Affordable Access

Male common shrews (Sorex araneus) with long meiotic chain configurations can be fertile: implications for chromosomal models of speciation.

Authors
  • Mercer, S J1
  • Wallace, B M
  • Searle, J B
  • 1 Department of Zoology, University of Oxford, UK.
Type
Published Article
Journal
Cytogenetics and cell genetics
Publication Date
Jan 01, 1992
Volume
60
Issue
1
Pages
68–73
Identifiers
PMID: 1582263
Source
Medline
License
Unknown

Abstract

Two chromosomal races of common shrews (Sorex araneus) were crossed in captivity to generate chain VII-forming complex Robertsonian heterozygotes. Meiosis and gametogenesis were studied in three male hybrids. Regular chain VII configurations were observed at both pachytene and diakinesis/metaphase I, although in many pachytene spreads the chain configuration was incomplete (the basis of this peculiarity is unknown). From metaphase II counts, the frequency of anaphase I nondisjunction in the complex heterozygotes was estimated to be 13%. Germ-cell death in the chain VII-forming complex heterozygotes was 22% greater than it was in controls, but this difference is unlikely to have greatly influenced the capacity of the heterozygotes to sire offspring. Thus, the fecundity of these complex heterozygous common shrews would probably have been only slightly reduced relative to homozygous or simple heterozygous shrews. These results call into question the generality of speciation models based on the presumed sterility of complex heterozygotes.

Report this publication

Statistics

Seen <100 times