Postmating/Prezygotic Isolation, Heterosis, and Outbreeding Depression in Crosses Within and Between Populations of Diodia teres (Rubiaceae) Walt.

2009 ◽  
Vol 170 (3) ◽  
pp. 301-310 ◽  
Author(s):  
Joe Hereford
Keyword(s):  
Outbreeding Depression ◽  
Prezygotic Isolation ◽  
Postmating Prezygotic Isolation

scholarly journals Conflict over fertilization underlies the transient evolution of reinforcement

2020 ◽  
Author(s):  
Catherine A. Rushworth ◽  
Alison M. Wardlaw ◽  
Jeffrey Ross-Ibarra ◽  
Yaniv Brandvain
Keyword(s):  
Genetic Model ◽  
Male Gamete ◽  
Coordination Problem ◽  
Potential Conflict ◽  
Prezygotic Isolation ◽  
Male Gametes ◽  
Geographic Patterns ◽  
The Face ◽  
Postmating Prezygotic Isolation ◽  
Two Populations

ABSTRACTWhen two populations or species hybridize, their offspring often experience reductions in fitness relative to either parental population. The production of low fitness hybrids may be prevented by the evolution of increased prezygotic isolation; a process known as reinforcement. Theoretical challenges to the evolution of reinforcement are generally cast as a coordination problem — e.g., linkage disequilibrium between trait and preference loci is difficult to maintain in the face of recombination. However, the evolution of reinforcement also poses a potential conflict between mates. For example, the opportunity costs to hybridization may differ between the sexes or species. This is particularly likely for postmating prezygotic isolation, as the ability to fertilize both conspecific and heterospecific eggs is beneficial to male gametes, but heterospecific mating may incur a cost for female gametes. Motivated by this problem, we develop a population genetic model of interspecific conflict over reinforcement, inspired by ‘gametophytic factors’, which act as postmating prezygotic barriers among Zea mays subspecies. We demonstrate that this conflict results in the transient evolution of reinforcement – after female preference for a conspecific gamete trait rises to high frequency, male traits adaptively introgress into the other population. Ultimately the male gamete trait fixes in both species, and prezygotic isolation returns to pre-reinforcement levels. We interpret geographic patterns of isolation among Z. mays subspecies in light of these findings, and suggest when and how this conflict can be mediated. Our results suggest that sexual conflict may pose an understudied obstacle to the evolution of reinforcement via postmating prezygotic isolation.

scholarly journals Sorted gene genealogies and species-specific nonsynonymous substitutions point to putative postmating prezygotic isolation genes inAllonemobiuscrickets

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1678 ◽  
Author(s):  
Suegene Noh ◽  
Jeremy L. Marshall
Keyword(s):  
Contact Zone ◽  
Arginine Kinase ◽  
Gene Trees ◽  
Lineage Sorting ◽  
Protein Coding ◽  
Advanced Degrees ◽  
Prezygotic Isolation ◽  
Species Specific ◽  
Allonemobius Socius ◽  
Postmating Prezygotic Isolation

In theAllonemobius sociuscomplex of crickets, reproductive isolation is primarily accomplished via postmating prezygotic barriers. We tested seven protein-coding genes expressed in the male ejaculate for patterns of evolution consistent with a putative role as postmating prezygotic isolation genes.Our recently diverged species generally lacked sequence variation. As a result,ω-based tests were only mildly successful. Some of our genes showed evidence of elevatedωvalues on the internal branches of gene trees. In a couple genes these internal branches coincided with both species branching events of the species tree, betweenA. fasciatusand the other two species, and betweenA. sociusandA. sp. nov.Tex. In comparison, more successful approaches were those that took advantage of the varying degrees of lineage sorting and allele sharing among our young species. These approaches were particularly powerful within the contact zone. Among the genes we tested we found genes with genealogies that indicated relatively advanced degrees of lineage sorting across both allopatric and contact zone alleles. Within a contact zone between two members of the species complex, only a subset of genes maintained allelic segregation despite evidence of ongoing gene flow in other genes. The overlap in these analyses wasarginine kinase(AK) andapolipoprotein A-1 binding protein(APBP). These genes represent two of the first examples of sperm maturation, capacitation, and motility proteins with fixed non-synonymous substitutions between species-specific alleles that may lead to postmating prezygotic isolation. Both genes express ejaculate proteins transferred to females during copulation and were previously identified through comparative proteomics. We discuss the potential function of these genes in the context of the specific postmating prezygotic isolation phenotype among our species, namely conspecific sperm precedence and the superior ability of conspecific males to induce oviposition in females.

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