%0 Journal Article
%T Genetic sex determination in three closely related hydrothermal vent gastropods, including one species with intersex individuals.
%A Castel J
%A Pradillon F
%A Cueff V
%A Leger G
%A Daguin-Thiébaut C
%A Ruault S
%A Mary J
%A Hourdez S
%A Jollivet D
%A Broquet T
%J J Evol Biol
%V 37
%N 7
%D 2024 Jul 10
%M 38699972
%F 2.516
%R 10.1093/jeb/voae051
%X Molluscs have undergone many transitions between separate sexes and hermaphroditism, which is of interest in studying the evolution of sex determination and differentiation. Here, we combined multi-locus genotypes obtained from restriction site-associated DNA (RAD) sequencing with anatomical observations of the gonads of three deep-sea hydrothermal vent gastropods of the genus Alviniconcha living in the southwest Pacific. We found that all three species (Alviniconcha boucheti, Alviniconcha strummeri, and Alviniconcha kojimai) share the same male-heterogametic XY sex-determination system but that the gonads of XX A. kojimai individuals are invaded by a variable proportion of male reproductive tissue. The identification of Y-specific RAD loci (found only in A. boucheti) and the phylogenetic analysis of three sex-linked loci shared by all species suggested that X-Y recombination has evolved differently within each species. This situation of three species showing variation in gonadal development around a common sex-determination system provides new insights into the reproductive mode of poorly known deep-sea species and opens up an opportunity to study the evolution of recombination suppression on sex chromosomes and its association with mixed or transitory sexual systems.