Evolutionary genetics and phylogeography of tassel-eared squirrels (Sciurus aberti)

Trip Lamb, Thomas R. Jones, Peter J. Wettstein

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

The tassel-eared squirrel (Sciurus aberti) is confined to a montane archipelago of mixed conifer forests in the American Southwest. Explanations for its fragmented distribution vary, invoking historical scenarios that stress late-Pleistocene vicariance, dispersal, or some combination thereof. To test among these hypotheses, we examined the phylogeography of S. aberti, as determined by variation in mtDNA restriction sites among 22 populations sampled range-wide. Genetic distance and maximum-parsimony analyses revealed three distinct lineages of mtDNA, which in turn form two major phylogeographic assemblages; eastern (Mexico; New Mexico-Colorado-Utah) and western (Arizona-southwestern New Mexico). Comparisons between the maximum-parsimony tree and an area cladogram of regional mountain ranges showed marked topological discordance, dismissing late-Pleistocene vicariance as a principal phylogeographic factor. Certain mtDNA data support the post-Pleistocene dispersal hypothesis, in which squirrels dispersed northward in conjunction with the rapid range expansion of ponderosa pines (Pinus ponderosa). However, divergence levels observed between assemblages (1.8%) also suggest a significant, underlying vicariant event responsible for major separation of lineages during the early Pleistocene. Thus, the evolutionary genetics of S. aberti has been influenced profoundly, and perhaps repeatedly, by climatic change during the Pleistocene.

Original languageEnglish (US)
Pages (from-to)117-133
Number of pages17
JournalJournal of Mammalogy
Volume78
Issue number1
StatePublished - 1997

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Phylogeography
Inflorescence
Sciurus
Sciuridae
Pinus ponderosa
phylogeography
squirrels
Mitochondrial DNA
mitochondrial DNA
inflorescences
Pleistocene
vicariance
Coniferophyta
Southwestern United States
mixed forests
Mexico
coniferous forests
genetic distance
mountains
climate change

Keywords

  • biogeography
  • mitochondrial DNA
  • phylogeography
  • Sciurus aberti
  • tassel-eared squirrel

ASJC Scopus subject areas

  • Animal Science and Zoology

Cite this

Lamb, T., Jones, T. R., & Wettstein, P. J. (1997). Evolutionary genetics and phylogeography of tassel-eared squirrels (Sciurus aberti). Journal of Mammalogy, 78(1), 117-133.

Evolutionary genetics and phylogeography of tassel-eared squirrels (Sciurus aberti). / Lamb, Trip; Jones, Thomas R.; Wettstein, Peter J.

In: Journal of Mammalogy, Vol. 78, No. 1, 1997, p. 117-133.

Research output: Contribution to journalArticle

Lamb, T, Jones, TR & Wettstein, PJ 1997, 'Evolutionary genetics and phylogeography of tassel-eared squirrels (Sciurus aberti)', Journal of Mammalogy, vol. 78, no. 1, pp. 117-133.
Lamb, Trip ; Jones, Thomas R. ; Wettstein, Peter J. / Evolutionary genetics and phylogeography of tassel-eared squirrels (Sciurus aberti). In: Journal of Mammalogy. 1997 ; Vol. 78, No. 1. pp. 117-133.
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