Genetic and morphological variation in two littorinid gastropods: evidence for recent population expansions along the East African coast |
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Authors: | Sara E. Silva Inês C. Silva Carolina Madeira Rose Sallema Octávio S. Paulo José Paula |
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Affiliation: | 1. Computational Biology and Population Genomics Group, Centro de Biologia Ambiental, Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, , 1749‐016 Lisboa, Portugal;2. Centro de Oceanografia, Laboratório Marítimo da Guia, Faculdade de Ciências da Universidade de Lisboa, , 2750‐374 Cascais, Portugal;3. National Environment Management Council, , Dar es Salaam, Tanzania |
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Abstract: | In marine species, population diversity and differentiation is affected by the population history and by the complex interaction between oceanographic dynamics and ecological traits. In the present study, we examined two species of marine gastropods (the mangrove periwinkle Littoraria scabra and the rocky shore Littoraria glabrata) along the East African coast, using both genetic and geometric morphometric methods. We report a greater variation of shell shape in L. scabra compared to the slightly smaller variation in L. glabrata. This variation was probably associated with variation of environmental factors along the coast, such as temperature and hydrodynamics. Despite morphological variation, we found low mitochondrial genetic differentiation among samples from different localities for both species, which is probably a consequence of the ongoing gene flow during the free‐swimming larval stage of these gastropods. Additionally, high levels of haplotype diversity, low nucleotide diversity, and ‘star‐like’ genealogies were found in both species. These observations and the results from mismatch distributions, indicate a possible signature of recent population expansions in both species, which probably started during interglacial periods of the Pleistocene and led to the colonization of the Indian Ocean coast. © 2013 The Linnean Society of London |
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Keywords: | haplotypes Littoraria glabrata Littoraria scabra local adaptation mtDNA population expansion shell morphometrics Western Indian Ocean |
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