scholarly journals A mitochondrial genetic divergence proxy predicts the reproductive compatibility of mammalian hybrids

2020 ◽  
Vol 287 (1928) ◽  
pp. 20200690 ◽  
Author(s):  
Richard Allen ◽  
Hannah Ryan ◽  
Brian W. Davis ◽  
Charlotte King ◽  
Laurent Frantz ◽  
...  

Numerous pairs of evolutionarily divergent mammalian species have been shown to produce hybrid offspring. In some cases, F 1 hybrids are able to produce F 2 s through matings with F 1 s. In other instances, the hybrids are only able to produce offspring themselves through backcrosses with a parent species owing to unisexual sterility (Haldane's Rule). Here, we explicitly tested whether genetic distance, computed from mitochondrial and nuclear genes, can be used as a proxy to predict the relative fertility of the hybrid offspring resulting from matings between species of terrestrial mammals. We assessed the proxy's predictive power using a well-characterized felid hybrid system, and applied it to modern and ancient hominins. Our results revealed a small overlap in mitochondrial genetic distance values that distinguish species pairs whose calculated distances fall within two categories: those whose hybrid offspring follow Haldane's Rule, and those whose hybrid F 1 offspring can produce F 2 s. The strong correlation between genetic distance and hybrid fertility demonstrated here suggests that this proxy can be employed to predict whether the hybrid offspring of two mammalian species will follow Haldane's Rule.

2020 ◽  
Author(s):  
Emily E. Bendall ◽  
Kayla M. Mattingly ◽  
Amanda J. Moehring ◽  
Catherine R. Linnen

AbstractEvolutionary biologists have long been interested in understanding the mechanisms underlying Haldane’s rule. The explanatory theories of dominance and faster-X, which are based on recessive alleles being expressed in the heterogametic sex, have been proposed as common mechanisms. These mechanisms predict that greater hemizygosity leads to both faster evolution and greater expression of intrinsic postzygotic isolation. Under these mechanisms, haplodiploids should evolve and express intrinsic postzygotic isolation faster than diploids because the entire genome is analogous to a sex chromosome. Here, we measure sterility and inviability in hybrids between Neodiprion pinetum and N. lecontei, a pair of haplodiplopids that differ morphologically, behaviorally, and genetically. We compare the observed isolation to that expected from published estimates of isolation in diploids at comparable levels of genetic divergence. We find that both male and female hybrids are viable and fertile, which is less isolation than expected. We then discuss several potential explanations for this surprising lack of isolation, including alternative mechanisms for Haldane’s rule and a frequently overlooked quirk of haplodiploid genetics that may slow the emergence of complete intrinsic postzygotic isolation in hybrid males. Finally, we describe how haplodiploids, an underutilized resource, can be used to differentiate between mechanisms of Haldane’s rule.


Genetics ◽  
1996 ◽  
Vol 143 (1) ◽  
pp. 603-607
Author(s):  
Ling-Wen Zeng

Evolution ◽  
2005 ◽  
Vol 59 (5) ◽  
pp. 1016-1026 ◽  
Author(s):  
Michel Slotman ◽  
Alessandra Della Torre ◽  
Jeffrey R. Powell

2013 ◽  
Vol 9 (5) ◽  
pp. 20130327 ◽  
Author(s):  
Matthew Schrader ◽  
Rebecca C. Fuller ◽  
Joseph Travis

Crosses between populations or species often display an asymmetry in the fitness of reciprocal F 1 hybrids. This pattern, referred to as isolation asymmetry or Darwin's Corollary to Haldane's Rule, has been observed in taxa from plants to vertebrates, yet we still know little about which factors determine its magnitude and direction. Here, we show that differences in offspring size predict the direction of isolation asymmetry observed in crosses between populations of a placental fish, Heterandria formosa . In crosses between populations with differences in offspring size, high rates of hybrid inviability occur only when the mother is from a population characterized by small offspring. Crosses between populations that display similarly sized offspring, whether large or small, do not result in high levels of hybrid inviability in either direction. We suggest this asymmetric pattern of reproductive isolation is due to a disruption of parent–offspring coadaptation that emerges from selection for differently sized offspring in different populations.


Genetics ◽  
1993 ◽  
Vol 133 (2) ◽  
pp. 425-432
Author(s):  
A POMIANKOWSKI ◽  
L D HURST

2021 ◽  
Author(s):  
Janne Swaegers ◽  
Rosa Ana Sanchez-Guillen ◽  
Pallavi Chauhan ◽  
Maren Wellenreuther ◽  
Bengt Hansson

Contemporary hybrid zones act as natural laboratories for the investigation of species boundaries and allow to shed light on the little understood roles of sex chromosomes in species divergence. Sex chromosomes are considered to function as a hotspot of genetic divergence between species; indicated by less genomic introgression compared to autosomes during hybridisation. Moreover, they are thought to contribute to Haldane's rule which states that hybrids of the heterogametic sex are more likely to be inviable or sterile. To test these hypotheses, we used contemporary hybrid zones of Ischnura elegans, a damselfly species that has been expanding its range into the northern and western regions of Spain, leading to chronic hybridization with its sister species Ischnura graellsii. We analysed genome-wide SNPs in the Spanish I. elegans and I. graellsii hybrid zone and found (i) that the X chromosome shows less genomic introgression compared to autosomes and (ii) that males are underrepresented among admixed individuals as predicted by Haldane's rule. This is the first study in Odonata that suggests a role of the X chromosome in reproductive isolation. Moreover, our data adds to the few studies on species with X0 sex determination system and contradicts the hypothesis that the absence of a Y chromosome causes exceptions to Haldane's rule.


2021 ◽  
Author(s):  
Neil Rosser ◽  
Nathaniel B. Edelman ◽  
Lucie M. Queste ◽  
Michaela Nelson ◽  
Fernando Seixas ◽  
...  

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