Genetic differentiation of Common Tern (Sterna hirundo) colonies ; Upinių žuvėdrų (Sterna hirundo) kolonijų genetinė diferenciacija

For the analysis of genetic variability, samples of Common Tern were taken from five different colonies in Tauragė, Ignalina, Klaipėda, Birštonas and Zarasai districts. Eight polymorphic loci were identified, and their allele frequencies were estimated in the colonies as a result of electrophoretic analysis of enzyme systems (EST, MDH, ME) and a non-specific protein (NP) of liver and heart tissue homogenates, and blood serum. The mean number of alleles per locus in all colonies varied between 2.7 and 2.8. The mean heterozygosity (Ho) was 0.664-0.721. After summarising the allele frequencies in polymorphic loci of liver, heart and blood serum in all the colonies and the calculating coefficients of genetic distance and similarity (Nei 1972), the shortest genetic distance (0.038) was found between the Klaipėda and Tauragė colonies. Their coefficient of genetic similarity was 0.963. The genetic distance (0.112) was greatest between Zarasai and Tauragė colonies. Rather important genetic differences were observed between terns from the Birštonas and Klaipėda colonies (coefficient of genetic similarity was 0.896, while their genetic distance was 0.110). Cluster analysis of the data revealed the Zarasai and Ignalina colonies to form cluster and the Tauragė and Klaipėda colonies to form another one.