TY - JOUR

T1 - Chromosome synapsis and recombination in male hybrids between two chromosome races of the common shrew (Sorex araneus L., Soricidae, Eulipotyphla)

AU - Belonogova, Nadezhda M.

AU - Polyakov, Andrei V.

AU - Karamysheva, Tatyana V.

AU - Torgasheva, Anna A.

AU - Searle, Jeremy B.

AU - Borodin, Pavel M.

N1 - Publisher Copyright: © 2017 by the authors; Licensee MDPI, Basel, Switzerland.

PY - 2017/10/20

Y1 - 2017/10/20

N2 - 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.

AB - 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.

KW - Common shrew

KW - Hybrids

KW - Meiotic chromosomes

KW - MLH1

KW - Sorex araneus

KW - Synaptonemal complex

KW - PACHYTENE CHECKPOINT

KW - MONOBRACHIAL CENTRIC FUSIONS

KW - REDUCED GENE FLOW

KW - HOUSE MOUSE

KW - ZONE

KW - SIBERIA

KW - hybrids

KW - synaptonemal complex

KW - meiotic chromosomes

KW - SYNAPTONEMAL COMPLEXES

KW - common shrew

KW - KARYOTYPIC RACES

KW - SPECIATION

KW - MEIOSIS

UR - http://www.scopus.com/inward/record.url?scp=85032573857&partnerID=8YFLogxK

U2 - 10.3390/genes8100282

DO - 10.3390/genes8100282

M3 - Article

C2 - 29053571

AN - SCOPUS:85032573857

VL - 8

JO - Genes

JF - Genes

SN - 2073-4425

IS - 10

M1 - 282

ER -