Chromosomal speciation in mice

A cytogenetic analysis of recombination

Valeria Merico, Mabel D. Giménez, Chiara Vasco, Maurizio Zuccotti, Jeremy B. Searle, Heidi C. Hauffe, Silvia Garagna

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Within species, populations differing by chromosomal rearrangements ("chromosomal races") may become reproductively isolated in association with reduced hybrid fertility due to meiotic aberrations. Speciation is also possible if hybridizing chromosomal races accumulate genetic differences because of reduced meiotic recombination in the heterozygous configuration in hybrids. Here, we examine recombination in pure races and hybrids within a model system for chromosomal speciation: the hybridization of the Poschiavo (CHPO) and Upper Valtellina (IUVA) chromosomal races of house mouse in Upper Valtellina, Italy. These races differ by Robertsonian fusions/whole-arm reciprocal translocations, such that hybrids produce a pentavalent meiotic configuration. We determined the number and position of the recombination points (using an antibody against the MutL homolog 1 [MLH1] protein) on synaptonemal complexes at pachytene in laboratory-reared CHPO, IUVA, and hybrid males, analyzing at least 112 spermatocytes per karyotypic group, up to a total of 534 spermatocytes. The mean ± standard deviation numbers of MLH1 foci per spermatocyte were 22.2 ± 3.2, 20.1 ± 2.9, 20.7 ± 2.3, and 21.9 ± 2.9 for CHPO, IUVA, CHPO × IUVA, and IUVA × CHPO, respectively. Altogether, 10,146 chromosome arms were examined, allowing multiple comparisons. Overall, recombination events were more frequently distal than proximal or interstitial. The average number of proximal MLH1 foci per chromosome arm decreased going from telocentric to metacentric bivalents to pentavalents (when present), which (together with other factors) influenced the average number of MLH1 foci per cell between CHPO, IUVA, and hybrid mice. The low frequency of proximal recombination in pentavalents of CHPO-IUVA hybrids may promote reproductive isolation between the CHPO and IUVA races, when coupled with reduced hybrid unfitness.

Original languageEnglish
Pages (from-to)523-533
Number of pages11
JournalChromosome Research
Volume21
Issue number5
DOIs
Publication statusPublished - Aug 2013

Fingerprint

Cytogenetic Analysis
Genetic Recombination
Spermatocytes
Synaptonemal Complex
Reproductive Isolation
Chromosomes, Human, Pair 10
Italy
Fertility
Chromosomes
MutL Protein Homolog 1
Antibodies
Population

Keywords

  • Hybrid zone
  • MLH1
  • Mus musculus
  • Robertsonian translocation
  • Spermatocytes

ASJC Scopus subject areas

  • Genetics

Cite this

Merico, V., Giménez, M. D., Vasco, C., Zuccotti, M., Searle, J. B., Hauffe, H. C., & Garagna, S. (2013). Chromosomal speciation in mice: A cytogenetic analysis of recombination. Chromosome Research, 21(5), 523-533. https://doi.org/10.1007/s10577-013-9377-5

Chromosomal speciation in mice : A cytogenetic analysis of recombination. / Merico, Valeria; Giménez, Mabel D.; Vasco, Chiara; Zuccotti, Maurizio; Searle, Jeremy B.; Hauffe, Heidi C.; Garagna, Silvia.

In: Chromosome Research, Vol. 21, No. 5, 08.2013, p. 523-533.

Research output: Contribution to journalArticle

Merico, V, Giménez, MD, Vasco, C, Zuccotti, M, Searle, JB, Hauffe, HC & Garagna, S 2013, 'Chromosomal speciation in mice: A cytogenetic analysis of recombination', Chromosome Research, vol. 21, no. 5, pp. 523-533. https://doi.org/10.1007/s10577-013-9377-5
Merico V, Giménez MD, Vasco C, Zuccotti M, Searle JB, Hauffe HC et al. Chromosomal speciation in mice: A cytogenetic analysis of recombination. Chromosome Research. 2013 Aug;21(5):523-533. https://doi.org/10.1007/s10577-013-9377-5
Merico, Valeria ; Giménez, Mabel D. ; Vasco, Chiara ; Zuccotti, Maurizio ; Searle, Jeremy B. ; Hauffe, Heidi C. ; Garagna, Silvia. / Chromosomal speciation in mice : A cytogenetic analysis of recombination. In: Chromosome Research. 2013 ; Vol. 21, No. 5. pp. 523-533.
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