A comparative study on karyotypic diversification rate in mammals

Abstract

Chromosomal rearrangements have a relevant role in organismic evolution. However, little is known about the mechanisms that lead different phylogenetic clades to have different chromosomal rearrangement rates. Here, we investigate the causes behind the wide karyotypic diversity exhibited by mammals. In particular, we analyzed the role of metabolic, reproductive, biogeographic and genomic characteristics on the rates of macro- and microstructural karyotypic diversification (rKD) using comparative phylogenetic methods. We found evidence that reproductive characteristics such as larger litter size per year and longevity, by allowing a higher number of meioses in absolute time, favor a higher probability of chromosomal change. Furthermore, families with large geographic distributions but containing species with restricted geographic ranges showed a greater probability of fixation of macrostructural chromosomal changes in different geographic areas. Finally, rKD does not evolve by Brownian motion because the mutation rate depends on the concerted evolution of repetitive sequences. The decisive factors of rKD evolution will be natural selection, genetic drift and meiotic drive that will eventually allow or not the fixation of the rearrangements. Our results indicate that mammalian karyotypic diversity is influenced by historical and adaptive mechanisms where reproductive and genomic factors modulate the rate of chromosomal change.

Genome size variation and species diversity in salamanders

“…Together, our analyses support the Geographic Range Hypothesis, according to which taxa with wider geographic distributions have higher probabilities that genetic changes such as indels, chromosomal inversions and transposon-mediated modifications in genome size will become fixed in a population (Feder, Gejji, Powell, & Nosil, 2011;Hooper & Price, 2015;Leaché, Banbury, Linkem, & de Oca, 2016;Martinez et al, 2017). If habitat and niche availability both increase with geographic area, then our observations suggest that changes in genome size in urodeles might have occurred in parallel with adaptations that made available habitats and niches more accessible to dispersing ancestral populations, but only over longer evolutionary periods (family-level clades relative to genus-level clades in the same lineage).…”

Meiotic drive shapes rates of karyotype evolution in mammals

“…; Martinez et al. ) in large‐scale karyotype evolution should allow for the possible impact of meiotic drive.…”

“…Our findings suggest that meiotic drive may be a widespread force in shaping chromosome number evolution. The striking difference in rates of chromosome number evolution between taxa with matched and mismatched karyotypes suggests that any attempts to identify the role of alternative forces like population structure or selection (Bengtsson 1980;Petitpierre 1987;Martinez et al 2015;Ross et al 2015;Martinez et al 2016) in largescale karyotype evolution should allow for the possible impact of meiotic drive. Many theoretical models have invoked chromosomal evolution as a driver of speciation.…”

Spatial and temporal divergence of the torquatus species group of the subterranean rodent Ctenomys

“…We took into account chromosomal rearrangements that modify diploid and/or fundamental numbers caused by Robertsonian fusions/fissions and/or pericentric inversions. To do so, we defined the macrostructural karyotypic diversification (mKD) within a lineage as the number of different karyomorphs following Martínez et al (2016). Microstructural rearrangements require chromosome banding and/or painting techniques to be detected, but these studies are not complete for all members of the torquatus group.…”