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Träfflista för sökning "WFRF:(Heide Jorgensen M P) "

Search: WFRF:(Heide Jorgensen M P)

  • Result 1-6 of 6
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2.
  • Ameen, Carly, et al. (author)
  • Specialized sledge dogs accompanied Inuit dispersal across the North American Arctic
  • 2019
  • In: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 286:1916
  • Journal article (peer-reviewed)abstract
    • Domestic dogs have been central to life in the North American Arctic for millennia. The ancestors of the Inuit were the first to introduce the widespread usage of dog sledge transportation technology to the Americas, but whether the Inuit adopted local Palaeo-Inuit dogs or introduced a new dog population to the region remains unknown. To test these hypotheses, we generated mitochondrial DNA and geometric morphometric data of skull and dental elements from a total of 922 North American Arctic dogs and wolves spanning over 4500 years. Our analyses revealed that dogs from Inuit sites dating from 2000 BP possess morphological and genetic signatures that distinguish them from earlier Palaeo-Inuit dogs, and identified a novel mitochondrial clade in eastern Siberia and Alaska. The genetic legacy of these Inuit dogs survives today in modern Arctic sledge dogs despite phenotypic differences between archaeological and modern Arctic dogs. Together, our data reveal that Inuit dogs derive from a secondary pre-contact migration of dogs distinct from Palaeo-Inuit dogs, and probably aided the Inuit expansion across the North American Arctic beginning around 1000 BP.
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3.
  • Garde, E., et al. (author)
  • Life history parameters of narwhals (Monodon monoceros) from Greenland
  • 2015
  • In: Journal of Mammalogy. - : Oxford University Press (OUP). - 0022-2372 .- 1545-1542. ; 96:4, s. 866-879
  • Journal article (peer-reviewed)abstract
    • Life history parameters for narwhals (Monodon monoceros) were estimated based on age estimates from aspartic acid racemization of eye lens nuclei. Eyes, reproductive organs, and measures of body lengths were collected from 282 narwhals in East and West Greenland in the years 1993, 2004, and 2007-2010. Age estimates were based on the racemization of L-aspartic acid to D-aspartic acid in the nucleus of the eye lens. The ratio of D- and L-enantiomers was measured using high-performance liquid chromatography. The age equation used, 420.32X - 24.02 center dot year where X is the D/L ratio, was determined from data from Garde et al. (2012). Asymptotic body length was estimated to be 405 +/- 5.8cm for females and 462 +/- 16.2cm for males from East Greenland, and 399 +/- 5.9cm for females and 456 +/- 6.9cm for males from West Greenland. Due to several indeterminant age class estimates, age at sexual maturity was subjectively assessed based on data from reproductive organs and was estimated to be 8-9 years for females and 12-20 years for males. Pregnancy rates for East and West Greenland were estimated to be 0.38-0.42 and 0.38, respectively. Maximum life span expectancy was found to be approximately 100 years. A population projection matrix was parameterized with the data on age structure and fertility rates. The annual rate of increase of narwhals in East Greenland was estimated to be 3.8% while narwhals in West Greenland had a rate of increase at 2.6%.
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4.
  • Härkönen, T., et al. (author)
  • Rates of increase in age-structured populations: a lesson from the European harbour seals
  • 2002
  • In: Canadian Journal of Zoology-Revue Canadienne De Zoologie. - 0008-4301. ; 80:9, s. 1498-1510
  • Journal article (peer-reviewed)abstract
    • Behavioural differences among population segments coupled with the transient dynamics of perturbed population structures lead to severely biased estimates of the intrinsic rates of increase in natural populations. This phenomenon is expected to occur in most populations that are structured by age, sex, state, or rank. The 1988 epizootic in European harbour seals (Phoca vitulina) perturbed the population composition radically. Detailed documentation of mass mortality, 20 years of population surveys, and data on age- and sex-specific behaviour were used to quantify biases in the observed rate of increase (lambda(obs.)), which in many areas substantially exceeded the "maximum rate of increase". This is serious, since lambda(obs.) is a key parameter, for example, in estimating potential biological removal or modelling population dynamics. For populations where the underlying age and sex composition is unknown, we suggest that data on fecundity and survival rates be used to find the upper theoretical rate of population increase. We found that the intrinsic rates of increase (lambda(1)) in populations of true seals with even sex ratios and stable age structures cannot exceed 13% per year (lambda(1max.) = 1.13). Frequently reported larger values are indicative of nonstable population structures or populations affected by migrations.
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5.
  • Sinding, Mikkel-Holger S., et al. (author)
  • Arctic-adapted dogs emerged at the Pleistocene-Holocene transition
  • 2020
  • In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 368:6498
  • Journal article (peer-reviewed)abstract
    • Although sled dogs are one of the most specialized groups of dogs, their origin and evolution has received much less attention than many other dog groups. We applied a genomic approach to investigate their spatiotemporal emergence by sequencing the genomes of 10 modern Greenland sled dogs, an similar to 9500-year-old Siberian dog associated with archaeological evidence for sled technology, and an similar to 33,000-year-old Siberian wolf. We found noteworthy genetic similarity between the ancient dog and modern sled dogs. We detected gene flow from Pleistocene Siberian wolves, but not modern American wolves, to present-day sled dogs. The results indicate that the major ancestry of modern sled dogs traces back to Siberia, where sled dog-specific haplotypes of genes that potentially relate to Arctic adaptation were established by 9500 years ago.
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6.
  • Sinding, Mikkel-Holger S., et al. (author)
  • Population genomics of grey wolves and wolf-like canids in North America
  • 2018
  • In: PLOS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 14:11
  • Journal article (peer-reviewed)abstract
    • North America is currently home to a number of grey wolf (Canis lupus) and wolf-like canid populations, including the coyote (Canis latrans) and the taxonomically controversial red, Eastern timber and Great Lakes wolves. We explored their population structure and regional gene flow using a dataset of 40 full genome sequences that represent the extant diversity of North American wolves and wolf-like canid populations. This included 15 new genomes (13 North American grey wolves, 1 red wolf and 1 Eastern timber/Great Lakes wolf), ranging from 0.4 to 15x coverage. In addition to providing full genome support for the previously proposed coyote-wolf admixture origin for the taxonomically controversial red, Eastern timber and Great Lakes wolves, the discriminatory power offered by our dataset suggests all North American grey wolves, including the Mexican form, are monophyletic, and thus share a common ancestor to the exclusion of all other wolves. Furthermore, we identify three distinct populations in the high arctic, one being a previously unidentified "Polar wolf" population endemic to Ellesmere Island and Greenland. Genetic diversity analyses reveal particularly high inbreeding and low heterozygosity in these Polar wolves, consistent with long-term isolation from the other North American wolves.
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