We report that a single nucleotide replacement in the melanocortin 1 receptor gene [1] (mc1r) is responsible for the white coat color of the "Kermode" bear [2], a color phase of the black bear (Ursus americanus Pallus) found in the rainforests along the north coast of British Columbia. In a sample of 220 bears, of which 22 were white, there was complete association of a recessive Tyr-to-Cys replacement at codon 298 with the white phase. This variant has not been yet been reported in other mammals, and it also is the lightest-colored variant yet found at mc1r. Also, we found that heterozygotes, which act as a hidden reservoir for the allele among black bears, were infrequent outside of the three islands where Kermodes are common and that, within these three islands, heterozygotes were less frequent than expected under random mating. Immigration of black bears into Kermode populations can depress the occurrence of the white phase, and management practices should be designed to avoid facilitating higher immigration rates.

The Canadian side of the Pacific Northwest was almost entirely covered by ice during the last glacial maximum, which has induced vicariance and genetic population structure for several plant and animal taxa. Lodgepole pine (Pinus contorta Dougl. ex. Loud.) has a wide latitudinal and longitudinal distribution in the Pacific Northwest. Our main objective was to identify relictual signatures of glacial vicariance in the population structure of the species and search for evidence of distinct glacial refugia in the Pacific Northwest. A maternally inherited mitochondrial DNA minisatellite-like marker was used to decipher haplotype diversity in 91 populations of lodgepole pine located across the natural range. Overall population differentiation was sizeable (G(ST) = 0.365 and R(ST) = 0.568). Four relatively homogeneous groups of populations, possibly representative of as many genetically distinct glacial populations, were identified for the two main subspecies, ssp. latifolia and ssp. contorta. For ssp. contorta, one glacial lineage is suggested to have been located at high latitudes and possibly off the coast of mainland British Columbia (BC), while the other is considered to have been located south of the ice sheet along the Pacific coast. For ssp. latifolia, two genetically distinct glacial populations probably occurred south of the ice sheet: in the area bounded by the Cascades and Rocky Mountains ranges, and on the eastern side of the Rockies. A possible fifth refugium located in the Yukon may have also been present for ssp. latifolia. Zones of contact between these ancestral lineages were also apparent in interior and northern BC. These results indicate the role of the Queen Charlotte Islands and the Alexander Archipelago as a refugial zone for some Pacific Northwest species and the vicariant role played by the Cascades and the American Rocky Mountains during glaciation.

The cloning of white spruce (Picea glauca) mitochondrial DNA homologous to the cytochrome oxidase II and ATPaseα genes of maize is described. These probes were used to define restriction fragment length polymorphisms which distinguish the white, Engelmann (P. engelmannii) and Sitka spruce (P. sitchensis) populations that occur in British Columbia. Analysis of progeny from crosses between the species revealed that mitochondrial DNA was maternally inherited in all cases (32 progeny from five independent crosses). The inheritance of chloroplast DNA was determined using a probe described previously; in this case, all progeny exhibited paternal inheritance (27 progeny from four crosses). Mitochondrial and chloroplast probes were used to test trees from zones of introgression between coastal (Sitka) and interior spruces (white and Engelmann). In most cases mitochondria and chloroplasts within individuals were contributed by different species. The data shows that there is a significant Sitka spruce component in trees east of the coastal watershed in British Columbia.

We employed a novel set of six highly polymophic chloroplastic simple sequence repeat (cpSSR) loci to investigate the phylogeography of lodgepole pine ( Pinus contorta Dougl. Ex. Loud.), and to examine aspects of the evolutionary process operating on these repetitive DNA sequences. Chloroplast haplotypes of 500 trees, sampled throughout the range of lodgepole pine, were determined. We found a marked association of genetic distance with physical distance within the scale of 0 to 1,000 km, but no association beyond that range. Likewise, geographic clustering was observed only among recent clades in a dendrogram. These phylogeographic patterns are consistant with a rapid rangewide expansion ("big-bang") followed by recent, local population differentiation ("galaxy formation"). In support of this expansion, coalescent simulations of the genealogical process gave a long-term effective population size in the low thousands, and a time to common ancestry of about 1,500 generations (12,000 years), consistent with a post-Pleistocene population expansion as documented by previous pollen-sediment analyses. Two lines of evidence (mapping mutational events onto a phylogeny, and evaluation of observed versus expected gene diversity) suggest that five of the cpSSR loci evolve primarily by a stepwise model of evolution of single repeat changes (but with a small proportion of changes involving two or more repeats), and the coalescent simulations point to a mutation rate of about 10(-3).

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Restriction fragment length polymorphisms of the nuclear ribosomal RNA genes were used to define species-specific patterns for interior spruce (a complex of white spruce, Piceaglauca (Moench) Voss, and Engelmann spruce, Piceaengelmannii Parry) and Sitka spruce (Piceasitchensis (Bong.) Carr.) populations in British Columbia. These patterns are highly conserved among seed lots and individual trees of each species from diverse geographic origins. Both the ribosomal RNA gene probe and species-specific probes for the chloroplast and mitochondrion, described previously, were used to analyze 164 dominant trees from 19 locations in a zone of presumed Sitka–interior spruce introgression in northwestern British Columbia. Hybrid fraction was estimated from an index based on the relative abundance of polymorphic ribosomal RNA hybridizing bands for each tree and was in good agreement with the proportion of trees exhibiting either interior or Sitka spruce specific chloroplast bands. The results demonstrate that complex hybrids occur frequently in this zone, indicative of true introgression. Furthermore, the trend of variation in species mix is consistent with the topographical trends. It is anticipated that the results of this survey will be useful in defining seed transfer guidelines for reforestation of this region.

A seed storage protein cDNA was characterized from a library of interior spruce (Picea glauca/engelmanii complex) cotyledonary stage somatic embryos. The deduced amino acid sequence predicts a 448 amino acid (50 kDa) polypeptide with 28-38% identity with angiosperm vicilin-like 7S globulins. XXC/G codon usage is low (47%) relative to monocot angiosperms while pairwise comparisons show that spruce, monocot, and dicot vicilins are approximately equal in amino acid divergence. Although small by comparison, the spruce vicilin contains an N terminal hydrophilic region characteristic of angiosperm 'large' vicilins. Genomic Southern blotting predicts that the cDNA is encoded by a gene family.