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Abstract

Species of the subgenus Neritrema (genus Littorina) represent a model to study
speciation. Although many aspects of littorinid morphology, ecology and physiology are well known, mechanism of interspecific reproductive isolation are not yet clear: behavioral barriers and postzygotic constrains are described, but nothing is known about gamete incompatibility. Studies of such model organisms as sea urchins, Haliotis molluscs and fruit flies showed that variability of reproductive proteins may play key role for reproductive isolation. That is why our research is focused on reproductive proteins and their variability in periwinkles. Earlier we identified a novel protein in L. obtusata sperm (LOSP), highly specific for male reproductive system. Here we demonstrate that mature LOSP is localized out of spermatozoa using two different approaches (immunohystochemistry and in situ hybridization). Most probably it is one
of the seminal fluid components. The protein is produced by specialized cells in male gonad (there is no LOSP-positive cells in seminal vesicles) which release LOSP into gonad¿s lumen via exocytosis. Our results imply that there is an orthologous gene in L. fabalis. Considering positive BLAST-search results in raw transcriptomic and genomic data of L. saxatilis, obtained by our colleagues (unpublished), it is reasonable to predict the existence of homologous protein in other littorinids. In both L. fabalis and L. saxatilis losp is intronless so most probably it is an ancestral feature. The degree of coding sequence variability between L. obtusata and L. fabalis was very limited, but there were robust differences between L. saxatilis and L. obtusata/L. fabalis. Thus, in L. obtusata/L. fabalis LOSP seems to be conservative, unlike it¿s L. saxatilis homologue. Seminal proteins may be important for reproductive isolation in the species with internal fertilization and polyandry. In such species seminal fluid proteins may influence to sperm storage or conspecific sperm precedence.
Translated title of the contributionРепродуктивные белки Литторин: что нового?
Original languageEnglish
Pages8-9
Number of pages45
Publication statusPublished - 13 Aug 2017

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