Using Selected Gene Regions to Find Rapidly Evolving DNA Sequences of Closely Related Species of the Genus Columnea
James F. Smith
Knowing evolutionary relationships among species can improve our understanding of many biological functions. Within the past thirty years, molecular data has changed how these evolutionary relationships are determined and has made molecular phylogenetics an important discipline in biology. The standard in phylogenetic research has been to use DNA sequences to compare genetic variation in gene regions. When attempting to resolve phylogenetic relationships between species, common gene regions known to show variation are the nuclear ribosomal ITS regions and the chloroplast DNA regions, rpl32-trnL, and psbA-trnH spacers. Unfortunately, in the genus Columnea these gene regions have not given sufficient variation to resolve relationships among closely related species. Certain low-copy gene regions have been shown to rapidly evolve and provide supportive variation in other genera. In this study, we examined the feasibility of four low-copy nuclear gene regions and one chloroplast region for phylogenetic comparison across six species using PCR, gel analysis, and DNA sequencing. The utility of these gene regions on phylogenetic analyses was assessed and compared to the results for the aforementioned regions by pairwise percent differences and percent phylogenetically informative characters. The results of these comparisons will minimize time and resources needed to resolve phylogenetic relationships in the genus Columnea.
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