Evolutionary rearrangements of X chromosomes in voles (Arvicolinae, Rodentia)

Svetlana A Romanenko,Yulia E Fedorova,Natalya A Serdyukova,Alexander S Graphodatsky,Roscoe Stanyon,Marco Zaccaroni

doi:10.1038/s41598-020-70226-4

Abstract

Euchromatic segments of the X chromosomes of placental mammals are the most conservative elements of the karyotype, only rarely subjected to either inter- or intrachromosomal rearrangements. Here, using microdissection-derived set of region-specific probes of Terricola savii we detailed the evolutionary rearrangements found in X chromosomes in 20 vole species (Arvicolinae, Rodentia). We show that the evolution of X chromosomes in this taxon was accompanied by multiple para- and pericentric inversions and centromere shifts. The contribution of intrachromosomal rearrangements to the karyotype evolution of Arvicolinae species was approximately equivalent in both the separate autosomal conserved segments and the X chromosomes. Intrachromosmal rearrangements and structural reorganization of the X chromosomes was likely accompanied by an accumulation, distribution, and evolution of repeated sequences.

Highlights

IntroductionMost eutherians have two sex chromosomes (gonosomes)—X and Y
Most eutherians have two sex chromosomes—X and Y
We performed C-banding of T. savii chromosomes and found a heterochromatic block in the p-arm of the X chromosome, which corresponded well to the location of this additional signal (Fig. 1b)

Summary

Introduction

Most eutherians have two sex chromosomes (gonosomes)—X and Y. One important conclusion was that the X chromosomes were often highly conserved even between distantly related species[3] This conservatism of the X chromosome even in phylogenetically distant mammals, such as humans, pigs, horses, dogs, and cats, was amply confirmed by the study of genetic marker o rder[4]. The X chromosomes of a significant number of mouse-like rodents (Myomorpha) and cetartiodactyls are clearly rearranged and subject to both intrachromosomal and interchromosomal rearrangements[11,12,13,14]. The mouse-like rodents have the highest number of species among mammals with rearranged sex c hromosomes[15]. It appears that sex chromosomes in these species are most often subject to translocation with autosomes and the Y chromosome is often lost. Some species exhibit hypervariability in the amount and distribution of heterochromatin (e.g. Lasiopodomys mandarinus[23])

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Discussion

Conclusion