Genetic variation of the St. Lawrence beluga whale population assessed by DNA fingerprinting.

Recent surveys suggest that the endangered St. Lawrence beluga (Delphinapterus leucas) population is not recovering significantly despite 20 years of protection. Dead individuals that have been autopsied show high levels of tumours and infections. This situation could be a result of pollution, loss of genetic variation, inbreeding depression or a combination of these factors. Analyses of DNA fingerprints from St. Lawrence belugas with three minisatellite probes (Jeffreys 33.6, 33.15 and M13) indicate a reduced level of genetic variation compared to Beaufort Sea animals. The average band-sharing between individuals of the St. Lawrence beluga population for the three probes (0.534, 0.573 and 0.478, respectively) was significantly higher than that of the Beaufort Sea beluga population (0.343, 0.424, 0.314, respectively). Higher levels of mean allele frequency in the St. Lawrence belugas (0.33 vs. 0.21) suggest that this population is composed of individuals which are related. Inbreeding depression could therefore be a factor in the lack of recovery of the St. Lawrence beluga population.