Chromosome synapsis and recombination in simple and complex chromosomal heterozygotes of tuco-tuco (Ctenomys talarum: Rodentia: Ctenomyidae): Rodentia: Ctenomyidae)

Ekaterina A. Basheva, Anna A. Torgasheva, Maria Jimena Gomez Fernandez, Emma Boston, Patricia Mirol, Pavel M. Borodin*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

The chromosomal speciation hypothesis suggests that irregularities in synapsis, recombination, and segregation in heterozygotes for chromosome rearrangements may restrict gene flow between karyotypically distinct populations and promote speciation. Ctenomys talarum is a South American subterranean rodent inhabiting the coastal regions of Argentina, whose populations polymorphic for Robertsonian and tandem translocations seem to have a very restricted gene flow. To test if chromosomal differences are involved in isolation among its populations, we examined chromosome pairing, recombination, and meiotic silencing of unsynapsed chromatin in male meiosis of simple and complex translocation heterozygotes using immunolocalization of the MLH1 marking mature recombination nodules and phosphorylated histone γH2A.X marking unrepaired double-strand breaks. We observed small asynaptic areas labeled by γH2A.X in pericentromeric regions of the chromosomes involved in the trivalents and quadrivalents. We also observed a decrease of recombination frequency and a distalization of the crossover distribution in the heterozygotes and metacentric homozygotes compared to acrocentric homozygotes. We suggest that the asynapsis of the pericentromeric regions are unlikely to induce germ cell death and decrease fertility of the heterozygotes; however, suppressed recombination in pericentromeric areas of the multivalents may reduce gene flow between chromosomally different populations of the Talas tuco-tuco.

Original languageEnglish
Pages (from-to)351-363
Number of pages13
JournalChromosome Research
Volume22
Issue number3
Early online date13 Jun 2014
DOIs
Publication statusPublished - Sep 2014

Keywords

  • Meiosis
  • synaptonemal complex
  • Robertsonian translocation
  • whole-arm reciprocal translocation
  • MLH1
  • SYCP3
  • gammaH2A. X
  • gene flow
  • chromosome speciation
  • MUS-MUSCULUS-DOMESTICUS
  • SHREW SUNCUS-MURINUS
  • GENUS CTENOMYS
  • SOREX-ARANEUS
  • HOUSE MOUSE
  • ROBERTSONIAN HETEROZYGOTES
  • COMMON SHREW
  • SUBTERRANEAN RODENTS
  • CROSSING-OVER
  • HYBRID ZONE

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