Exploring the genetic basis and evolution of Pantherine historical inter-specific hybridization

CAMPOS, MARÍA CLARA; PENNA, CLEMENTINA; FRANCISCO PISCIOTTANO; SARAGÜETA, PATRICIA

Congreso; XI-CAB2C; 2021

Exploring the genetic basis and evolution of Pantherine historical inter-specific hybridizationBackground:Genomic introgression analysis exposed a complex pattern of historical inter-specific hybridization in the Pantherinae lineage. This findings revealed unusually high rates of fertilization among pantherines, particularly between Panthera leo and Panthera onca, that would indicate an absence of inter-specific isolation barriers.Zona Pellucida (ZP) and Juno (IZUMO1R) oocyte proteins play a key role in mammalian fertilization process, facilitating the interaction and fusion between the oocyte and the sperm respectively. Specifically ZP2 and ZP3 are directly involved in the interaction between gametes, ZP1 and ZP4 play the role of crosslinkers. Their interaction with sperm counterparts is essential for gamete interaction and the lack of recognition between them can constitute a pre-cigotic reproductive isolation mechanism. Hi-C long-range sequencing and chromosome-resolved genome assembly was used to reconstruct the intricate phylogeny of gamete interaction proteins to uncover the underlying molecular basis of inter-species crossing and evolution of the functional capacities of pantherinesResults:In this work we explored the evolutionary patterns of ZP1, ZP2, ZP3, ZP4 and Juno proteins in the pantherines as well as in Feliformia and Caniformia suborders and the whole Carnivora order detecting adaptive changes, pairwise sequence identity and similarity analysis and evolutionary relevant sites based on curated multiple sequence alignments.The conservation of all carnivora gamete interaction proteins was significantly higher (p-value < 0.05) in feliformes compared to caniformes except for the case of ZP4. ZP3 and ZP2 proteins displayed a similar pattern of evolution along their phylogenies showing adaptive changes in caniformes subtree but not among felid species. On the other hand, both ZP1 and ZP4 display a different evolutionary history, showing signatures of positive selection inside felids subtree. The fusion protein IZUMO1R did not show positive selection among all studied phylogenetic groupsConclusions:These results strengthen the idea that ZPs are proteins that provide a more specific-specificity isolation than IZUMO1R, which is specialized in fusion events. Altogether, our findings indicate that sperm-oocyte interaction and fusion proteins lack the degree of diversification necessary to fix a prezygotic reproductive isolation barrier in felidae.