New reprint: Hoisted with his own petard: how sex-ratio meiotic drive in Drosophila affinis creates resistance alleles that limit its spread

What is the evolution, dynamics of meiotic drive and the Y-chromosome nondisjunction? Do they lead to Y chromosome loss and thus sex chromosome turnover?

Great teamwork from our fabulous lab technician Kistie Brunsell, undergraduates Emma Knoles and Murtaza Shoaib.




Figure 1. An overview of SR meiotic drive and nondisjunction rate in males in D. affinis.




Figure 2. Lower cost of XSR in females leads to oscillating allele frequencies. A) Representative trajectories for XSR and O with homozygous cost of XSR ranging from 0.1 to 0.9 (1000 generations displayed), B) The same data with ferquencies of XSR in females and O in males plotted on the Y and X axis, respectively (10,000 generations displayed). Read More…

Glad to share the recent work:

The Diversity and Evolution of Sex Chromosomes in Frogs

https://doi.org/10.3390/genes12040483

Frogs are ideal organisms for studying sex chromosome evolution because of their diversity in sex chromosome differentiation and sex-determination systems. We review 222 anuran frogs, spanning ~220 Myr of divergence, with characterized sex chromosomes, and discuss their evolution, phylogenetic distribution and transitions between homomorphic and heteromorphic states, as well as between sex-determination systems. Most (~75%) anurans have homomorphic sex chromosomes, with XY systems being three times more common than ZW systems. Most remaining anurans (~25%) have heteromorphic sex chromosomes, with XY and ZW systems almost equally represented. There are Y-autosome fusions in 11 species, and no W-/Z-/X-autosome fusions are known. The phylogeny represents at least 19 transitions between sex-determination systems and at least 16 cases of independent evolution of heteromorphic sex chromosomes from homomorphy, the likely ancestral state. Five lineages mostly have heteromorphic sex chromosomes, which might have evolved due to demographic and sexual selection attributes of those lineages. Males do not recombine over most of their genome, regardless of which is the heterogametic sex. Nevertheless, telomere-restricted recombination between ZW chromosomes has evolved at least once. More comparative genomic studies are needed to understand the evolutionary trajectories of sex chromosomes among frog lineages, especially in the ZW systems.

Read More…

Thrilled to see this work is finally out in Molecular Ecology!

A single QTL with large effect is associated with female functional virginity in an asexual parasitoid wasp

https://doi.org/10.1111/mec.15863

During the transition from sexual to asexual reproduction, a suite of reproduction‐related sexual traits become superfluous, and may be selected against if costly. Female functional virginity refers to asexual females resisting to mate or not fertilizing eggs after mating. These traits appear to be among the first that evolve during transitions from sexual to asexual reproduction. The genetic basis of female functional virginity remains elusive. Previously, we reported that female functional virginity segregates as expected for a single recessive locus in the asexual parasitoid wasp Asobara japonica. Here, we investigate the genetic basis of this trait by quantitative trait loci (QTL) mapping and candidate gene analyses. Consistent with the segregation of phenotypes, we found a single QTL of large effect, spanning over 4.23 Mb and comprising at least 131 protein‐coding genes, of which 15 featured sex‐biased expression in the related sexual species Asobara tabida. Two of the 15 sex‐biased genes were previously identified to differ between related sexual and asexual population/species: CD151 antigen and nuclear pore complex protein Nup50. A third gene, hormone receptor 4, is involved in steroid hormone mediated mating behaviour. Overall, our results are consistent with a single locus, or a cluster of closely linked loci, underlying rapid evolution of female functional virginity in the transition to asexuality. Once this variant, causing rejection to mate, has swept through a population, the flanking region does not get smaller owing to lack of recombination in asexuals.

Read More…

Thrilled to share my last unpublished PhD work

A single QTL with large effect is associated with female functional virginity in an asexual parasitoid wasp

In this study, we investigate the genomic regions underpinning female functional virginity by QTL mapping and candidate gene analyses. Consistent with the segregation of phenotypes, our QTL analysis identified a single large-effect size QTL on LG12 at 7 or 8 cM, strongly associated with female functional virginity.

To our knowledge, this is the first study to identify candidate genes for female functional virginity, a trait that is predicted to evolve in transition from sexuality to asexuality. Overall, our results are consistent with a single gene or a cluster of linked genes underlying rapid evolution of female functional virginity in the transition to asexuality. Once a mutation for rejection to mate has swept through a population, the region comprising the gene(s) does not get smaller due to lack of recombination in asexuals.

More details and results about this article can be found here.

Read More…