Population genetic structure of Mugil cephalus in the Mediterranean and Black Seas: a single mitochondrial clade and many nuclear barriers

Marine Ecology Progress Series

K. N. Shen¹  E. T. Koutrakis¹  H. Blel¹  J. D. Durand¹  B. Guinand¹ 

关键词: Microsatellites;    Mitochondrial DNA;    Gene flow;    Demography;    Mediterranean Sea ;    Mugilidae;    Bayesian clustering;    Bayesian skyline plot;   

DOI  :  10.3354/meps10080

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

ABSTRACT: The population structure and evolutionary history of Mugil cephalus were investigated across 18 sampling sites in the NE Atlantic Ocean, Mediterranean and Black Seas, using 2 classes of genetic markers: sequence polymorphism of an 857 bp fragment of mitochondrial (mtDNA) cytochrome b, and allele size variation at 7 nuclear loci. The level of nucleotide diversity recovered with the mtDNA marker was very low (~0.6% divergence), indicating the presence of a single clade over the entire area. Mismatch distribution, Bayesian skyline plots and associated statistics revealed a recent demographic crash followed by population expansion, but nuclear data indicated population constancy in the area covered in this study. While a single clade was detected, significant mtDNA genetic differentiation was, however, observed between the samples from the Black Sea and the samples from other (sub-) basins (Φ_ST = 0.17; p = 0.029). The nuclear loci also revealed significant genetic differentiation and isolation-by-distance in M. cephalus. Patterns of genetic structure were, however, significantly more pronounced with nuclear than with mtDNA markers; the former indicated the presence of 3 (Bayesian clustering) to 6 (Monmonnier’s method) populations. The highest levels of genetic heterogeneity at nuclear markers occurred at the well-known Almeria-Oran Front, but also in the Bosporus Strait. Thus, both sets of markers revealed the importance of this strait as a barrier to gene flow, probably during the Pleistocene. The results also revealed genetic heterogeneity in the eastern Mediterranean basin, and suggested that the population expanded from this sub-basin towards the Atlantic Ocean and Black Sea.

【 授权许可】

Unknown