Intrachromosomal Rearrangements in Rodents from the Perspective of Comparative Region-Specific Painting.

Svetlana A Romanenko,Natalya A Serdyukova,Alexander S Graphodatsky,Svetlana V Pavlova,Roscoe Stanyon,Feodor N Golenishchev,Nina S Bulatova,Polina L Perelman

doi:10.3390/genes8090215

Abstract

It has long been hypothesized that chromosomal rearrangements play a central role in different evolutionary processes, particularly in speciation and adaptation. Interchromosomal rearrangements have been extensively mapped using chromosome painting. However, intrachromosomal rearrangements have only been described using molecular cytogenetics in a limited number of mammals, including a few rodent species. This situation is unfortunate because intrachromosomal rearrangements are more abundant than interchromosomal rearrangements and probably contain essential phylogenomic information. Significant progress in the detection of intrachromosomal rearrangement is now possible, due to recent advances in molecular biology and bioinformatics. We investigated the level of intrachromosomal rearrangement in the Arvicolinae subfamily, a species-rich taxon characterized by very high rate of karyotype evolution. We made a set of region specific probes by microdissection for a single syntenic region represented by the p-arm of chromosome 1 of Alexandromys oeconomus, and hybridized the probes onto the chromosomes of four arvicolines (Microtus agrestis, Microtus arvalis, Myodes rutilus, and Dicrostonyx torquatus). These experiments allowed us to show the intrachromosomal rearrangements in the subfamily at a significantly higher level of resolution than previously described. We found a number of paracentric inversions in the karyotypes of M. agrestis and M. rutilus, as well as multiple inversions and a centromere shift in the karyotype of M. arvalis. We propose that during karyotype evolution, arvicolines underwent a significant number of complex intrachromosomal rearrangements that were not previously detected.

Highlights

Classical chromosome staining and banding allows some appreciation of the extent of chromosomal evolution across animal species
M. agrestis, M. arvalis, A. oeconomus, M. rutilus, and D. torquatus cell lines were retrieved from the IMCB SB RAS cell bank (“The general collection of cell cultures”, No 0310-2016-0002)
It was proposed that intrachromosomal rearrangements may be up to four times more frequent than other chromosomal rearrangements; chromosome painting—the most commonly used molecular cytogenetic method—leaves almost all inversions undetected [20,55]

Summary

Introduction

Classical chromosome staining and banding allows some appreciation of the extent of chromosomal evolution across animal species. Molecular cytogenetics puts karyological comparisons onto a more secure footing. Chromosome painting has allowed researchers to access, with a high degree of confidence, interchromosomal rearrangements that differentiate mammalian karyotypes. Genes 2017, 8, 215 over evolutionary time. Well over 100 species of mammals were studied with chromosomal painting. The method has mapped evolutionary conserved syntenic segments, fusions, and fissions over a wide phylogenetic array of species. These data were sufficient to make reasonable hypotheses on a fundamental goal of comparative cytogenetics—the reconstruction of ancestral karyotypes at principal phylogenetic nodes on the placental mammalian tree

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Discussion

Conclusion