Complex evolution of sex chromosomes in Gerbillidae (Rodentia)

Viegas‐Péquignot, Evani; Benazzou, Touria; Dutrillaux, B.; Petter, F.

doi:10.1159/000131804

Cited by 38 publications

(25 citation statements)

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“…; Dobigny et al, manuscript submitted for publication; present study) is also characteristic of numerous taxa within the subfamily Gerbillinae (Viegas-Péquignot et al, 1982Volobouev et al, 1995). Unfortunately, data on genetic differentiation are lacking for most of them, and therefore little is known about the rate of karyotypic changes and their correlation with the speciation process.…”

Section: Discussionmentioning

confidence: 63%

Explosive chromosome evolution and speciation in the gerbil genus <i>Taterillus</i> (Rodentia, Gerbillinae): a case of two new cryptic species

Dobigny

Анискин

Volobouev

2002

Cytogenet Genome Res

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The five morphologically sibling gerbil species of the genus Taterillus in West Africa were first identified from karyotypes. These species possess an XX/XY₁Y₂ sex-chromosome system and are characterized by significant karyotypic reorganization, thus making them a suitable model for studying the role of chromosomal rearrangements in the speciation process. We present here a description of two new cytotypes, Taterillus sp. 1 and Taterillus sp. 2, from the Lake Chad area, the former having a 2n = 22/23, NFa = 40, and the latter 2n = 24/25, NFa = 44. Comparison of their G- and C- banding patterns with those of T. pygargus (2n = 22/23, NFa = 38/40), examined in an earlier paper, revealed that all three species differ from each other by 7 to 11 chromosomal rearrangements, comprising tandem translocations, pericentric inversions, and Robertsonian metacentrics displaying monobrachial homology. Meiotic configurations formed in potential hybrids among any of these three forms would consist of complex rings and chains, alone or in combination, resulting, as expected, in a significant disruption of gametogenesis. These results provide support for assigning Taterillus sp. 1 and Taterillus sp. 2 to two different biological species, which, as demonstrated by our preliminary molecular studies, would have emerged recently. Possible factors responsible for the rapid karyotypic evolution and speciation in this West African gerbil complex are discussed.

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Section: Discussionmentioning

confidence: 63%

Explosive chromosome evolution and speciation in the gerbil genus <i>Taterillus</i> (Rodentia, Gerbillinae): a case of two new cryptic species

Dobigny

Анискин

Volobouev

2002

Cytogenet Genome Res

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“…This is in con trast to several other mammalian species which show an increase in heterochromatin coincident with Xand/or Y-autosome translocations (Benirschke et al, 1980;Ma et al, 1980;Dutrillaux et al, 1981). Viegas-Pequignot et al (1982) suggest that C-band heterochromatin may effectively separate a translo cated autosome from the original X chromosome and prevent inactivation of the translocated autosome. The translocated autosomal portion of the X would thus behave autonomously from the remainder of the X chromosome.…”

Section: Discussionmentioning

confidence: 99%

Sex chromosome-autosome translocations in the leaf-nosed bats, family Phyllostomidae

Tucker

1986

Cytogenet Genome Res

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Mitotic analyses using RBA- and C-banding were performed on Stenodermatine bats with X-autosome (XY₁Y₂) and X- and Y- autosome (neo-XY) translocations. RBA-banded metaphases of females revealed differential replication of the inactive X chromosome. An early replicating band comprises the short arm of the X, and an intermediate replicating band is located interstitially on sthe long arm. The early replicating short arm has a homologous counterpart either in the form of a free autosome (the Y₂) or as part of the Y. Both the “autosomal” short arm of the X and its homologue fused to the Y are C-band negative and behave autonomously from the remainder of the sex chromosomes. They are separated from X and Y chromatin by centromeric heterochromatin which presumably acts as a barrier. The intermediate replicating region of the long arm of the X is also present in the subfamily Phyllostominae. In both subfamilies this region lacks a homologous counterpart. However, it may also represent a translocated autosome which, unlike the short arm of the X, is not separated from the inactive X by centromeric heterochromatin. Its intermediate replication time may represent a retarded replication due to its juxtaposition to late replicating X chromatin. These data are discussed in light of the theory of the evolution of sex chromosome heteromorphism, specifically as it applies to mammals.

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“…On the other hand, some species present sex chromosomes with synapsis and recombination, as in G. chiesmani, G. nigeriae, G. hoogstrali, and Taterillus pygargus [31]. However, the synapsing regions in these species seem to be originated, as in many other eutherian mammals, by recent translocations of autosomal segments to both the X and Y chromosomes [49,50]. Previous analyses on the sex chromosomal phylogeny of Gerbillidae have shown that the X chromosome of M. unguiculatus could be one of the most primitive among this family [49], reinforcing the idea that the asynaptic condition of sex chromosomes would be an ancient feature of this group.…”

Section: Lack Of Par Is Responsible For the Asynaptic Nature Of Sex Cmentioning

confidence: 99%

Meiotic pairing and segregation of achiasmate sex chromosomes in eutherian mammals: the role of SYCP3 protein

et al. 2005

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In most eutherian mammals, sex chromosomes synapse and recombine during male meiosis in a small region called pseudoautosomal region. However in some species sex chromosomes do not synapse, and how these chromosomes manage to ensure their proper segregation is under discussion. Here we present a study of the meiotic structure and behavior of sex chromosomes in one of these species, the Mongolian gerbil (Meriones unguiculatus). We have analyzed the location of synaptonemal complex (SC) proteins SYCP1 and SYCP3, as well as three proteins involved in the process of meiotic recombination (RAD51, MLH1, and c-H2AX). Our results show that although X and Y chromosomes are associated at pachytene and form a sex body, their axial elements (AEs) do not contact, and they never assemble a SC central element. Furthermore, MLH1 is not detected on the AEs of the sex chromosomes, indicating the absence of reciprocal recombination. At diplotene the organization of sex chromosomes changes strikingly, their AEs associate end to end, and SYCP3 forms an intricate network that occupies the Y chromosome and the distal region of the X chromosome long arm. Both the association of sex chromosomes and the SYCP3 structure are maintained until metaphase I. In anaphase I sex chromosomes migrate to opposite poles, but SYCP3 filaments connecting both chromosomes are observed. Hence, one can assume that SYCP3 modifications detected from diplotene onwards are correlated with the maintenance of sex chromosome association. These results demonstrate that some components of the SC may participate in the segregation of achiasmate sex chromosomes in eutherian mammals.

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Complex evolution of sex chromosomes in Gerbillidae (Rodentia)

Cited by 38 publications

References 0 publications

Explosive chromosome evolution and speciation in the gerbil genus <i>Taterillus</i> (Rodentia, Gerbillinae): a case of two new cryptic species

Explosive chromosome evolution and speciation in the gerbil genus <i>Taterillus</i> (Rodentia, Gerbillinae): a case of two new cryptic species

Sex chromosome-autosome translocations in the leaf-nosed bats, family Phyllostomidae

Meiotic pairing and segregation of achiasmate sex chromosomes in eutherian mammals: the role of SYCP3 protein

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