Population history of the Caribbean (Moreno-Estrada et al. 2013)

The placement of Caribbeans on a European "genetic map" is fairly interesting, as they appear to be "ultra-Iberian" (on the far left). The authors invoke drift as an explanation, which makes sense, given that a small portion of the Iberian gene pool entered into the composition of these populations.

On the other hand, it'd be nice to have Iberian data from a few centuries ago, to make sure, since Iberia, being a part of Europe may have had the opportunity to "right-shift" during the last few centuries due to gene flow, and even if it didn't there is a chance that gene flow within Iberia may have dulled population differentiation, while immigration to the Caribbean may not have originated from all parts of Iberia equally (and as I've shown, there is substantial population structure in Iberia down to this day).

arXiv:1306.0558 [q-bio.PE]

Reconstructing the Population Genetic History of the Caribbean

Andres Moreno-Estrada et al.

The Caribbean basin is home to some of the most complex interactions in recent history among previously diverged human populations. Here, by making use of genome-wide SNP array data, we characterize ancestral components of Caribbean populations on a sub-continental level and unveil fine-scale patterns of population structure distinguishing insular from mainland Caribbean populations as well as from other Hispanic/Latino groups. We provide genetic evidence for an inland South American origin of the Native American component in island populations and for extensive pre-Columbian gene flow across the Caribbean basin. The Caribbean-derived European component shows significant differentiation from parental Iberian populations, presumably as a result of founder effects during the colonization of the New World. Based on demographic models, we reconstruct the complex population history of the Caribbean since the onset of continental admixture. We find that insular populations are best modeled as mixtures absorbing two pulses of African migrants, coinciding with early and maximum activity stages of the transatlantic slave trade. These two pulses appear to have originated in different regions within West Africa, imprinting two distinguishable signatures in present day Afro-Caribbean genomes and shedding light on the genetic impact of the dynamics occurring during the slave trade in the Caribbean.

Link