TY - JOUR

T1 - Against the Odds

T2 - Hybrid Zones between Mangrove Killifish Species with Different Mating Systems

AU - Berbel-Filho, Waldir M.

AU - Tatarenkov, Andrey

AU - Pacheco, George

AU - Espírito-Santo, Helder M. V.

AU - Lira, Mateus G.

AU - de Leaniz, Carlos Garcia

AU - Avise, John C.

AU - Lima, Sergio M. Q.

AU - Rodríguez-López, Carlos M.

AU - Consuegra, Sofia

N1 - Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

PY - 2021

Y1 - 2021

N2 - Different mating systems are expected to affect the extent and direction of hybridization. Due to the different levels of sexual conflict, the weak inbreeder/strong outbreeder (WISO) hypothesis predicts that gametes from self-incompatible (SI) species should outcompete gametes from selfcompatible (SC) ones. However, other factors such as timing of selfing and unilateral incompatibilities may also play a role on the direction of hybridization. In addition, differential mating opportunities provided by different mating systems are also expected to affect the direction of introgression in hybrid zones involving outcrossers and selfers. Here, we explored these hypotheses with a unique case of recent hybridization between two mangrove killifish species with different mating systems, Kryptolebias ocellatus (obligately outcrossing) and K. hermaphroditus (predominantly selffertilizing) in two hybrid zones in southeast Brazil. Hybridization rates were relatively high (~20%), representing the first example of natural hybridization between species with different mating systems in vertebrates. All F1 individuals were sired by the selfing species. Backcrossing was small, but mostly asymmetrical with the SI parental species, suggesting pattern commonly observed in plant hybrid zones with different mating systems. Our findings shed light on how contrasting mating systems may affect the direction and extent of gene flow between sympatric species, ultimately affecting the evolution and maintenance of hybrid zones.

AB - Different mating systems are expected to affect the extent and direction of hybridization. Due to the different levels of sexual conflict, the weak inbreeder/strong outbreeder (WISO) hypothesis predicts that gametes from self-incompatible (SI) species should outcompete gametes from selfcompatible (SC) ones. However, other factors such as timing of selfing and unilateral incompatibilities may also play a role on the direction of hybridization. In addition, differential mating opportunities provided by different mating systems are also expected to affect the direction of introgression in hybrid zones involving outcrossers and selfers. Here, we explored these hypotheses with a unique case of recent hybridization between two mangrove killifish species with different mating systems, Kryptolebias ocellatus (obligately outcrossing) and K. hermaphroditus (predominantly selffertilizing) in two hybrid zones in southeast Brazil. Hybridization rates were relatively high (~20%), representing the first example of natural hybridization between species with different mating systems in vertebrates. All F1 individuals were sired by the selfing species. Backcrossing was small, but mostly asymmetrical with the SI parental species, suggesting pattern commonly observed in plant hybrid zones with different mating systems. Our findings shed light on how contrasting mating systems may affect the direction and extent of gene flow between sympatric species, ultimately affecting the evolution and maintenance of hybrid zones.

KW - Asymmetric introgression

KW - Kryptolebias

KW - Mixed mating

KW - Reproductive isolation

KW - Selffertilization

U2 - 10.3390/genes12101486

DO - 10.3390/genes12101486

M3 - Journal article

C2 - 34680881

AN - SCOPUS:85116006754

VL - 12

JO - Genes

JF - Genes

SN - 2073-4425

IS - 10

M1 - 1486

ER -