engleski

Croatian coast and islands - A new contact zone between eastern and western lineages of garden snail, Cornu aspersum (Gastropoda:Helicidae) – Evidences from mitohondrial DNA analyses.

Several morphological and molecular studies confirmed two major haplogroups (east and west) of brown garden snail, Cornu aspersum O.F. Müller, 1774 (= Helix aspersa O.F. Müller, 1774). Investigations, however, were confirmed mainly to the West Mediterranean region. The present study attempted to elucidate the phylogeography C. aspersum along the Croatian (East-Adriatic) coast and islands. The results show that 55 C. aspersum individuals collected at 15 sampling sites grouped into 12 haplotypes for 16S RNA and split into two major lineages corresponding to east and west type. The east type was more frequent as compared to the west type and was found along entire of this region. It is characterized by higher 16S haplotype and nucleotide diversity and represented by several sub-groups. The west type of C. aspersum, represented with only two 16S haplotypes, was restricted to the central and south part of Adriatic coast and its islands, where these two haplotype lineages form a new, as yet unidentified, contact zone. The same results were additionally obtained by analysis of cytochrome b (cytb) and for the first time by cytochrome oxidase I (COI) haplotype distribution. Our results thus indicate that: i) the putative ancestral eastern haplotype lineage, which disappeared in most Mediterranean countries persisted in East- Adriatic area probably through several climatic cycles and accumulated genetic differences ii) two or, more likely, several independent postglaciation colonization routes crossed at this contact zone thus bringing two distinct C. aspersum haplogroups together.

Cornu aspersum; 16S RNA; COI; cytb; Eastern and western haplotypes; New secondary contact zone in Croatia

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