Using ultraconserved elements (UCEs) to explore evolutionary relationships in Butorides herons
By: Ezra Mendales
Department: Biology
Faculty Advisor: Dr. Jaime Chaves and Dr. Jack Dumbacher (CAS)
Herons (family: Ardeidae) are found across most regions in the world with at least 17 recognized genera and over 60 species. Despite their widespread distribution, few studies have examined the phylogenomic relationships at the species level (Kushlan & Hancock 2005). As a result, several genera lack well-resolved phylogenetic assessments tampering further taxonomic characterization. This is particularly important in species with wide geographic distributions where undescribed diversity (or present subspecific designations) might be overlooked by the lack of detailed genetic assessment.
The genus Butorides is a relatively small genus of herons that corresponds to the previously described model. Two species are currently recognized within this genus (Striated and Green Herons) and their phylogenetic assessment of these two groups have never been confirmed. The Green Heron (B. virescens) is found throughout the Americas and the Caribbean with four subspecies currently recognized. The Striated Heron (B. striata) is currently separated in ca. 22 subspecies found globally in tropical to subtropical environments with continuous distribution on large expanses of land masses (e.g. South America, Africa) as well as with restricted distributions across several islands (e.g. Indonesia, Pacific). The most recognized subspecies within this group is the endemic Galapagos Lava Heron (B. striata sundevalli). This and other subspecies have been classified solely from morphology and geography.
The use of ultraconserved elements (UCEs) have become popular in recent years for phylogenetic analysis. UCEs are both used for deep divergent splits denoted in regions with little variation among species as well as shallow differentiation in younger groups obtained from flanking regions outside the UCEs (Faircloth et al. 2012). The generation of well-resolved phylogenies based on thousands of loci should confidently determine the deep evolutionary relationships in this genus as well as taxonomically categorize cryptically diverged populations.