for the Y-chromosome, for which the Eurasian and African contributions were around 80% and 20%, respectively.”

Razib thinks that the the high percentage of Native American footprint in the modern day Cuban mitochondrial gene pool is because admixture occurred very early on. Makes sense, early European conquistadors and colonists that inhabited Cuba, were most likely straight males interested in the triumph of new land, riches, and flesh.

But, does this genetic analysis of Cubuan populations have any tangents to other Caribbean islands? Razib linked up another paper, published in American Journal of Physical Anthropology, which investigated Puerto Rican mitochondrial diversity. The authors of the paper, “Reconstructing the population history of Puerto Rico by means of mtDNA phylogeographic analysis,” sequenced and analyzed only the mitochondrial genome of 800 individuals. They were able to fish out that 61.3% of Puerto Rican mtDNA comes is of  Amerindian ancestry. Sub-Saharan African and West Eurasian mitochondrial signatures were found in much less degrees, 27.2% and 11.5% respectively.

Both studies show that on these two islands, there is a substantial mitochondrial contribution from indigenous pre-Columbian populations in modern day populations. Dienekes suggests that the reason why there isn’t a substantial Y-chromosome contribution is that Y chromosome diversity within an already settled territory was wiped out, citing that, “new pathogens or a technological differential between colonists and natives,” are two possibilities.

I disagree with the first half of his statement, new pathogens are for the most part indiscriminate of sex. Technological differences, however, could have manifested in less indigenous males, especially after battles. That, coupled with the accounts of rape and pillage by European settlers, it seems like a more understandable reason to why we see such high Amerindian mitochondrial and European Y-chromosome signatures.

    Mendizabal, I., Sandoval, K., Berniell-Lee, G., Calafell, F., Salas, A., Martinez-Fuentes, A., Comas, D. (2008). Genetic origin, admixture, and asymmetry in maternal and paternal human lineages in Cuba. BMC Evolutionary Biology, 8(1), 213. DOI: 10.1186/1471-2148-8-213
    Martínez-Cruzado, J.C., Toro-Labrador, G., Viera-Vera, J., Rivera-Vega, M.Y., Startek, J., Latorre-Esteves, M., Román-Colón, A., Rivera-Torres, R., Navarro-Millán, I.Y., Gómez-Sánchez, E., Caro-González, H.Y., Valencia-Rivera, P. (2005). Reconstructing the population history of Puerto Rico by means of mtDNA phylogeographic analysis. American Journal of Physical Anthropology, 128(1), 131-155. DOI: 10.1002/ajpa.20108