Genetic variation in Phoca vitulina (the harbour seal) revealed by DNA fingerprinting and RAPDs

Genetic variation in two harbour seal (Phoca vitulina) populations from the Dutch Wadden Sea and Scotland was examined by RAPD analysis and DNA fingerprinting. For comparison a population of grey seals (Halichoerus grypus) was studied. The RAPD method revealed a very low number of polymorphic bands. The multilocus DNA fingerprinting technique showed very low levels of variation both within and between populations of the harbour seals. For one probe a significant difference in variation between populations was demonstrated. The estimated average heterozygosity, however, diverged more strongly between the two harbour seal populations because of more frequent occurrence of rare alleles in the Scottish population. Low levels of genetic variation seem to be characteristic for the subspecies Phoca vitulina vitulina, but not for all marine mammals in the North Sea, as the grey seal population showed significantly higher variation

The significance of genetic erosion in the process of extinction:I. Genetic differentiation in <i>Salvia pratensis</i> and <i>Scabiosa columbaria</i> in relation to population size

As part of a programme to determine the importance of the loss of genetic variation for the probability of population extinction, the amount of allozyme variation was determined in 14 populations of Salvia pratensis and in 12 populations of Scabiosa columbaria. Significant correlations were found between population size and the proportion of polymorphic loci (Salvia: r = 0.619; Scabiosa: r = 0.713) and between population size and mean observed number of alleles per locus (Salvia: r = 0.540; Scabiosa: r = 0.819). Genetic differentiation was substantially larger among small populations than among large populations: in Salvia G(ST) was 0.181 and 0.115, respectively, and in Scabiosa 0.236 and 0.101, respectively. The results are discussed in relation to genetic drift, inbreeding and restricted gene flow

Structure and amount of genetic variation at minisatellite loci within the subspecies complex of Phoca vitulina (the harbour seal).

The structure and amount of genetic variation within and between three subspecies of the harbour seal Phoca vitulina was assessed by multilocus DNA fingerprinting. Bandsharing similarity indicates that the subspecies Phoca vitulina richardsi (Alaska, East Pacific) is clearly separated from the other two subspecies, Phoca vitulina concolor (Sable Island, West Atlantic) and Phoca vitulina vitulina (North Sea, East Atlantic). The subspecies also differ significantly in the estimated amount of heterozygosity. Phoca vitulina richardsi has by far the highest amount of genetic variation, whereas P. vitulina vitulina has very low levels of genetic variation. Within the subspecies P. vitulina vitulina, especially the Wadden Sea population is depauperate of genetic variation. The findings are discussed in a historical, biogeographical and a conservation biological context