engleski

Disease epidemics with the possible impact on the genetic structure of contemporary Kvarner islanders – clues from mitochondrial DNA diversity

The Kvarner Island are situated in the Northern Adriatic Sea and have been populated since prehistory. Different historical events have shaped the population structure of those Island. Here we present a possible evidence of strong impact of certain disease epidemics on the genetic diversity and structure of the contemporary Kvarner islanders. Although the analysis of mitochondrial DNA haplogroups of autochthonous inhabitants from different islands showed relatively high level of haplogroup and haplotype diversity in the maternal gene pool, certain lineages become very abundant and represent a large portion of total haplogroups diversity. Generally decreased genetic diversity and gene flow in the Kvarner area can be explained by founder effect due to geographic isolation, as well as by strong bottleneck effects in particular periods of islands’ history. The strongest founder effect is recorded for the islands of Rab and Cres where one single haplotype accounts for more than 20 % of the population. For instance, every fourth contemporary Rab Islander has one particular haplotype of U4d2 haplogroup, which is so far the most frequent finding of this haplogroup ever reported in any population. One possible explanation of such deviation from average European frequency could be due to several epidemics of plague in 15th and 16th century when a vast majority of population died, in some cases almost 90 % of some settlements were devastated. A high deviation from standard frequency of haplogroups in certain Krk island settlements could be also connected to the epidemics of cholera during the 19th century.

mitochondrial DNA; isolated populations; Kvarner islands; genetic drift; plaque; cholera; population structure

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