Genetic Structure of Czech and Slovak Populations of the Eurasian Otter (Lutra lutra): DNA Typing of Spraints and Microsatellite Variability

In 2003, a project aiming to assess Eurasian otter population size and structure in 2 different habitats in the Czech and Slovak Republics using genetic typing of spraints was started. Initial testing showed that analysis success rate was significantly influenced by (1) type of sample (anal jellies better than spraints); and (2) weather (negative impact of increasing temperature). Therefore, samples were collected in cold months only, and jelly samples and spraints with jelly or mucus were taken in preference. Samples need to be very fresh (≤18 hrs) and should be sub-sampled into several tubes to obtain sufficient amount of DNA. In general, around 70% of all samples were successfully genotyped. To date, 11 different genotypes, corresponding to 11 otter individuals (5 females and 6 males), have been identified in the mountainous area of the Slovensky Raj National Park, Slovakia. Tissue samples from carcasses from the Czech (n = 57) and Slovak (n = 22) Republics, and genotypes identified from spraints (n = 11), were used to study genetic diversity. Most of the Czech population formed part of a relatively strong but isolated Czech-Austrian-German population; while the Slovak population formed part of the Central and Eastern European otter distribution range. A relatively narrow (50-80 km) region with no otter presence separated the populations; however, the Czech population has very recently reconnected with the otter population in Eastern Europe through Poland. Values of allelic richness (Rs) and observed heterozygosity (Ho) were similar for both populations (Rs: Czech = 4.21, Slovak = 4.33; Ho: Czech = 0.643, Slovak = 0.565). The overall Fst (fixation index) value was significant (Fst = 0.128; P < 0.001), indicating the existence of a gene flow barrier between populations and confirming their moderate genetic differentiation. Both Czech and Slovak populations, however, exhibited a Hardy-Weinberg equilibrium (Fis = N.S.), i.e. there was no evidence for inbreeding in these populations.