Phylogeography of the Turks Island Boa, Chilabothrus chrysogaster

Hailey Wunder

Biology

R. Graham Reynolds

The Turks Island Boa is the oldest cladogenically distinct lineage of the extant Lucayan boas. It is represented by two subspecies- The Turks Island Boa (Chilabothrus chrysogaster chrysogaster), found in the Turks and Caicos Islands, and the Inagua boa (Chilabothrus chrysogaster relicquus), found in the Bahamas. The Turks Island Boa is extensively studied in Southern Caicos, especially on Big Ambergris Cay. The Turks Island Boa is found on both the Turks and Caicos banks, which are separated by the ~20km Turks Island Passage and have never been connected. A study from 2011 suggests that there is shallow genetic divergence across the two banks, finding a maximum of seven mutational steps between populations of boas on the two banks (Reynolds 2012),. However, that study was limited by having only three samples from the Turks Bank and using only a fraction of a mitochondrial locus. In 2022, a new population of boas was discovered on the Turks Bank, which afforded the opportunity to gain greater insight into population genetic diversity and divergence across the Turks and Caicos banks. I sequenced 30 individuals at an 1077bp mitochondrial locus, including 12 new individuals from the Turks bank. I then aligned these new sequences with an expanded dataset from Reynolds et al. (2011),, and conducted phylogeographic analysis using the package ape in R. I found conclusive evidence of a distinct Turks Bank lineage of boas that is 1.58),, divergent from the Caicos Bank. But I also found that there is a nearly equal divergence across the Caicos Bank,suggesting that genetic divergence is not exclusive to each bank. These data are particularly important as reintroduction programs are designed for boas in the Turks and Caicos Islands.

Jan-9-2024