engleski

Nuclear marker Me 15/16 analyses of Mytilus galloprovincialis populations along the eastern Adriatic coast

Mussels Mytilus spp. belong to a group of key species in coastal marine ecosystems. This work demonstrates the dominant presence of Mediterranean mussel M. galloprovincialis along eastern Adriatic coast. Morphometric characteristics of sampled mussels were inside normal values for M. galloprovincials, with a height/length ratio of 55.89 ± 5.08 % and a width/length ratio of 38.76 ± 3.42 %. For the first time different alleles of the Me 15/16 locus are reported in populations of Croatian Adriatic Sea. However, two specimens among the 110 analysed showed a heterozygote genotype: one with an E (M. edulis) allele and one with a T (M. trossulus) allele, all others were identified as homozygotes for the G (M. galloprovincialis) allele. By sequencing PCR products we proved that the 126 bp, 168 bp and 180 bp bands correspond to the G, T and E alleles previously reported. The presence of the E allele at low frequency in M. galloprovincialis mussels can simply be explained by introgression, as M. edulis and M. galloprovincialis are known to hybridise and exchange genes. Faraway from M. trossulus distribution area, the presence of the T allele, as well as E allele, is very surprising. According to the current distribution of these three species, T allele would first need to introgress into M. edulis before having the opportunity to introgress into M. galloprovincialis. The Me 15/16 locus itself does not appear to be completely diagnostic between the three species and should be combined with other nuclear markers.

M. galloprovincialis; Me 15/16; heterozygote; morphometric variation; Adriatic Sea

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