My biological interests stem from an evolutionary puzzle: why does sex exist? In theory, a lineage of asexual females can reproduce twice as efficiently as a competing sexual population, whose resources are diverted into males that cannot produce eggs. Why does natural selection maintain sex so widely despite this and other costs, and why do most asexual lineages rapidly go extinct? To address these questions, I study a group of animals that have succeeded despite lacking males. Bdelloid rotifers are microscopic invertebrates that live in almost every pond, stream, puddle and patch of moss in the world. Hundreds of species have been described and thousands of individuals examined, but all of them so far have been female, and reproduction is known only via asexual eggs.
My collaborators and I apply genetic and ecological principles to investigate the causes and consequences of the unusual reproductive system of bdelloid rotifers. I am especially interested in how bdelloids deal with the rapidly changing selection imposed by infectious disease, and have studied their interactions with pathogens across several scales, from individuals to populations and species. We use approaches ranging from long-term field studies and experimental evolution to population genetics, comparative genomics, metagenomics and transcriptomics. In 2024, this work revealed that bdelloid rotifers have spent millions of years acquiring antimicrobial synthesis genes from microbes to deploy against their own fungal pathogens — a defensive strategy previously unknown in animals.
We are now taking this discovery forward through the Oxford Martin Programme on Safer Antifungals, where I help lead the translation of rotifer research into a technology with real-world applications. This interdisciplinary programme brings together evolutionary and fungal biology, biochemistry, pharmacology and machine learning to investigate whether the unusual defensive strategies of rotifers might offer a new route to discovering safer antifungal chemistry, with an initial focus on crop protection. I work with colleagues at Oxford University Innovation, the Saïd Business School and in Oxford's wider innovation and venture community to explore how technologies emerging from fundamental biology can transition toward sustainable commercial development or industry partnership.
I also teach biology at undergraduate and graduate level, with a focus on evolution, genomics, host–pathogen interactions and the evolutionary consequences of sex and asexuality.
BarraLab
