engleski

Ambiguous evidence of a recent bottleneck in the Adriatic bottlenose dolphins (Tursiops truncatus)

The bottlenose dolphin (Tursiops truncatus) is an endangered and legally protected species in Croatia, whose demographic history is poorly known. It is the only resident marine mammal species in Croatian part of the Adriatic Sea, with number estimated at around 250 individuals. There are indications that there has been intensive eradication operations in the mid 20th century that might have caused reductions in the effective population size and might have resulted in a loss of genetic variation. Therefore, we aimed to investigate a possibility of recent population size contraction and to compare the level of genetic diversity in the bottlenose dolphin population from the Croatian part of the Adriatic Sea with other bottlenose dolphin populations. Thirty samples were genotyped at 12 dinucleotide microsatellite loci. Bottleneck analysis gave ambiguous evidence for a recent population decline in the investigated bottlenose dolphin population. M ratio test, with two sets of parameter values, suggested a recent bottleneck ; whereas analysis by Bottleneck program under two mutation models (TPM and SMM) showed no evidence for a genetic bottleneck. In addition, there was no evidence for a significant deviation from the normal L-shaped distribution of allele frequencies as expected for a stable population under mutation-drift equilibrium. Furthermore, both allelic richness (6.956) and expected heterozygosty (0.676) of the Adriatic population are above mean of all compared populations (5.993 and 0.658, respectively), confirming relatively high level of genetic diversity in the investigated Adriatic population. Due to ambiguous results, further research is needed to elucidate demographic history of this bottlenose dolphin population.

bootlenose dolphin

nije evidentirano