Population structure of North American beluga whales (
            Delphinapterus leucas
            ) based on nuclear DNA microsatellite variation and contrasted with the population structure revealed by mitochondrial DNA variation

Beluga whales (Delphinapterus leucas) are migratory over much of their range, congregating in small groups around shallow river estuaries in summer and overwintering in areas of broken pack ice. To investigate the potential genetic structuring within North American beluga, we analyzed variation in mitochondrial DNA (mtDNA). Using 10 restriction enzymes, eight haplotypes were identified among 95 beluga from 12 sampling locations. The haplotypes formed two lineages, one occurring primarily in whales from the St. Lawrence estuary and eastern Hudson Bay and the other primarily in beluga sampled in the waters of western Hudson Bay, southern Baffin Island, western Greenland, the Canadian High Arctic, and the eastern Beaufort Sea. The genetic difference between these lineages and the high-level genetic structure among the sample locations, [Formula: see text] (p ≤ 0.0001), indicate that these lineages may represent the original Pacific and Atlantic "refugial" stocks that colonized the Arctic after deglaciation. Further, the present segregation of these lineages between populations summering in eastern and western Hudson Bay (p ≤ 0.005) is consistent with the hypothesis that the mitochondria of the beluga summering in western Hudson Bay are descended from those of a Pacific "refugial" stock and those of beluga summering in eastern Hudson Bay are descended from those of an Atlantic "refugial" stock. The clear differentiation of beluga from different summering locations provides evidence for strong maternally directed philopatry to the summering locations.

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Mitochondrial and nuclear DNA variation, genotype fingerprinting and genetic relationships in lentil (Lens culinaris Medik.)

Canadian Journal of Plant Science ◽

10.4141/p96-133 ◽

1997 ◽

Vol 77 (4) ◽

pp. 515-521 ◽

Cited By ~ 1

Author(s):

Om P. Rajora ◽

John D. Mahon

Keyword(s):

Mitochondrial Dna ◽

Restriction Fragment ◽

Lens Culinaris ◽

Nuclear Dna ◽

Genetic Relationships ◽

Restriction Enzymes ◽

Dna Variation ◽

Apocytochrome B ◽

Nuclear Dna Variation ◽

Mean Similarity

Mitochondrial DNA (mtDNA) and nuclear DNA (nuDNA) variations were examined in six cultivars of Lens culinaris ssp. culinaris and two (mtDNA) or one (nuDNA) accession(s) of L. culinaris ssp. orientalis. Total leaf DNA was digested with up to 15 restriction endonucleases, separated by agarose gel electrophoresis and trasferred to nylon membranes. To examine mtDNA variation, blots were probed with mtDNA coding for cytochrome c oxidase I (coxI) and ATPase 6 (atp6) of both wheat and maize as well as apocytochrome b (cob) and Orf25 (orf25) of wheat. Sixteen combinations of mtDNA probes and restriction enzymes revealed 34 fragments that discriminated between at least two lentil accessions. For nuDNA analysis, probes from cDNA and genomic DNA clones of lentil were used to probe the same blots, and identified 46 diagnostic fragments from 19 probe/enzyme combinations. Each lentil accession could be unequivocably distinguished from all others on the basis of both mitochondrial and nuclear DNA fragment patterns. The mitochondrial restriction fragment similarities ranged from 0.944 to 0.989, with a mean of 0.970 but nuclear restriction fragment similarities varied from 0.582 to 0.987, with a mean of 0.743. The apparent genetic relationships among accessions differed according to the source of DNA examined, although the commercial varieties Laird, Brewer and Redchief showed similarly high levels of mean similarity with both nuclear (0.982) and mitochondrial DNA (0.983). Key words: Lens culinaris Medik., genetic variation, mitochondrial, nuclear, DNA, lentil

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