Ecology and the evolution of sex chromosomes

Abstract

Work on the evolution of sex chromosomes and sex determination in the Meisel lab is supported by the National Science Foundation under Grant No. DEB-1845686.

Evolution and expression patterns of the neo-sex chromosomes of the crested ibis

“…In terms of chromosome evolution, this is reflected in the suppressed recombination between sex chromosomes 1 . The non-recombing regions of the W chromosome are severely degenerated due to increased sexual antagonism and the low efficiency of natural selection, resulting from Muller's ratchet and the Hill-Robertson effect 5,15,78 . In bird species with female heterogamety (ZW system), sexual dimorphism and maletargeted sexual selection 79,80 led to the excess accumulation of male fitness mutations on the Z chromosome, promoting a faster evolutionary rate for the Z chromosome, which is known as the 'fast-Z' effect 81,82 .…”

“…In most birds and mammals, sex is determined by a pair of heteromorphic sex chromosomes (Z-W in birds and X-Y in mammals) that differ in morphology, size, and gene content 3,4 . In most birds and mammals, the Z and X chromosomes, respectively, are evolutionarily conserved, with relatively stable structures and gene contents 5,6 , while the sexlimited W and Y chromosomes exhibit a high degree of heterochromatinization and typically contain only a few genes due to the lack of recombination 2,[7][8][9] .…”

Turnover of multiple sex chromosomes in Harttia catfish (Siluriformes, Loricariidae): a glimpse from whole chromosome painting

“…Structuring into small, geographically isolated populations may also facilitate sex chromosome differentiation and transition between sex chromosome systems (e.g., Primo et al, 2017;Cioffi et al, 2018;Krysanov & Demidova, 2018;Glugoski et al, 2020;Štundlová et al, 2022;Marajó et al, 2023) To answer the question whether indeed genetic drift is a major force in sex chromosomes fixation in Harttia and other fish lineages with similar eco-geographical and demographic features and whether certain selective forces and ecological factors (cf. Pennell et al, 2015;Veller et al, 2017;Saunders et al, 2018;Meisel, 2022) might have played a role in this process, we have to acquire much deeper knowledge especially concerning genetic content and degree of sex chromosome differentiation, presence/absence of sex chromosomes in wide range of conspecific populations, and their phylogenetic distribution based on well-resolved phylogeny (cf. Sember et al, 2021).…”

Sex chromosome evolution: The remarkable diversity in the evolutionary rates and mechanisms

“…Are there more factors contributing to the process of sex chromosome differentiation? Meisel (2022) argues that sex-specific selection in different habitats caused by sex-specific vulnerability to different environmental factors or pathogens, could lead to niche partitioning or different dietary strategies between sexes, which might affect the dynamics of sex chromosome evolution. The author goes on to suggest that the evolution of sex determination can be affected by ecological factors, especially in species where the sex determination pathway is sensitive to temperature, such as in some reptiles, teleost fishes and other vertebrates.…”

“…Future work should focus on identifying the underlying forces and genetic mechanisms driving sex chromosome turnovers. In addition, it should also focus on the importance of ecologically relevant selection pressure in sex chromosome turnovers (Meisel, 2022). Identifying how and what makes the sex-determining mechanisms so labile in certain lineages, but very stable in others, is still a challenge.…”