The Molecular Mechanisms of Gametic Incompatibility in Invertebrates

Abstract

Fertilization (gamete fusion followed by zygote formation) is a multistage process. Each stage is mediated by ligand-receptor recognition of gamete interaction molecules. This recognition includes the movement of sperm in the gradient of egg chemoattractants, destruction of the egg envelope by acrosomal proteins, etc. Gametic incompatibility is one of the mechanisms of reproductive isolation. It is based on species-specific molecular interactions that prevent heterospecific fertilization. Although gametic incompatibility may occur in any sexually reproducing organism, it has been studied only in a few model species. Gamete interactions in different taxa involve generally similar processes, but they often employ non-homologous molecules. Gamete recognition proteins evolve rapidly, like immunity proteins, and include many taxon-specific families. In fact, recently appeared proteins particularly contribute to reproductive isolation via gametic incompatibility. Thus, we can assume a multiple, independent origin of this type of reproductive isolation throughout animal evolution. Gametic incompatibility can be achieved at any fertilization stage and entails different consequences at different taxonomic levels and ranges, from complete incompatibility between closely related species to partial incompatibility between distantly related taxa.

Proteins of penial mamilliform glands in closely related <em>Littorina</em> species (Mollusca, Caenogastropoda): variability and possible contribution to reproductive isolation

“…Penises were dissected and divided into two parts: mamilliform glands and basal fragments (SM 1). Each piece of tissue was collected into lysis buffer and homogenized (Maltseva et al, 2016).…”

“…Statistical analysis Spot identification for 2D electrophoresis analysis was done in PDQuest (BioRad) software. The final dataset was analyzed in R (R Core Team, 2019; Maltseva et al, 2016).…”

“…LC-MS/MS Differentially expressed proteins were excised from the Coomassie stained gels and identified by HPLC-tandem-mass-spectrometry (Agilent 6538, Agilent Technologies) following the "bottom up" approach as described earlier (Maltseva et al, 2016). MS/ MS search was done using Agilent Spectrum Mill MS Proteomics Workbench (Agilent Technologies; Rev B.…”

“…However, basal fragmentspecific proteins f_1-f_5 ( Fig. 1, a -green arrows with dots; SM 4) were previously detected as both speciesand penis-specific (in comparison to other body parts); mamilliform glands were proposed as the site of their production (Maltseva et al, 2016). Here we confirmed the specificity of f_1-f_5 for the L. saxatilis and L. arcana species pair, but disproved their origin from mamilliform glands; instead, they are expressed in the basal part of the penis.…”

“…arcana Hannaford Ellis 1978, L. compressa Jeffreys 1865 and "obtusata" (L. obtusata (Linnaeus 1758), L. fabalis (Turton 1825)); all of these sympatrically inhabit the European North Atlantic sea shores (Yashenko and Granovitch, 2002;Granovitch et al, 2004). Physiological consequences of local ecological and evolutionary adaptation can be traced in particular species and subpopulations of these molluscs (Sokolova et al, 2000(Sokolova et al, , 2001; Panova and Johannesson, 2004;Rolán-Alvarez et al, 2015;Maltseva et al, 2016). This suggests the importance of ecological sympatric speciation in the evolutionary history of this species group (Johannesson, 2003;Grahame et al, 2006;Rolán-Alvarez et al, 2007.…”