Karyotype diversity suggests that Laonastes aenigmamus (Laotian rock rat) (Rodentia, Diatomyidae) is a multi-specific genus

Abstract

Laonastes aenigmamus (Khanyou) is a recently described rodent species living in geographically separated limestone formations of the Khammuan Province in Lao PDR. Chromosomes of 21 specimens of L. aenigmamus were studied using chromosome banding as well as fluorescent in situ hybridization (FISH) techniques using human painting, telomere repeats, and 28S rDNA probes. Four different karyotypes were established. Study with human chromosome paints and FISH revealed that four large chromosomes were formed by multiple common tandem fusions, with persistence of some interstitial telomeres. The rearrangements separating the different karyotypes (I to IV) were also reconstructed. Various combinations of Robertsonian translocations or tandem fusions involving the same chromosomes differentiate these karyotypes. These rearrangements create a strong gametic barrier, which isolates specimens with karyotype II from the others. C-banding and FISH with telomere repeats also exhibit large and systematized differences between karyotype II and others. These data indicate an ancient reproductive separation and suggest that Laonastes is not a mono-specific genus.

Karyotype analysis of Quasipaa spinosa David, 1875 (Anura, Dicroglossidae) with conventional cytogenetic techniques

“…These findings collectively indicate a prevalent occurrence of C-banding across species ( Kakampuy et al 2013 ). The BrdU -banding findings revealed that the BrdU -banding patterns of chromosomes 1–5 in both males and females was consistent with those reported by Richard et al (2016) , with the degree change in the BrdU -banding clearly observed in all of them. Additionally, the chromosomal BrdU -banding patterns for the three stages of the S-phase resembled those described by Schempp (1981), categorized as early, middle, and late.…”

High BrdU Sensitivity of Passeriformes Chromosomes: Conservation of BrdU-Sensitive Fragile Sites on Their Z Chromosomes during Evolution

“…Cell cultures, BrdU treatments, metaphase preparations, and chromosome banding were performed according to our standard protocols [Richard et al, 2016] except that BrdU treatments were extended from 4 to 18 h before harvesting. For co-cultures of G. gorilla (MNHN-TCCV-1074) and T. iliacus fibroblasts, the same number of cells from each species was grown for 6 h before synchronization by fluorodeoxyuridine.…”