English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The formation of hybrid sterility is an important stage of speciation. The voles of the genus  Microtus , which is the most speciose genus of rodents, provide a good model for studying the cytological mechanisms of hybrid sterility. The voles of the “ mystacinus ” group of the subgenus  Microtus  (2 n  = 54) comprising several recently diverged forms with unclear taxonomic status are especially interesting. To resolve the taxonomic status of  Microtus mystacinus  and  Microtus kermanensis , we crossed both with  Microtus rossiaemeridionalis , and  M. kermanensis  alone with  Microtus arvalis  “obscurus” and  M. transcaspicus  and examined the reproductive performance of their F1 hybrids. All interspecies male hybrids were sterile. Female  M. kermanensis  ×  M. arvalis  and  M. kermanensis  ×  M. transcaspicus  hybrids were sterile as well. Therefore,  M. mystacinus ,  M. kermanensis , and  M. rossiaemeridionalis  could be considered valid species. To gain an insight into the cytological mechanisms of male hybrid sterility, we carried out a histological analysis of spermatogenesis and a cytological analysis of chromosome synapsis, recombination, and epigenetic chromatin modifications in the germ cells of the hybrids using immunolocalization of key meiotic proteins. The hybrids showed wide variation in the onset of spermatogenesis arrest stage, from mature (although abnormal) spermatozoa to spermatogonia only. Chromosome asynapsis was apparently the main cause of meiotic arrest. The degree of asynapsis varied widely across cells, individuals, and the crosses—from partial asynapsis of several small bivalents to complete asynapsis of all chromosomes. The asynapsis was accompanied by a delayed repair of DNA double-strand breaks marked by RAD51 antibodies and silencing of unpaired chromatin marked by γH2A.X antibodies. Overall, the severity of disturbances in spermatogenesis in general and in chromosome synapsis in particular increased in the hybrids with an increase in the phylogenetic distance between their parental species.

frontiers in genetics

Reproductive Isolation Between Taxonomically Controversial Forms of the Gray Voles (Microtus, Rodentia; Arvicolinae): Cytological Mechanisms and Taxonomical Implications