Sex chromosomes, sex determination, and sex-linked sequences in Microtidae

  title={Sex chromosomes, sex determination, and sex-linked sequences in Microtidae},
  author={Juan Alberto Marchal and Manuel de Jes{\'u}s Acosta and M{\'o}nica Bullejos and Rafael D{\'i}az de la Guardia and A. S{\'a}nchez},
  journal={Cytogenetic and Genome Research},
  pages={266 - 273}
The Arvicolidae is a widely distributed rodent group with several interesting characteristics in their sex chromosomes. Here, we summarize the actual knowledge of some of these characteristics. This mammalian group has species with abnormal sex determination systems. In fact, some species present the same karyotype in both males and females, with total absence of a Y chromosome, and hence of SRY and ZFY genes. Other species present fertile, sex-reversed XY females, generally due to mutations… 

Comparative Analysis by Chromosome Painting of the Sex Chromosomes in Arvicolid Rodents

This study has shown a new relationship between the giant sex chromosomes of 2 species, MicroTus agrestis and Microtus cabrerae, that is, both X and Y share a novel region of common sequences in the euchromatin that is not present in the other species analysed.

X chromosome painting in Microtus: Origin and evolution of the giant sex chromosomes

The X chromosome painting results on autosomes of several species suggest that, during karyotypic evolution of the genus Microtus, some rearrangements have probably occurred between sex chromosomes and autosomes.

Structural and Evolutionary Relationships in the Giant Sex Chromosomes of Three Microtus Species

An intra- and interspecific analysis of the molecular composition of the heterochromatic blocks in three species with giant sex chromosomes reinforces the idea that certain similarities in the original organization of these X chromosomes could have facilitated their later enlargement.

A repeat DNA sequence from the Y chromosome in species of the genus Microtus

The authors' data suggest that the mechanism of heterochromatin amplification operating on the sex chromosomes could have been different in each species since the repeated sequences of the gonosomal heterochromaatic blocks in M. cabrerae and M. agrestis are different, and the absence of this sequence in the mouse genome indicates that its evolutionary origin could be recent.

One more Microtus species with asynaptic sex chromosomes

This is the first finding for the European pine vole, Microtus subterraneus, with asynaptic sex chromosomes (2n=52), and from summarized data it appears that two-thirds of the studied species, mainly from MicroTus and Terricola subgenera, possess asynptic sex chromosomes.

Distribution of L1-retroposons on the giant sex chromosomes of Microtus cabrerae (Arvicolidae, Rodentia): functional and evolutionary implications

It is proposed that the main factors responsible for the L1 distribution on the mammalian sex chromosomes are the heterochromatic nature of the Y chromosome and the possible role of L1 sequences during the X-inactivation process.

Extensive Sex Chromosome Polymorphism of Microtus thomasi/Microtus atticus Species Complex Associated with Cryptic Chromosomal Rearrangements and Independent Accumulation of Heterochromatin

This work proposed that a similar polymorphism variation combined with random drift fixing the biggest sex chromosomes could have occurred in the origin of some of the actual Microtus species with giant sex chromosomes.

Sex chromosome variability outlines the pathway to the chromosomal evolution in Microtus thomasi (Rodentia, Arvicolinae)

It is proposed that the last glaciation must have restricted M. thomasi to a refugium in southern Peloponnesus, which is proven today by comparatively larger sex chromosomes in the northern populations of ‘thomasi’ and ‘atticus’ in Greece than in their southern populations.

Molecular Composition of Heterochromatin and Its Contribution to Chromosome Variation in the Microtus thomasi/Microtus atticus Species Complex

The voles of the Microtus thomasi/M. atticus species complex demonstrate a remarkable variability in diploid chromosomal number (2n = 38–44 chromosomes) and sex chromosome morphology. In the current

Sex chromosome polymorphism in Bulgarian populations of Microtus guentheri (Danford & Alston, 1880)

The sex chromosomes exhibit interpopulation variation in morphology and heterochromatin patterns, which probably originated as a result of random amplification of sequences as have been proposed in other species of the genus Microtus.



Sex determination in Ellobius lutescens: The story of an enigma

Evidence that Zfy is also missing in Ellobius lutescens and E. tancrei is reported, a finding from which it is concluded that the entire Y chromosome has been lost from these species.

Multiple mono- and polymorphic Y-linked copies of the SRY HMG-box in Microtidae

The SRY HMG-box is investigated in nine species of the family Microtidae, finding the presence of multiple mono- or polymorphic copies of the SRY gene located on the Y chromosome in eight of these species.

Multiple, polymorphic copies of SRY in both males and females of the vole Microtus cabrerae.

It is concluded that this gene is not male-specific in M. cabrerae, as it is present in multiple, polymorphic copies in both males and females, and southern blots suggest that most of the extra copies of SRY are X-linked.

Characterization and sequencing of the sex determining region Y gene (Sry) in Akodon (Cricetidae) species with sex reversed females

The development of fully fertile ovaries in XY Akodon females is not due to a deletion of Sry or to mutations in the Sry segment analyzed in this report, and sex reversal may be due to abnormal expression of this gene at the stage of gonadal differentiation.

Achiasmatic giant sex chromosomes in the vole Microtus cabrerae (Rodentia, Microtidae).

The results suggest that the heterochromatic blocks are not involved in the lack of synapsis and that asynapsis is a cytological feature common to all species of the family Microtidae.

Sex chromosomes pairing in two Arvicolidae species: Microtus nivalis and Arvicola sapidus.

It is proposed that synaptic sex chromosomes were the ancestral condition in the family Arvicolidae, including the genus Microtus, and the phylogenetic origin of the asynaptic sex chromosomes in the genusMicrotus would have arisen once in the lineage that originated the species M. arvalis/agrestis and related species.

Unusual distribution of Zfy and Zfx sequences on the sex chromosomes of the wood lemming, a species exhibiting XY sex reversal.

It has been postulated that expression of the Zfy (ZFY) gene may be important for spermatogenesis, and the lack of sufficient Zfy transcripts in the testis of the adult wood lemming has any impact on sPermatogenesis in this species is still to be elucidated by further studies.

Molecular and cytogenetic characterization of highly repeated DNA sequences in the vole Microtus cabrerae

The hypothesis that the heterochromatic blocks from the sex chromosomes of different species are evolving independently and they probably have the genetic capacity to amplify and retain different satellite DNAs is supported.

Fertile XO males and females in the varying lemming, Dicrostonyx torquatus pall. (1779)

It has been shown that the sex of XO specimens depends on a genetic factor which displays two alternative forms, most likely X-linked, and the XO lemmings possessing the m-form develop as males; those carrying the f- form develop as females.

Mapping the SRY gene in Microtus cabrerae: a vole species with multiple SRY copies in males and females.

The chromosomal localization of SRY gene copies in this species by fluorescent in situ hybridization (FISH) is presented, showing the presence of multiple polymorphic copies of this gene in both males and females of the vole species Microtus cabrerae.