Genetic Differences Within and Between Species of Deep-Sea Crabs (Chaceon) From the North Atlantic Ocean

Abstract

The deep-sea red crab Chaceon quinquedens is a commercially important crustacean on the Atlantic continental shelf and slope of North America. To assess genetic subdivision in C. quinquedens, we examined the nucleotide sequence of the mitochondrial 16S rDNA gene and the internal transcribed spacers (ITS) of the nuclear ribosomal repeat in samples from southern New England and the Gulf of Mexico. We compared those data to sequences from two congeners, a sympatric species from the Florida coast, C. fenneri, and an allopatric eastern Atlantic species, C. affinis. The 16S rDNA data consisted of 379 aligned nucleotides obtained from 37 individuals. The greatest genetic difference among geographical groups or nominal species was between C. quinquedens from southern New England and C. quinquedens from the Gulf of Mexico. Haplotypes from these two groups had a minimum of 10 differences. All 11 C. fenneri samples matched the most common haplotype found in C. quinquedens from the Gulf of Mexico, and this haplotype was not detected in C. quinquedens from southern New England. The three haplotypes of C. affinis were unique to that recognized species, but those haplotypes differed only slightly from those of C. fenneri and C. quinquedens from the Gulf of Mexico. Based on 16S rDNA and ITS data, genetic differences between C. quinquedens from southern New England and the Gulf of Mexico are large enough to conclude that these are different fishery stocks. Our results also indicate that the designation of morphological species within the commercially important genus Chaceon is not congruent with evolutionary history. The genetic similarity of C. affinis from the eastern Atlantic and C. quinquedens from the Gulf of Mexico suggests these trans-Atlantic taxa share a more recent common history than the two populations of "C. quinquedens" that we examined.

Genetic homogeneity and circum-Antarctic distribution of two benthic shrimp species of the Southern Ocean, Chorismus antarcticus and Nematocarcinus lanceopes

“…These results coincide with other examples of moderate to high genetic variability, which have been observed within various other deep-sea decapod crustaceans (e.g. Shank et al 1999;Weinberg et al 2003) or Wsh (Hoarau and Borsa 2000;Kojima et al 2001;Danielsdottir et al 2008). However, as in Chorismus antarcticus, there is also evidence for nonequilibrium as indicated from the neutrality test, the mismatch distribution and the obvious lack of diVerentiation in the mitochondrial 16S and nuclear 28S rDNA marker.…”

Circumantarctic distribution in Southern Ocean benthos? A genetic test using the genus Macroscapha (Crustacea, Ostracoda) as a model

“…Knowlton, 1993) and particularly in the deep-sea. This has been shown in several taxa such as amphipods (France andKocher, 1996), corals (Le Goff-Vitry et al, 2004), decapods (Weinberg et al, 2003) molluscs (Etter et al, 1999(Etter et al, , 2005 and vestimentiferans (Goffredi et al, 2003). In the case of 'Mh.…”

Population genetic structure in Sabatieria (Nematoda) reveals intermediary gene flow and admixture between distant cold seeps from the Mediterranean Sea

“…Genetic divergence in the marine environment may result from contemporary and historical processes related to the different oceanic basins [9], changes in seafloor topography [10], current regimes [11, 12], depth differences [13, 14], geographic distances [15] and oxygen levels [16]. For instance, genetic divergence in several benthic species is greater between populations at different depths in the same region than between populations of different regions at the same depth (e.g., [14, 17–19]).…”