The forbidden doubling: exploring rare spermatocyte polyploidy in mammals

By

Matveevsky, Sergey
Kolomiets, Oxana L.
Grishaeva, Tatiana
Bogdanov, Aleksey
Tambovtseva, Valentina
Bakloushinskaya, Irina

Type

Article

Date of Publication

2026-1-23

Original Publication

Comparative cytogenetics : international journal of plant & animal cytogenetics, karyosystematics and molecular systematics

Volume

20

Pages

67--85

Subjects

gametogenesis , meiotic prophase I , quadrivalent , synaptonemal complex , tetraploidy

Contributed by

Pensoft Publishers

Language

English

Published by

St. Petersburg, Russia [Published] with technical support of Zoological Institute RAS [2007]-

Identifiers

DOI: https://doi.org/10.3897/compcytogen.20.177662

 

Abstract

<br> We first studied several rare cases of over-diploid spermatocyte emergence using advanced immunocytochemical methods and a cross-species approach in subterranean rodents<br> Ellobius tancrei<br> (Blasius, 1884),<br> E. alaicus<br> Vorontsov et al., 1969,<br> E. talpinus<br> (Pallas, 1770), and<br> Nannospalax leucodon<br> (Nordmann, 1840) (all belong to the order Rodentia). The tetraploid spermatocytes exhibited specific features during meiotic prophase I, including symmetric and asymmetric chromosome quadrivalents with partner-switching, extended asynapsis, altered recombination patterns, and variable chromatin inactivation. These anomalies suggest that meiotic checkpoints, which are potentially triggered by failed synapsis or incomplete sex chromosome silencing, may act to prevent progression of polyploid spermatocytes. However, the quadrivalents assembled shelterin complexes at chromosome ends, as observed in<br> E. talpinus<br> , and these ends were connected to the nuclear envelope through the linker of nucleoskeleton and cytoskeleton (LINC) complex, as observed in<br> E. alaicus<br> , similarly to normal spermatocytes.<br>