title: Mitochondrial DNA Variation Reveals a Sharp Genetic Break within the Distribution of the Blue Land Crab Cardisoma guanhumi in the Western Central Atlantic.
abstract: The blue land crab Cardisoma guanhumi is widely distributed throughout tropical and subtropical estuarine regions in the Western Central Atlantic (WCA). Patterns of population genetic structure and historical demographics of the species were assessed by mtDNA control region sequence analysis to examine the connectivity among five populations (n = 97) within the region for future conservation strategies and decision-making of fishery management. A total of 234 polymorphic nucleotides were revealed within the sequence region, which have defined 93 distinct haplotypes. No dominant mtDNA haplotypes were found but instead a distribution of a few low-frequency recurrent haplotypes with a large number of singletons. A NJ-tree and a median-joining haplotype network revealed two distinct clusters, corresponding to individuals from estuaries located along the Caribbean Sea and Brazilian waters, respectively. AMOVA and FST statistics supported the hypothesis that two main geographic regions exists. Phylogeographical discontinuity was further demonstrated by the Bayesian assignment analysis and a significant pattern of isolation-by-distance. Additionally, tests of neutral evolution and analysis of mismatch distribution indicate a complex demographic history in the WCA, which corresponds to bottleneck and subsequent population growth. Overall, a sharp genetic break between Caribbean and Brazilian populations raised concerns over the conservation status of the blue land crab.
authors: Molecular Biology & Biotechnology Laboratory, EMBRAPA Meio-Norte, CP 01, Teresina, PI 64049-550, Brazil. rosiax2012@gmail.com.
authors: Maria Rosimere Xavier
authors: MR
authors: Amaral
authors: Department of Biology, University of Nebraska at Kearney, Kearney, NE 68849, USA. albrechtm@unk.edu.
authors: Marc
authors: M
authors: Albrecht
authors: National Park Service, 18001 Old Cutler Bay Rd Suite 419, Palmetto Bay, FL 33190, USA. mckinleyas@lopers.unk.edu.
authors: Alan Shane
authors: AS
authors: McKinley
authors: Molecular Biology & Biotechnology Laboratory, EMBRAPA Meio-Norte, CP 01, Teresina, PI 64049-550, Brazil. dri_bio_uespi@yahoo.com.br.
authors: Adriana Márcia Ferreira
authors: AM
authors: de Carvalho
authors: Department of Zootechny, Universidade Federal do Piauí, Bom Jesus, PI 64900-000, Brazil. sevzoo@yahoo.com.br.
authors: Severino Cavalcante
authors: SC
authors: de Sousa Junior
authors: Molecular Biology & Biotechnology Laboratory, EMBRAPA Meio-Norte, CP 01, Teresina, PI 64049-550, Brazil. fabio.diniz@embrapa.br.
authors: Fabio Mendonça
authors: FM
authors: Diniz
mesh_terms: D000818:Animals; D001267:Atlantic Ocean; D001483:Base Sequence; D001499:Bayes Theorem; D003386:Brachyura / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics*; D014644:Genetic Variation; D005828:Genetics, Population; D006239:Haplotypes / Q000235:genetics; D010802:Phylogeny; D018401:Sample Size
chemical_list: D004272:DNA, Mitochondrial
keywords: brachyuran crabs; control region; genetic diversity; mtDNA; phylogeography; population structure; sequencing