scholarly journals The rate of evolution of postmating-prezygotic reproductive isolation in Drosophila

2017 ◽  
Author(s):  
David A. Turissini ◽  
Joseph A. McGirr ◽  
Sonali S. Patel ◽  
Jean R. David ◽  
Daniel R. Matute
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Hybrid Sterility ◽  
Biological Species ◽  
Biological Species Concept ◽  
Premating Isolation ◽  
Hybrid Inviability ◽  
Systematic Analysis ◽  
Rates Of Evolution ◽  
Postzygotic Barriers

ABSTRACTReproductive isolation (RI) is an intrinsic aspect of species, as described in the Biological Species Concept. For that reason, the identification of the precise traits and mechanisms of RI, and the rates at which they evolve, is crucial to understanding how species originate and persist. Nonetheless, precise measurements of the magnitude of reproductive isolation are rare. Previous work has measured the rates of evolution of prezygotic and postzygotic barriers to gene flow, yet no systematic analysis has carried out the study of the rates of evolution of postmating-prezygotic (PMPZ) barriers. We systematically measured the magnitude of two barriers to gene flow that act after mating occurs but before zygotic fertilization and also measured a premating (female mating rate in nonchoice experiments) and two postzygotic barriers (hybrid inviability and hybrid sterility) for all pairwise crosses of species within the Drosophila melanogaster subgroup. Our results indicate that PMPZ isolation evolves faster than hybrid inviability but slower than premating isolation. We also describe seven new interspecific hybrids in the group. Our findings open up a large repertoire of tools that will enable researchers to manipulate hybrids and explore the genetic basis of interspecific differentiation, reproductive isolation, and speciation.

scholarly journals Evolution of multiple postzygotic barriers between species of the Mimulus tilingii complex

2020 ◽  
Author(s):  
Gabrielle D. Sandstedt ◽  
Carrie A. Wu ◽  
Andrea L. Sweigart
Keyword(s):  
Reproductive Isolation ◽  
Species Complex ◽  
Biological Species ◽  
Female Sterility ◽  
Biological Species Concept ◽  
Hybrid Male ◽  
F1 Hybrid ◽  
Postzygotic Barriers ◽  
Geographic Separation ◽  
Male And Female Sterility

ABSTRACTSpecies are often defined by their ability to interbreed (i.e., Biological Species Concept), but determining how and why reproductive isolation arises between new species can be challenging. In the Mimulus tilingii species complex, three species (M. caespitosa, M. minor, and M. tilingii) are largely allopatric and grow exclusively at high elevations (>2000m). The extent to which geographic separation has shaped patterns of divergence among the species is not well understood. In this study, we determined that the three species are morphologically and genetically distinct, yet recently diverged (<400kya). Additionally, we performed reciprocal crosses within and between the species and identified several strong postzygotic reproductive barriers, including hybrid seed inviability, F1 hybrid necrosis, and F1 hybrid male and female sterility. In this study, such postzygotic barriers are so strong that a cross between any species pair in the M. tilingii complex would cause nearly complete reproductive isolation. We consider how geographical and topographical patterns may have facilitated the evolution of several postzygotic barriers and contributed to speciation of closely related members within the M. tilingii species complex.

scholarly journals Parthenogenesis as a solution to hybrid sterility: the mechanistic basis of meiotic distortions in clonal and sterile hybrids

2019 ◽  
Author(s):  
Dmitrij Dedukh ◽  
Zuzana Majtánová ◽  
Anatolie Marta ◽  
Martin Pšenička ◽  
Jan Kotusz ◽  
...  
Keyword(s):  
Gene Flow ◽  
Molecular Mechanisms ◽  
Hybrid Sterility ◽  
Biological Species ◽  
Female Fertility ◽  
Interspecific Gene Flow ◽  
General Validity ◽  
Specific Manner ◽  
Postzygotic Barriers ◽  
Mechanistic Basis

AbstractFormation of species generally occurs in a continuum from potentially intermixing populations to independent entities isolated from other species by pre- and postzygotic barriers. Especially the establishment of hybrid sterility (HS) is a hallmark of speciation, which usually emerges at different rates between hybrid sexes. However, although HS is frequently observed, the underlying molecular mechanisms remain poorly understood. Here we report that speciation proceeds through a previously unnoticed stage at which gene flow is completely interrupted on side of both hybrid’s sexes, although only male hybrids are sterile, while female fertility is rescued due to a particular gametogenetic deviation leading to the formation of clonal gametes. Specifically, analysis of gametogenetic pathways in hybrids between fish species Cobitis elongatoides and C. taenia revealed that male HS resulted from extensive asynapses and crossover reduction among elongatoides-taenia chromosomal pairs followed by apoptosis. By contrast, hybrid females exhibited premeiotic genome endoreplication which ensured proper formation of bivalents between identical chromosomal copies. This deviation ultimately restored fertility in females but since it simultaneously leads to the production of unreduced clonal gametes, it restricts interspecific gene flow thereby directly contributing to speciation. In conclusion, our data demonstrate that the emergence of asexuality may remedy HS in a sex-specific manner and is intermingled with the speciation process. Although gametogenetic mechanisms employed by asexual animals and plants have rarely been scrutinized, available evidence suggests that premeiotic endoreplication is relatively widespread. This suggests that observed link between HS and clonality may have general validity in taxa able of asexual reproduction.Author’s summarySpecies are fundamental evolutionary units that presumably evolve in a continuum from potentially intermixing populations to independent entities isolated from other species by pre- and postzygotic barriers. Especially the establishment of hybrid sterility (HS) is a hallmark of speciation, which usually emerges at different rates between hybrid sexes. However, although HS is frequently observed, the underlying molecular mechanisms remain poorly understood. Here we report the existence of a previously unnoticed stage of speciation at which gene flow is completely interrupted, although only male hybrids are sterile, while female fertility is rescued due to a particular gametogenetic deviation leading to formation of clonal gametes. Specifically, HS resulted from extensive asynapses in male gonads, but in females the hybridization provoked premeiotic endoreplication which rescued chromosome pairing and fertility. Simultaneously, this meiotic deviation caused clonal transmission of maternal genome, thereby effectively restricting the interspeficic gene flow. Our results emphasize that emergence of clonality is a type of hybrid incompatibility that is intermingled with the formation of biological species and may remedy hybrid sterility in a sex-specific manner.

Not just a peep: The evolution of calling in Pseudacris crucifer

2018 ◽  
Author(s):  
Amanda Cicchino
Keyword(s):  
Reproductive Isolation ◽  
Full Range ◽  
Mate Recognition ◽  
Preliminary Evidence ◽  
Biological Species ◽  
Biological Species Concept ◽  
Incipient Species ◽  
Pseudacris Crucifer ◽  
Full Analysis ◽  
American Frog

Reproductive isolation is the hallmark of speciation as defined by the biological species concept. A species that is evolving towards reproductive isolation, but has not reached full isolation, is defined as an incipient species. One mechanism used by incipient species to further drive speciation is the use of mate recognition signals. The spring peeper, Pseudacris crucifer, is a North American frog that can be classified as an incipient species, as previous studies have found 6 distinct mitochondrial lineages within its range. Spring peepers use vocal signals for mate recognition and exhibit a female choice mating system where the males call to attract females. This study investigates the evolution of calling in spring peepers. Using calls from each lineage across the full range of spring peepers, I analyzed 11 different characteristics to determine whether the calls were different, and if so, which characteristics are being selected for. Preliminary evidence suggests that the calls between the lineages are distinct and that certain characteristics of the call are more heavily selected for than others. Full analysis on the data has not been completed at this time. This study will expand the understanding of the evolution of spring peepers, as well as offer insight into the role of mating systems on reproductive isolation.

scholarly journals Patterns of reproductive isolation in a haplodiploid mite, Amphitetranychus viennensis: prezygotic isolation, hybrid inviability and hybrid sterility

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yukie Sato ◽  
Satoshi Fujiwara ◽  
Martijn Egas ◽  
Tomoko Matsuda ◽  
Tetsuo Gotoh
Keyword(s):  
Reproductive Isolation ◽  
Genetic Distance ◽  
Spider Mite ◽  
Hybrid Sterility ◽  
Fertilization Rate ◽  
Spider Mites ◽  
Reproductive Barriers ◽  
Hybrid Female ◽  
Hybrid Inviability ◽  
Prezygotic Isolation

Abstract Background Evolution of reproductive isolation is an important process, generating biodiversity and driving speciation. To better understand this process, it is necessary to investigate factors underlying reproductive isolation through various approaches but also in various taxa. Previous studies, mainly focusing on diploid animals, supported the prevalent view that reproductive barriers evolve gradually as a by-product of genetic changes accumulated by natural selection by showing a positive relationship between the degree of reproductive isolation and genetic distance. Haplodiploid animals are expected to generate additional insight into speciation, but few studies investigated the prevalent view in haplodiploid animals. In this study, we investigate whether the relationship also holds in a haplodiploid spider mite, Amphitetranychus viennensis (Zacher). Results We sampled seven populations of the mite in the Palaearctic region, measured their genetic distance (mtDNA) and carried out cross experiments with all combinations. We analyzed how lack of fertilization rate (as measure of prezygotic isolation) as well as hybrid inviability and hybrid sterility (as measures of postzygotic isolation) varies with genetic distance. We found that the degree of reproductive isolation varies among cross combinations, and that all three measures of reproductive isolation have a positive relationship with genetic distance. Based on the mtDNA marker, lack of fertilization rate, hybrid female inviability and hybrid female sterility were estimated to be nearly complete (99.0–99.9% barrier) at genetic distances of 0.475–0.657, 0.150–0.209 and 0.145–0.210, respectively. Besides, we found asymmetries in reproductive isolation. Conclusions The prevalent view on the evolution of reproductive barriers is supported in the haplodiploid spider mite we studied here. According to the estimated minimum genetic distance for total reproductive isolation in parent population crosses in this study and previous work, a genetic distance of 0.15–0.21 in mtDNA (COI) appears required for speciation in spider mites. Variations and asymmetries in the degree of reproductive isolation highlight the importance of reinforcement of prezygotic reproductive isolation through incompatibility and the importance of cytonuclear interactions for reproductive isolation in haplodiploid spider mites.

scholarly journals Postzygotic Isolation Evolves before Prezygotic Isolation between Fresh and Saltwater Populations of the Rainwater Killifish, Lucania parva

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Genevieve M. Kozak ◽  
Arthur B. Rudolph ◽  
Beatrice L. Colon ◽  
Rebecca C. Fuller
Keyword(s):  
Reproductive Isolation ◽  
Fresh Water ◽  
Salt Water ◽  
Postzygotic Isolation ◽  
Hybrid Inviability ◽  
Prezygotic Isolation ◽  
Divergent Natural Selection ◽  
Postzygotic Barriers ◽  
Species Population ◽  
Stable Populations

Divergent natural selection has the potential to drive the evolution of reproductive isolation. The euryhaline killifish Lucania parva has stable populations in both fresh water and salt water. Lucania parva and its sister species, the freshwater L. goodei, are isolated by both prezygotic and postzygotic barriers. To further test whether adaptation to salinity has led to the evolution of these isolating barriers, we tested for incipient reproductive isolation within L. parva by crossing freshwater and saltwater populations. We found no evidence for prezygotic isolation, but reduced hybrid survival indicated that postzygotic isolation existed between L. parva populations. Therefore, postzygotic isolation evolved before prezygotic isolation in these ecologically divergent populations. Previous work on these species raised eggs with methylene blue, which acts as a fungicide. We found this fungicide distorts the pattern of postzygotic isolation by increasing fresh water survival in L. parva, masking species/population differences, and underestimating hybrid inviability.

scholarly journals Endosperm-based hybridization barriers explain the pattern of gene flow between Arabidopsis lyrata and Arabidopsis arenosa in Central Europe

2017 ◽  
Vol 114 (6) ◽  
pp. E1027-E1035 ◽  
Author(s):  
Clément Lafon-Placette ◽  
Ida M. Johannessen ◽  
Karina S. Hornslien ◽  
Mohammad F. Ali ◽  
Katrine N. Bjerkan ◽  
...  
Keyword(s):  
Gene Flow ◽  
Central Europe ◽  
Diploid Species ◽  
Biological Species ◽  
Biological Species Concept ◽  
Interspecific Gene Flow ◽  
Seed Formation ◽  
Arabidopsis Lyrata ◽  
Hybrid Seeds ◽  
Arabidopsis Arenosa

Based on the biological species concept, two species are considered distinct if reproductive barriers prevent gene flow between them. In Central Europe, the diploid species Arabidopsis lyrata and Arabidopsis arenosa are genetically isolated, thus fitting this concept as “good species.” Nonetheless, interspecific gene flow involving their tetraploid forms has been described. The reasons for this ploidy-dependent reproductive isolation remain unknown. Here, we show that hybridization between diploid A. lyrata and A. arenosa causes mainly inviable seed formation, revealing a strong postzygotic reproductive barrier separating these two species. Although viability of hybrid seeds was impaired in both directions of hybridization, the cause for seed arrest differed. Hybridization of A. lyrata seed parents with A. arenosa pollen donors resulted in failure of endosperm cellularization, whereas the endosperm of reciprocal hybrids cellularized precociously. Endosperm cellularization failure in both hybridization directions is likely causal for the embryo arrest. Importantly, natural tetraploid A. lyrata was able to form viable hybrid seeds with diploid and tetraploid A. arenosa, associated with the reestablishment of normal endosperm cellularization. Conversely, the defects of hybrid seeds between tetraploid A. arenosa and diploid A. lyrata were aggravated. According to these results, we hypothesize that a tetraploidization event in A. lyrata allowed the production of viable hybrid seeds with A. arenosa, enabling gene flow between the two species.

Appropriate delineation of species for conservation purposes

2019 ◽  
pp. 85-96
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark D. B. Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Reproductive Isolation ◽  
Biological Species ◽  
Species Concepts ◽  
Outbreeding Depression ◽  
Biological Species Concept ◽  
Genetic Rescue ◽  
Low Genetic Diversity ◽  
Inbred Populations ◽  
Species Definitions

The first step in conservation management is to delineate groups for separate versus combined management. However, there are many problems with species delineation, including diverse species definitions, lack of standardized protocols, and poor repeatability of delineations. Definitions that are too broad will lead to outbreeding depression if populations are crossed, while those that split excessively may preclude genetic rescue of small inbred populations with low genetic diversity. To minimize these problems, we recommend the use of species concepts based upon reproductive isolation (such as the Biological Species Concept) and advise against the use of Phylogenetic and General Lineage Species Concepts. We provide guidelines as to when taxonomy requires revision and outline protocols for robust species delineations.

scholarly journals MODELS OF EVOLUTION OF REPRODUCTIVE ISOLATION

Genetics ◽  
1983 ◽  
Vol 103 (3) ◽  
pp. 557-579
Author(s):  
Masatoshi Nei ◽  
Takeo Maruyama ◽  
Chung-I Wu
Keyword(s):  
Reproductive Isolation ◽  
Computer Simulations ◽  
Mutation Rate ◽  
Hybrid Sterility ◽  
Premating Isolation ◽  
Multiple Alleles ◽  
Male And Female ◽  
Postmating Isolation ◽  
Time Required ◽  
Isolation Mechanisms

ABSTRACT Mathematical models are presented for the evolution of postmating and premating reproductive isolation. In the case of postmating isolation it is assumed that hybrid sterility or inviability is caused by incompatibility of alleles at one or two loci, and evolution of reproductive isolation occurs by random fixation of different incompatibility alleles in different populations. Mutations are assumed to occur following either the stepwise mutation model or the infinite-allele model. Computer simulations by using Itô's stochastic differential equations have shown that in the model used the reproductive isolation mechanism evolves faster in small populations than in large populations when the mutation rate remains the same. In populations of a given size it evolves faster when the number of loci involved is large than when this is small. In general, however, evolution of isolation mechanisms is a very slow process, and it would take thousands to millions of generations if the mutation rate is of the order of 10-5 per generation. Since gene substitution occurs as a stochastic process, the time required for the establishment of reproductive isolation has a large variance. Although the average time of evolution of isolation mechanisms is very long, substitution of incompatibility genes in a population occurs rather quickly once it starts. The intrapopulational fertility or viability is always very high. In the model of premating isolation it is assumed that mating preference or compatibility is determined by male- and female-limited characters, each of which is controlled by a single locus with multiple alleles, and mating occurs only when the male and female characters are compatible with each other. Computer simulations have shown that the dynamics of evolution of premating isolation mechanism is very similar to that of postmating isolation mechanism, and the mean and variance of the time required for establishment of premating isolation are very large. Theoretical predictions obtained from the present study about the speed of evolution of reproductive isolation are consistent with empirical data available from vertebrate organisms.

scholarly journals Patterns of reproductive isolation in a haplodiploid mite, Amphitetranychus viennensis: prezygotic isolation, hybrid inviability and hybrid sterility

2021 ◽  
Author(s):  
Yukie Sato ◽  
Satoshi Fujiwara ◽  
Martijn Egas ◽  
Tomoko Matsuda ◽  
Tetsuo Gotoh
Keyword(s):  
Reproductive Isolation ◽  
Genetic Distance ◽  
Spider Mite ◽  
Hybrid Sterility ◽  
Fertilization Rate ◽  
Spider Mites ◽  
Reproductive Barriers ◽  
Hybrid Female ◽  
Hybrid Inviability ◽  
Prezygotic Isolation

Abstract Background Evolution of reproductive isolation is an important process, generating biodiversity and driving speciation. To better understand this process, it is necessary to investigate factors underlying reproductive isolation through various approaches but also in various taxa. Previous studies, mainly focusing on diploid animals, supported the prevalent view that reproductive barriers evolve gradually as a by-product of genetic changes accumulated by natural selection by showing a positive relationship between the degree of reproductive isolation and genetic distance. Haplodiploid animals are expected to generate additional insight into speciation, but few studies investigated the prevalent view in haplodiploid animals. In this study, we investigate whether the relationship also holds in a haplodiploid spider mite, Amphitetranychus viennensis (Zacher). Results We sampled seven populations of the mite in the Palaearctic region, measured their genetic distance (mtDNA) and carried out cross experiments with all combinations. We analyzed how lack of fertilization rate (as measure of prezygotic isolation) as well as hybrid inviability and hybrid sterility (as measures of postzygotic isolation) varies with genetic distance. We found that the degree of reproductive isolation varies among cross combinations, and that all three measures of reproductive isolation have a positive relationship with genetic distance. Based on the mtDNA marker, lack of fertilization rate, hybrid female inviability and hybrid female sterility were estimated to be nearly complete (99.0–99.9% barrier) at genetic distances of 0.475–0.657, 0.150–0.209 and 0.138–0.204, respectively. Conclusions The prevalent view on the evolution of reproductive barriers is supported in the haplodiploid spider mite we studied here. According to the estimated minimum genetic distance for total reproductive isolation in parent population crosses in this and previous studies, a genetic distance of 0.152–0.210 in mtDNA (COI) appears required for speciation in spider mites. Due to a lack of hybrid males, we could not address Haldane’s rule, which can be extended to haplodiploids, even though we focused on a young diverging group of spider mites. Our results highlight the importance of cytonuclear interactions for reproductive isolation in haplodiploid spider mites.

scholarly journals What shapes the continuum of reproductive isolation? Lessons from Heliconius butterflies

2017 ◽  
Vol 284 (1856) ◽  
pp. 20170335 ◽  
Author(s):  
C. Mérot ◽  
C. Salazar ◽  
R. M. Merrill ◽  
C. D. Jiggins ◽  
M. Joron
Keyword(s):  
Gene Flow ◽  
Mate Choice ◽  
Reproductive Isolation ◽  
Hybrid Sterility ◽  
Wing Pattern ◽  
Key Factor ◽  
Comparative Results ◽  
Phylogenetic Divergence ◽  
The Continuum

The process by which species evolve can be illuminated by investigating barriers that limit gene flow between taxa. Recent radiations, such as Heliconius butterflies, offer the opportunity to compare isolation between pairs of taxa at different stages of ecological, geographical, and phylogenetic divergence. Here, we report a comparative analysis of existing and novel data in order to quantify the strength and direction of isolating barriers within a well-studied clade of Heliconius . Our results highlight that increased divergence is associated with the accumulation of stronger and more numerous barriers to gene flow. Wing pattern is both under natural selection for Müllerian mimicry and involved in mate choice, and therefore underlies several isolating barriers. However, pairs which share a similar wing pattern also display strong reproductive isolation mediated by traits other than wing pattern. This suggests that, while wing pattern is a key factor for early stages of divergence, it may become facultative at later stages of divergence. Additional factors including habitat partitioning, hybrid sterility, and chemically mediated mate choice are associated with complete speciation. Therefore, although most previous work has emphasized the role of wing pattern, our comparative results highlight that speciation is a multi-dimensional process, whose completion is stabilized by many factors.

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