Early events in speciation: Cryptic species of Drosophila aldrichi |
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Authors: | Cynthia Castro Vargas Maxi Polihronakis Richmond Mariana Ramirez Loustalot Laclette Therese Ann Markow |
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Affiliation: | 1. Laboratorio Nacional de la Genomica de Biodiversidad, CINVESTAV, Irapuato, Guanajuato, Mexico;2. Division of Biological Sciences, University of California at San Diego, La Jolla, CA, USA |
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Abstract: | Understanding the earliest events in speciation remains a major challenge in evolutionary biology. Thus identifying species whose populations are beginning to diverge can provide useful systems to study the process of speciation. Drosophila aldrichi, a cactophilic fruit fly species with a broad distribution in North America, has long been assumed to be a single species owing to its morphological uniformity. While previous reports either of genetic divergence or reproductive isolation among different D. aldrichi strains have hinted at the existence of cryptic species, the evolutionary relationships of this species across its range have not been thoroughly investigated. Here we show that D. aldrichi actually is paraphyletic with respect to its closest relative, Drosophila wheeleri, and that divergent D. aldrichi lineages show complete hybrid male sterility when crossed. Our data support the interpretation that there are at least two species of D. aldrichi, making these flies particularly attractive for studies of speciation in an ecological and geographical context. |
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Keywords: | cryptic species
Drosophila aldrichi
Drosophila wheeleri
Mexico phylogenetic relationships |
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