test Browse by Author Names Browse by Titles of Works Browse by Subjects of Works Browse by Issue Dates of Works

Advanced Search
& Collections
Issue Date   
Sign on to:   
Receive email
My Account
authorized users
Edit Profile   
About T-Space   

T-Space at The University of Toronto Libraries >
University of Toronto at Scarborough >
Biological Sciences >
Biology >

Please use this identifier to cite or link to this item: http://hdl.handle.net/1807/462

Title: Chromosomal and mitochondrial DNA variation in four laboratory populations of collared lemmings (dicrostonyx)
Authors: Engstrom, Mark
Baker, Allan
Eger, Judith
Boonstra, Rudy
Brooks, Ronald
Issue Date: 1992
Publisher: National Research Council Canada
Citation: Can. J. Zool. 71: 42-48
Abstract: Genetic differentiation among populations and speciation in Dicrostonyx is hypothesized to have resulted from either allopatric divergence in glacial refugia during the Wisconsin or sympatric processes uncorrelated with refugial isolation. We examined chromosomal and mitochondrial DNA variation in four laboratory colonies, representing three species, in a preliminary evaluation of these hypotheses. Chromosomal variation is extensive among populations, diploid numbers ranging from 38 to 50. Autosomal variation appears to be due primarily to Robertsonian rearrangements and additions of supernumerary chromosomes, and is geographically unpatterned. Sex chromosome morphology is geographically structured and correlated with proposed southern and northern refugia. Restriction fragment analysis of mitochondrial DNA revealed two ancient, divergent genotypic assemblages, corresponding to geographic distributions of sex chromosomes. Autosomal variation, and any resulting reproductive isolation, probably is recent and uncorrelated with refugial history, whereas divergence of sex chromosomes and disparate mitochondrial assemblages likely predate the Wisconsin.
URI: http://hdl.handle.net/1807/462
Appears in Collections:Biology

Files in This Item:

File Description SizeFormat
Chromosomal_mitochondrial_variation.pdf122.58 kBAdobe PDF

Items in T-Space are protected by copyright, with all rights reserved, unless otherwise indicated.