The research program

Sex chromosomes arise from ordinary autosomes, recombination halts between them, and once that happens the Y (or W) begins to degenerate. We use comparative cytogenetics, dosage-compensation data, and population-genetic theory to ask how sexually antagonistic selection, genetic drift, and dosage tolerance shape that trajectory across animals.

Birds were long treated as the textbook case of chromosomal stasis. Our 2026 preprint shows they sit above the global median once microchromosome dynamics are resolved, and that rates of dysploidy vary 844-fold across eukaryotes. The predictors that come out on top are about life history, not taxonomic group.

Across large samples the distribution of chromosome numbers is not flat. We ask whether the modes we observe reflect genuine optima (set by recombination, meiotic stability, or genome size) or simply historical contingency, and how that answer changes with life history.

Rearrangements that pull autosomal material into the sex-linked region can be favored or purged depending on the selection acting on loci they capture. We model this explicitly with population-genetic simulations and test predictions against empirical data from beetles and other animals with unusually rich sex chromosome diversity.

This is the classical question of sexual antagonism, asked with modern data. We use behavioral, morphological, and genomic measurements across systems (Betta, beetles, mammals) to ask when the same allele is good for both sexes and when it isn't.

We re-analyzed over 1,600 line-cross datasets with the SAGA information-theoretic framework we built for this kind of work. Epistasis shows up in the majority of crosses, and its frequency differs between plants and animals in ways that matter for how we predict response to selection.

Domesticated systems (tomatoes, chickens, Betta) are rapid, replicated natural experiments in adaptation. We use them to ask questions about the genetic architecture of quantitative traits, the repeatability of evolution under strong selection, and how radiation unfolds once a population escapes the constraints that held its wild relatives in place.

In practice this looks like forward population-genetic simulations in our own R code or in SLiM, paired with analytical treatments when they are tractable. We use theory to generate null expectations for chromosomal rearrangements, sexually antagonistic alleles, and dysploidy rates, so that our comparative tests have something sharp to push against.

Most of our published work pulls trait data onto a phylogeny and asks where, when, and how fast something changed. We maintain an R package ecosystem (evobiR and related tools) for this kind of analysis, teach the methods to undergraduates in the CURE, and write guides for the rest of the community.

When the question needs data we can't get from the literature we generate it ourselves. That means tomato and Betta crosses, chromosome preparations from beetles, short-read sequencing, and the bioinformatic pipelines (mapping, variant calling, QTL analysis) that turn raw reads into trait and genotype matrices ready for comparative work.

Beetles are the group around which a lot of the chromosomal work is built. They display more sex chromosome systems than any other animal order and cover an enormous range of chromosome numbers, so they are our go-to clade for comparative questions about karyotype evolution and sex chromosomes.

Solanum crosses give us a tractable plant system for quantitative genetics, epistasis, and the genetic architecture of morphological traits. Domestication gives us a rapid, replicated experiment in adaptation we can study at the molecular level.

Betta splendens are tractable in the lab, display strong sexual dimorphism, and have been under intense artificial selection for aggression and ornamentation for centuries. They are a natural system for asking questions about sexual antagonism and the genetic basis of behavior.

Chickens anchor our vertebrate work on sex chromosome evolution (they use a Z/W system) and let us do direct comparisons with the X/Y lineages we work on in mammals and beetles. The depth of published chicken genomics is a real asset for comparative pipelines.

Brachyuran crabs have moved from saltwater to freshwater independently in multiple lineages. We use that replication to ask about the comparative genomics of habitat transitions and to test whether karyotype evolution tracks ecological transitions in this group.

Mammals give us the classic X/Y sex chromosome system at large scale and a wealth of existing genomic and cytogenetic data. Our Carnivora work (range size versus karyotype evolution rate) draws directly on this group, and the comparisons with Coleoptera are where some of our strongest results come from.