The rise and fall of the ancient northern pike master sex-determining gene
Qiaowei Pan, Romain Feron, Elodie Jouanno, Hugo Darras, Amaury Herpin, Ben F. Koop, Eric B. Rondeau, Frederick W. Goetz, Wesley A. Larson, Louis Bernatchez, Mike Tringali, Stephen S. Curran, Eric Saillant, Gaël P.J. Denys, Frank A. von Hippel, Songlin Chen, J. Andrés López, Hugo Verreycken, Konrad Ocalewicz, René Guyomard, Camille Eché, Jérôme Lluch, Céline Lopez‐Roques, Hongxia Hu, Roger A. Tabor, Patrick W. DeHaan, Krista M. Nichols, Laurent Journot, Hugues Parrinello, Christophe Klopp, Е. А. Интересова, Vladimir A. Trifonov, Manfred Schartl, John H. Postlethwait, Yann Guiguen
Abstract
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.