The understanding of the evolution of variable sex determination mechanisms across taxa requires comparative studies among closely related species.
Following the fate of a known master sex-determining gene, we traced the evolution of sex determination in an entire teleost order Esociformes. We discovered that the northern pike Esox lucius master sex-determining gene originated from a 65 to 90 million-year-old gene duplication event and that it remained sex-linked on undifferentiated sex chromosomes for at least 56 million years in multiple species.
We identified several independent species- or population-specific sex determination transitions, including a recent loss of a Y-chromosome. These findings highlight the diversity of evolutionary fates of master sex-determining genes and the importance of population demographic history in sex determination studies. We hypothesize that occasional sex reversals and genetic bottlenecks provide a non-adaptive explanation for sex determination transitions.
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication. This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
Views, downloads and citations are aggregated across all versions of this paper published by eLife. The first complete 3D reconstruction of the compound eye of a minute wasp species sheds light on the nuts and bolts of size reduction. Seahorses, pipefishes, and seadragons are fishes from the family Syngnathidae that have evolved extraordinary traits including male pregnancy, elongated snouts, loss of teeth, and dermal bony armor.
