Amine-citrate buffer systems for pH control in starch gel electrophoresis gave good resolution of some dehydrogenase isozymes. The pK's of three new amine buffers, N-(3-aminopropyl)-morpholine, pK2 25 C, 6.12; N-(3-aminopropyl)-diethanolamine, pK2 25 C, 6.90; and 1,3-bis(dimethylamino)-2-propanol, pK2 25 C, 7.55, were determined at 5 C intervals in the range 10–40 C. These compounds, together with N, N-bis(2-hydroxyethyl)iminotris(hydroxymethyl)methane (bis-Tris) and tris-(hydroxymethyl)-methylamine(Tris), provide a series of amine buffers with pK's at 0.5 unit intervals in the pH range 6.1–8.1.

The North American beluga whale Delphinapterus leucas population has been divided into a number of putative geographical stocks based upon migration routes and areas of summer concentration. Nucleotide sequences of the mitochondrial DNA (mtDNA) control region were used to assess whether these geographical stocks are genetically distinct. Beluga whale samples from 25 sites were collected primarily from aboriginal subsistence hunts across North America from 1984 to 1994. Thirty-nine mtDNA haplotypes were identified in 628 beluga samples. No differences were found in the distribution of haplotypes between male and female beluga whales at any sampling site. These haplotypes segregated into two distinct assemblages in both a haplotype network and a neighbour-joining tree. The haplotype assemblages and a geographically disjunct distribution that suggests postglacial recolonization of the North American Arctic from two different refugia. An analysis of molecular variance based on haplotype relationships and frequency indicated genetic heterogeneity among beluga whale summering groups (P < or = 0.001). Sequence divergence estimates between sampling sites also indicated geographical differentiation, particularly between samples taken at east Hudson Bay or St Lawrence River and the western or central Arctic. The results of this study show a high degree of philopatry to specific summering areas by this highly mobile animal.

Fifteen microsatellites were isolated from a beluga whale Delphinapterus leucas, genomic library. The microsatellites were amplified in 100 beluga obtained from two widely separated locations. An average of 8.6 alleles per locus were detected and the average heterozygosity was 0.65 with a range of 0.27-0.86. All microsatellites were polymorphic and 13 of the genotype distributions observed were in Hardy-Weinberg equilibrium. It was possible with these microsatellites to assign correctly individual whales to their stock-of-origin 98% of the time. Microsatellites were amplified in 15 other cetaceans with these beluga-derived primers.

Beluga whales (Delphinapterus leucas) in North American waters migrate seasonally between wintering areas in broken pack ice and summering locations in estuaries and other open water areas in the Arctic and sub-Arctic. Results from our previous investigation of beluga whale mitochondrial DNA (mtDNA) revealed genetic heterogeneity among beluga from different summering locations that was interpreted as representing a high degree of summering site philopatry. However, mtDNA is maternally inherited and does not reflect mating that may occur among beluga from different summering locations in wintering areas or during annual migrations. To test the possibility that breeding occurs among beluga from different summering locations, genetic variability at five nuclear DNA (nDNA) microsatellite loci was examined in the same animals tested in the mtDNA study. Beluga samples (n = 640) were collected between 1984 and 1994 from 24 sites across North America, mostly during the summer. Whales from the various sites were categorized into eight summering locations as identified by mtDNA analysis, as well as four hypothesized wintering areas: Bering Sea, Hudson Strait (Hudson Strait, Labrador Sea, southwest Davis Strait), Baffin Bay (North Water, east Davis Strait), and St Lawrence River. Microsatellite allele frequencies indicated genetic homogeneity among animals from summering sites believed to winter together but differentiation among whales from some of the wintering areas. In particular, beluga from western North America (Bering Sea) were clearly distinguished from beluga from eastern North America (Hudson Strait, Baffin Bay, and St Lawrence River). Based upon the combined data set, the population of North American beluga whales was divided into two evolutionarily significant units. However, the population may be further subdivided into management units to reflect distinct groups of beluga at summering locations.

Fifteen microsatellites were isolated from a beluga whale Delphinapterus leucas, genomic library. The microsatellites were amplified in 100 beluga obtained from two widely separated locations. An average of 8.6 alleles per locus were detected and the average heterozygosity was 0.65 with a range of 0.27-0.86. All microsatellites were polymorphic and 13 of the genotype distributions observed were in Hardy-Weinberg equilibrium. It was possible with these microsatellites to assign correctly individual whales to their stock-of-origin 98% of the time. Microsatellites were amplified in 15 other cetaceans with these beluga-derived primers.