Genetic variation and population structure of the carpet shell clam Ruditapes decussatus along the Tunisian coast inferred from mtDNA and ITS1 sequence analysis

Biologia (Impact Factor: 0.51). 65(4):688-696. DOI: 10.2478/s11756-010-0069-8

ABSTRACT Surveys of allozyme polymorphisms in the carpet shell clam Ruditapes decussatus have revealed sharp genetic differentiation of populations. Analysis of population structure in this species has now been
extended to include nuclear and mitochondrial genes. A partial sequence of a mitochondrial COI gene and of the internal transcribed
spacer region (ITS-1) were used to study haplotype distribution, the pattern of gene flow, and population genetic structure
of R. decussatus. The samples were collected from twelve populations from the eastern and western Mediterranean coasts of Tunisia, one from
Concarneau and one from Thau. A total of twenty and twenty-one haplotypes were detected in the examined COI and ITS1 regions
respectively. The study revealed higher levels of genetic diversity for ITS1 compared to COI. The analysis of haplotype frequency
distribution and molecular variation indicated that the majority of the genetic variation was distributed within populations
(93% and 86% for COI and ITS1 respectively). No significant differentiation was found among eastern and western groups on
either side of the Siculo-Tunisian strait. However, distinct and significant clinal changes in haplotypes frequencies between
eastern and western samples were found at the most frequent COI haplotype and at three out of five major ITS1 haplotypes.
These results suggest the relative importance of historical processes and contemporary hydrodynamic features on the observed
patterns of genetic structure.

Key wordsRuditapes decussates-COI-ITS1-Tunisia

  • [Show abstract] [Hide abstract]
    ABSTRACT: The population genetic structure of the Peruvian scallop Argopecten purpuratus from three different wild populations along the Peruvian coast was analyzed using nine microsatellite loci and a partial region (530bp) of the mitochondrial 16S rRNA gene. A total of 19 polymorphic sites in the 16S rRNA gene defined 18 unique haplotypes. High genetic diversity was presented in all populations. Statistical analysis of mitochondrial DNA revealed no significant genetic structure (ΦST=0.00511, P=0.32149) among the three localities. However, microsatellite analysis showed low (2.86%) but highly significant (P=0.0001) genetic differentiation among populations, most of the variation was found in Independencia Bay population, which is located in the Peruvian National Reserve of Paracas. Neutrality tests based on mitochondrial haplotypes were performed to assess signatures of recent historical demographic events. Overall results from Tajima's D and Fu's FS tests indicated significant deviations from neutrality. To our knowledge, this study constitutes the first investigation based on mitochondrial and microsatellite markers on the genetic structure of A. purpuratus.
    Marine Genomics 03/2013; 9:1-8. · 1.34 Impact Factor