Genes 2017, 8(10), 282; https://doi.org/10.3390/genes8100282
Chromosome Synapsis and Recombination in Male Hybrids between Two Chromosome Races of the Common Shrew (Sorex araneus L., Soricidae, Eulipotyphla)
Nadezhda M. Belonogova 1,†, Andrei V. Polyakov 1,†, Tatyana V. Karamysheva 1, Anna A. Torgasheva 1,2, Jeremy B. Searle 3 and Pavel M. Borodin 1,2,*
1
Institute of Cytology and Genetics, Russian Academy of Sciences, Siberian Department, Novosibirsk 630090, Russia
2
Novosibirsk State University, Department of Cytology and Genetics, Novosibirsk 630090, Russia
3
Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
â€
These authors contributed equally to this work.
*
Author to whom correspondence should be addressed.
Received: 31 August 2017 / Revised: 8 October 2017 / Accepted: 17 October 2017 / Published: 20 October 2017
(This article belongs to the Special Issue Chromosomal Evolution)
Abstract
Hybrid zones between chromosome races of the common shrew (Sorex araneus) provide exceptional models to study the potential role of chromosome rearrangements in the initial steps of speciation. The Novosibirsk and Tomsk races differ by a series of Robertsonian fusions with monobrachial homology. They form a narrow hybrid zone and generate hybrids with both simple (chain of three chromosomes) and complex (chain of eight or nine) synaptic configurations. Using immunolocalisation of the meiotic proteins, we examined chromosome pairing and recombination in males from the hybrid zone. Homozygotes and simple heterozygotes for Robertsonian fusions showed a low frequency of synaptic aberrations (<10%). The carriers of complex synaptic configurations showed multiple pairing abnormalities, which might lead to reduced fertility. The recombination frequency in the proximal regions of most chromosomes of all karyotypes was much lower than in the other regions. The strong suppression of recombination in the pericentromeric regions and co-segregation of race specific chromosomes involved in the long chains would be expected to lead to linkage disequilibrium between genes located there. Genic differentiation, together with the high frequency of pairing aberrations in male carriers of the long chains, might contribute to maintenance of the narrow hybrid zone. View Full-TextKeywords:
common shrew; meiotic chromosomes; Sorex araneus; synaptonemal complex; hybrids; MLH1
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Belonogova, N.M.; Polyakov, A.V.; Karamysheva, T.V.; Torgasheva, A.A.; Searle, J.B.; Borodin, P.M. Chromosome Synapsis and Recombination in Male Hybrids between Two Chromosome Races of the Common Shrew (Sorex araneus L., Soricidae, Eulipotyphla). Genes 2017, 8, 282.
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