scholarly journals Transferrin variation and evolution of Canadian barren-ground caribou

Rangifer ◽  
1990 ◽  
Vol 10 (3) ◽  
pp. 385 ◽  
Author(s):  
Knut H. Røed ◽  
D. C. Thomas
Keyword(s):  
Genetic Variation ◽  
Allele Frequency ◽  
Gel Electrophoresis ◽  
Rangifer Tarandus ◽  
High Arctic ◽  
Ancestral Population ◽  
Allele Frequency Distribution ◽  
Frequency Pattern ◽  
Barren Ground ◽  
Svalbard Reindeer

Blood samples were obtained from 95 barren-ground caribou (Rangifer tarandus groenlandicus) of the Beverly herd in Northwest Territories, Canada. Polyacrylamid gel electrophoresis was used to score for genetic variation in the locus coding for transferrin. The pattern of allele frequency distribution are compared with previously reported values of Eurasian tundra reindeer (R.t. tarandus), Alaska caribou (R.t. granti), Peary caribou (R.t. pearyi), and Svalbard reindeer (R.t. platyrhynchus). In the Beverly herd a total of 21 different transferrin alleles were detected. The amount of genetic variation was higher in the Canadian barren-ground caribou than what has been detected in other subspecies of reindeer/caribou. Highly gene-tical differences in the allele frequencies were detected between the Canadian barren-ground caribou and the other subspecies. The genetic identity analyses indicates approximately the same amount of genetic differentiation when the Canadian barren-ground caribou are compared with Alaska caribou as with the Peary caribou. The allele frequency pattern could be explained by a possible origin of the Canadian barren-ground caribou from an ancestral population which was genetical influenced by animals surviving the We-ichselian glaciation in refugia both in high Arctic, in Beringia, and south of the ice sheet.

scholarly journals Transferrin variation and evolution of Alaskan reindeer and caribou, Rangifer tarandus L.

Rangifer ◽  
1986 ◽  
Vol 6 (2) ◽  
pp. 247 ◽  
Author(s):  
Knut H. Røed ◽  
Ken R. Whitten
Keyword(s):  
Allele Frequency ◽  
Frequency Distribution ◽  
Gel Electrophoresis ◽  
Rangifer Tarandus ◽  
Polyacrylamide Gel Electrophoresis ◽  
Polyacrylamide Gel ◽  
Allele Frequency Distribution ◽  
Common Allele ◽  
Frequency Distributions ◽  
Svalbard Reindeer

Polyacrylamide gel electrophoresis was used to analyse transferrin variation in wild caribou (Rangifer tarandus granti) and domestic reindeer (R.t. tarandus) from Alaska. Eighteen alleles were detected in caribou and ten alleles were detected in reindeer. The most common allele was Tf 1 with a frequency of 0.304 and 0.408 in caribou and reindeer, respectively. The allele frequency distributions were significantly different in reindeer and caribou. This finding, together with the absence in reindeer of nine alleles present in caribou, suggests that little genetic exchange has taken place between caribou and reindeer in Alaska. The allele frequency distribution in Alaska caribou and reindeer are compared with those for other populations of caribou and reindeer. This comparison indicates that Alaskan caribou as well as Eurasian reindeer have evolved from a common ancesteral population different from the ancesteral population of Peary cairbou (R.t. pearyi) and Svalbard reindeer (R.t. platyrhynchus).

Transferrin variation in caribou (Rangifer tarandus L.) on the Canadian Arctic islands

1986 ◽  
Vol 64 (1) ◽  
pp. 94-98 ◽  
Author(s):  
K. H. Røed ◽  
H. Staaland ◽  
E. Broughton ◽  
D. C. Thomas
Keyword(s):  
Genetic Distance ◽  
Gel Electrophoresis ◽  
Rangifer Tarandus ◽  
Polyacrylamide Gel Electrophoresis ◽  
Canadian Arctic ◽  
High Arctic ◽  
Polyacrylamide Gel ◽  
Common Allele ◽  
Island Populations ◽  
Svalbard Reindeer

Polyacrylamide gel electrophoresis was used to analyse transferrin variation in caribou from the Canadian Arctic islands. Sixteen alleles were detected in Peary caribou (Rangifer tarandus pearyi). The most common allele was TfG2, which increased in frequency from 0.167 at the Boothia Peninsula to 0.236 in the Peel population and 0.340 in the Parry population. The presence of this allele, which is the most common allele in Svalbard reindeer (R. t. platyrhynchus) and not detected in Norwegian reindeer (R. t. tarandus), suggests a common origin for the Peary caribou and the Svalbard reindeer. The large genetic distance in the transferrin locus between continental and island populations suggests the isolation of a High Arctic population in a northern refugium during the Wisconsin glaciation.

Comparison of the genetic variation in Svalbard and Norwegian reindeer

1985 ◽  
Vol 63 (9) ◽  
pp. 2038-2042 ◽  
Author(s):  
K. H. Røed
Keyword(s):  
Genetic Variation ◽  
Rangifer Tarandus ◽  
Polyacrylamide Gel Electrophoresis ◽  
Divergence Time ◽  
Recent Time ◽  
Evolutionary Divergence ◽  
Average Heterozygosity ◽  
Polymorphic Loci ◽  
Svalbard Reindeer ◽  
Long Time

Polyacrylamide gel electrophoresis was used to score for genetic variation in 35 loci in Svalbard reindeer, Rangifer tarandus platyrhynchus, and in reindeer, Rangifer tarandus tarandus, from two localities in northern Norway. In R. t. platyrhynchus the proportion of polymorphic loci was 0.114 and the average heterozygosite was 0.030. In R. t. tarandus the proportion of polymorphic loci was 0.171–0.286 and the average heterozygosity was 0.043–0.045. Excluding the variability in the locus coding for transferrin from calculations reduced the average heterozygosity to 0.020 in R. t. platyrhynchus and to 0.021–0.025 in R. t. tarandus, suggesting that the amount of genetic variation in R. t. platyrhynchus is not very different from that in R. t. tarandus. Unique alleles in the loci coding for transferrin and acid phosphatase for the two subspecies indicate that there has been no interbreeding in recent time. The genetic distance between the two subspecies is within the same range as between subspecies of other organisms. Evolutionary divergence time based on the protein data indicates that either the divergence between these subspecies was initiated a very long time ago or R. t. platyrhynchus originates from other subspecies of reindeer.

scholarly journals Genetic diversity, structure and gene flow of migratory barren-ground caribou (Rangifer tarandus groenlandicus) in Canada

Rangifer ◽  
2016 ◽  
Vol 36 (1) ◽  
pp. 1 ◽  
Author(s):  
Keri McFarlane ◽  
Anne Gunn ◽  
Mitch Campbell ◽  
Mathieu Dumond ◽  
Jan Adamczewski ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Gene Flow ◽  
Rangifer Tarandus ◽  
Continuous Distribution ◽  
Effective Population ◽  
Genetic Population ◽  
Barren Ground ◽  
Cyclic Changes ◽  
Rangifer Tarandus Groenlandicus

Migratory barren-ground caribou (Rangifer tarandus groenlandicus) provide an opportunity to examine the genetic population structure of a migratory large mammal whose movements and distribution, in some instances, have not been heavily influenced by human activities that result in habitat loss or fragmentation. These caribou have likely reached large effective population sizes since their rapid radiation during the early Holocene despite cyclic changes in abundance. Migratory barren-ground caribou are managed as discrete subpopulations. We investigated genetic variation among those subpopulations to determine the patterns of genetic diversity within and among them, and the implications for long-term persistence of caribou. We identified three distinct genetic clusters across the Canadian arctic tundra: the first cluster consisted of all fully-continental migratory barren-ground subpopulations; the second cluster was the Dolphin and Union caribou; and the third cluster was caribou from Southampton Island. The Southampton Island caribou are especially genetically distinct from the other barren-ground type caribou. Gene flow among subpopulations varied across the range. Occasional gene flow across the sea-ice is likely the reason for high levels of genetic variation in the Dolphin and Union subpopulation, which experienced very low numbers in the past. These results suggest that for most migratory caribou subpopulations, connectivity among subpopulations plays an important role in maintaining natural genetic diversity. Our analyses provide insight into the levels of microsatellite genetic diversity and patterns of gene flow that may be common to large subpopulations that historically had a continuous distribution across a large continental range. These data can also be used as a benchmark to compare the effects of habitat fragmentation and bottlenecks on other large caribou populations.

Partial seasonal migration in high-arctic Svalbard reindeer (Rangifer tarandus platyrhynchus)

2010 ◽  
Vol 88 (12) ◽  
pp. 1202-1209 ◽  
Author(s):  
B. B. Hansen ◽  
R. Aanes ◽  
B.-E. Sæther
Keyword(s):  
Rangifer Tarandus ◽  
High Arctic ◽  
Population Trend ◽  
Seasonal Migration ◽  
Migration Route ◽  
Free System ◽  
Svalbard Reindeer ◽  
The Poor ◽  
Trade Offs ◽  
The Rich

We examined seasonal range use and calving success in wild Svalbard reindeer ( Rangifer tarandus platyrhynchus Vrolik, 1829) on two contrasting ranges separated by risky barriers (open sea, thin sea ice, and glaciers). One (“poor”) range had a depleted lichen resource and negative reindeer population trend, whereas the neighbouring (“rich”) range was recently occupied with initially high lichen abundance and positive population trend. Winter foraging conditions limit survival and reproduction in this predator-free system and lichens are the preferred winter food by reindeer. Accordingly, marked female reindeer that switched between the ranges (“migrants”) spent most winters on the lichen-rich range, yet most summers on the poor range (possibly owing to fidelity to calving area). While facing high mortality risk along the migration route, migrants spending the winter on the rich range and subsequent summer on the poor range had improved calving success compared with residents on the poor range. The partial seasonal migration pattern diminished as lichens were reduced and reindeer carrying capacity reached on the rich range. Besides this apparent density-dependence in migratory behaviour, spatial strategy seems shaped by past experience and trade-offs between current survival (safe habitat) and future reproduction (food-rich habitat).

scholarly journals A model of compound heterozygous, loss-of-function alleles is broadly consistent with observations from complex-disease GWAS datasets

2016 ◽  
Author(s):  
Jaleal S. Sanjak ◽  
Anthony D. Long ◽  
Kevin R. Thornton
Keyword(s):  
Genetic Variation ◽  
Allele Frequency ◽  
Population Genetic ◽  
Complex Disease ◽  
Genetic Model ◽  
Disease Risk ◽  
Association Studies ◽  
Allele Frequency Distribution ◽  
Genome Wide Association Studies ◽  
Heritability Estimation

AbstractThe genetic component of complex disease risk in humans remains largely unexplained. A corollary is that the allelic spectrum of genetic variants contributing to complex disease risk is unknown. Theoretical models that relate population genetic processes to the maintenance of genetic variation for quantitative traits may suggest profitable avenues for future experimental design. Here we use forward simulation to model a genomic region evolving under a balance between recurrent deleterious mutation and Gaussian stabilizing selection. We consider multiple genetic and demographic models, and several different methods for identifying genomic regions harboring variants associated with complex disease risk. We demonstrate that the model of gene action, relating genotype to phenotype, has a qualitative effect on several relevant aspects of the population genetic architecture of a complex trait. In particular, the genetic model impacts genetic variance component partitioning across the allele frequency spectrum and the power of statistical tests. Models with partial recessivity closely match the minor allele frequency distribution of significant hits from empirical genome-wide association studies without requiring homozygous effect-sizes to be small. We highlight a particular gene-based model of incomplete recessivity that is appealing from first principles. Under that model, deleterious mutations in a genomic region partially fail to complement one another. This model of gene-based recessivity predicts the empirically observed inconsistency between twin and SNP based estimated of dominance heritability. Furthermore, this model predicts considerable levels of unexplained variance associated with intralocus epistasis. Our results suggest a need for improved statistical tools for region based genetic association and heritability estimation.Author SummaryGene action determines how mutations affect phenotype. When placed in an evolutionary context, the details of the genotype-to-phenotype model can impact the maintenance of genetic variation for complex traits. Likewise, non-equilibrium demographic history may affect patterns of genetic variation. Here, we explore the impact of genetic model and population growth on distribution of genetic variance across the allele frequency spectrum underlying risk for a complex disease. Using forward-in-time population genetic simulations, we show that the genetic model has important impacts on the composition of variation for complex disease risk in a population. We explicitly simulate genome-wide association studies (GWAS) and perform heritability estimation on population samples. A particular model of gene-based partial recessivity, based on allelic non-complementation, aligns well with empirical results. This model is congruent with the dominance variance estimates from both SNPs and twins, and the minor allele frequency distribution of GWAS hits.

Feeding-crater selection by high-arctic reindeer facing ice-blocked pastures

2010 ◽  
Vol 88 (2) ◽  
pp. 170-177 ◽  
Author(s):  
Brage Bremset Hansen ◽  
Ronny Aanes ◽  
Bernt-Erik Sæther
Keyword(s):  
Rangifer Tarandus ◽  
High Arctic ◽  
Behavioural Plasticity ◽  
Short Term ◽  
Ground Ice ◽  
Mild Winter ◽  
Sparse Vegetation ◽  
Svalbard Reindeer ◽  
Trade Offs ◽  
Snowpack Properties

Increased frequency of ground-icing events is likely to influence population dynamics in arctic ungulates, but their behavioural responses remain unexplored. During a record-mild winter with heavy rainfall, we analysed snow and ice characteristics and foraging trade-offs by Svalbard reindeer ( Rangifer tarandus platyrhynchus Vrolik, 1829) on a semi-isolated, recently occupied range. Snow depths were well within thresholds for cratering, but >90% of low altitudes was covered by a thick ice coat on the ground (median thickness 9 cm). Different strategies to cope with these conditions appeared. Part of the population sought mountainous habitat with very sparse vegetation. Individuals remaining at lower altitudes either used sparsely vegetated, wind-blown ridges partially covered with ice, or apparently applied olfactory senses to locate vegetation in ice-free microhabitat beneath the snowpack. No feeding craters were covered by ground ice, compared with most nearby controls. Following ground-ice avoidance, vegetation rather than snowpack properties determined fine-scale crater selection. Even under such poor conditions, the presence of medium- to high-quality forage (dwarf willow ( Salix polaris Wahlenb.) and fruticose lichens) rather than low-digestible, high-biomass forage (mosses) influenced cratering decisions. Behavioural plasticity combined with a gradually depleted lichen resource can partly buffer the reindeer against predicted climate change, at least in the short-term.

scholarly journals Genetic variation in transferrin as a predictor for differentiation and evolution of caribou from eastern Canada

Rangifer ◽  
1991 ◽  
Vol 11 (2) ◽  
pp. 65 ◽  
Author(s):  
Knut H. Røed ◽  
Michael A. D. Ferguson ◽  
Michel Crête ◽  
Tom A. Bergerud
Keyword(s):  
High Frequency ◽  
Gel Electrophoresis ◽  
Rangifer Tarandus ◽  
Genetic Differences ◽  
The Other ◽  
Baffin Island ◽  
Eastern Canada ◽  
Low Frequencies ◽  
Svalbard Reindeer ◽  
Rangifer Tarandus Groenlandicus

Polycrylamide gel electrophoresis was used to analyse tranferrrin variation in caribou populations from Manitoba, Ontario, Québec/Labrador, and from Baffin Island, Northwest Territories in eastern Canada. The transferrin allele frequencies in these populations were compared with those previously reported for Canadian barren-ground caribou, Rangifer tarandus groenlandicus, Alaska caribou, R.t. grand, Peary caribou, R.t. pearyi, Svalbard reindeer, R.t. pla-tyrhynchus, and Eurasian tundra reindeer, R.t. tarandus. A total of twenty different alleles was detected in the analysed material, considerable genetic heterogeneity being detected among regions. Three alleles that were relatively common in caribou from Ontario, Manitoba and Québec/Labrador, were not present in R.t. grand, R.t. pearyi, R.t. tarandus or R.t. platyrhynchus, and present only at very low frequencies 'm R.t. groenlandicus. These findings, together with genetic identity analyses, suggest that the caribou in Manitoba, Ontario, and Québec/Labrador are mainly of the R.t. caribou type, and that little interbreeding has occurred with other subspecies. The large genetic distance in the transferrin locus between R.t. caribou and other subspecies of reindeer/caribou suggests that, during the Wisconsin glaciation the ancestral populations of R.t. caribou survived in a refugium different from that of the ancestral populations of the other subspecies. Significant genetic differences between Baffin Island caribou and all other populations were mainly due to the presence of one allele that was in high frequency in Baffin Island caribou, but that was absent, or present in very low frequencies, in all other reindeer/caribou populations. The genetic differences between Baffin Island caribou and the other subspecies were greater than the differences between several of the currently recognized subspecies.

scholarly journals Estimating the daily dry matter intake of Svalbard reindeer in late winter

Rangifer ◽  
1987 ◽  
Vol 7 (1) ◽  
pp. 29 ◽  
Author(s):  
Nicholas Tyler
Keyword(s):  
Dry Matter ◽  
Rangifer Tarandus ◽  
Subcutaneous Fat ◽  
High Arctic ◽  
Energy Requirements ◽  
Late Winter ◽  
Substantial Part ◽  
Svalbard Reindeer ◽  
Fat Reserves ◽  
Alternative Suggestion

Svalbard reindeer (Rangifer tarandus platyrhynchus) store large reserves of subcutaneous fat during summer and autumn which, it has been suggested, might be sufficient to meet a substantial part of their energy requirements during winter. An alternative suggestion, however, is that fat is not their main source of energy after all and, moreover, that the principal role of their fat reserves is for enhancing reproductive success rather than for substituting for forage (Tyler, in press). Is it realistic to suggest that these high arctic herbivores could meet the greater part of their energy requirements in winter by feeding, given that the aerial biomass of available forage in Svalbard in late winter is very low? This question was investigated by using a simple model to predict what rate of food intake Svalbard reindeer would have to achieve to maintain energy balance in late winter. The results were surprisingly low: pregnant and nonpregnant females could mett their daily energy demands by consuming 3.1 and 1.7 g dry matter per grazing minute, respectively. This supports the suggestion that Svalbard reindeer could live principally off forage in winter.

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