During this semester, of 60 indigenous samples amplified and purified, 48 were sequenced and compared to the Cambridge Reference Sequence, showing that 27 (57%), 1 (2%), 17 (35%), and 3 (6%) belonged to haplogroups A, B, C, and D, respectively. Thus, the haplogroup distribution in the Dominican Republic is similar to Puerto Rico, where the haplogroup frequencies are 52%, 9%, 36% and 4%. However, median network analyses of the main haplogroups (A and C) show distinct lineages for Puerto Rico and the Dominican Republic, suggesting different origins. Furthermore, a geographic partition can be described for the Dominican Republic, separating the Cibao region from the southwest-to-southeast regions. These results suggest disparate origins and restricted maternally mediated gene flow between geographic regions in small parts of these Antillean islands.
Based on mtDNA data, we have found very little relationship between pre-Columbian Amerindians of Puerto Rico and Hispaniola. Our goal now will be to reach a more precise estimate of the time of arrival of founder females for each island and their continental origin. This will require a bigger sample from each island and collaborations with colleagues in the American continent to identify mtDNAs closely related to the lineages found in the Antilles. I’ve achieved as much as I wanted in the research experience for this semester.
