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Tumendemberel O, Hendricks SA, Hohenlohe PA, Sullivan J, Zedrosser A, Saebø M, Proctor MF, Koprowski JL, Waits LP. Range-wide evolutionary relationships and historical demography of brown bears (Ursus arctos) revealed by whole-genome sequencing of isolated central Asian populations. Mol Ecol 2023; 32:5156-5169. [PMID: 37528604 DOI: 10.1111/mec.17091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 07/02/2023] [Accepted: 07/19/2023] [Indexed: 08/03/2023]
Abstract
Phylogeographic studies uncover hidden pathways of divergence and inform conservation. Brown bears (Ursus arctos) have one of the broadest distributions of all land mammals, ranging from Eurasia to North America, and are an important model for evolutionary studies. Although several whole genomes were available for individuals from North America, Europe and Asia, limited whole-genome data were available from Central Asia, including the highly imperilled brown bears in the Gobi Desert. To fill this knowledge gap, we sequenced whole genomes from nine Asian brown bears from the Gobi Desert of Mongolia, Northern Mongolia and the Himalayas of Pakistan. We combined these data with published brown bear sequences from Europe, Asia and North America, as well as other bear species. Our goals were to determine the evolutionary relationships among brown bear populations worldwide, their genetic diversity and their historical demography. Our analyses revealed five major lineages of brown bears based on a filtered set of 684,081 single nucleotide polymorphisms. We found distinct evolutionary lineages of brown bears in the Gobi, Himalayas, northern Mongolia, Europe and North America. The lowest level of genetic diversity and the highest level of inbreeding were found in Pakistan, the Gobi Desert and Central Italy. Furthermore, the effective population size (Ne ) for all brown bears decreased over the last 70,000 years. Our results confirm the genetic distinctiveness and ancient lineage of brown bear subspecies in the Gobi Desert of Mongolia and the Himalayas of Pakistan and highlight their importance for conservation.
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Affiliation(s)
- Odbayar Tumendemberel
- Haub School of Environment and Natural Resources, University of Wyoming, Laramie, Wyoming, USA
- Department of Natural Science and Environmental Health, University of South-Eastern Norway, Bø i Telemark, Norway
| | - Sarah A Hendricks
- Institute for Interdisciplinary Data Sciences, University of Idaho, Moscow, Idaho, USA
| | - Paul A Hohenlohe
- Institute for Interdisciplinary Data Sciences, University of Idaho, Moscow, Idaho, USA
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, USA
| | - Jack Sullivan
- Institute for Interdisciplinary Data Sciences, University of Idaho, Moscow, Idaho, USA
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, USA
| | - Andreas Zedrosser
- Department of Natural Science and Environmental Health, University of South-Eastern Norway, Bø i Telemark, Norway
| | - Mona Saebø
- Department of Natural Science and Environmental Health, University of South-Eastern Norway, Bø i Telemark, Norway
| | | | - John L Koprowski
- Haub School of Environment and Natural Resources, University of Wyoming, Laramie, Wyoming, USA
| | - Lisette P Waits
- Department of Fish and Wildlife Sciences, University of Idaho, Moscow, Idaho, USA
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2
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Glasenapp MR, Pogson GH. Extensive introgression among strongylocentrotid sea urchins revealed by phylogenomics. Ecol Evol 2023; 13:e10446. [PMID: 37636863 PMCID: PMC10451471 DOI: 10.1002/ece3.10446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/01/2023] [Accepted: 08/07/2023] [Indexed: 08/29/2023] Open
Abstract
Gametic isolation is thought to play an important role in the evolution of reproductive isolation in broadcast-spawning marine invertebrates. However, it is unclear whether gametic isolation commonly evolves early in the speciation process or only accumulates after other reproductive barriers are already in place. It is also unknown whether gametic isolation is an effective barrier to introgression following speciation. Here, we used whole-genome sequencing data and multiple complementary phylogenomic approaches to test whether the well-documented gametic incompatibilities among the strongylocentrotid sea urchins have limited introgression. We quantified phylogenetic discordance, inferred reticulate phylogenetic networks, and applied the Δ statistic using gene tree topologies reconstructed from multiple sequence alignments of protein-coding single-copy orthologs. In addition, we conducted ABBA-BABA tests on genome-wide single nucleotide variants and reconstructed a phylogeny of mitochondrial genomes. Our results revealed strong mito-nuclear discordance and considerable nonrandom gene tree discordance that cannot be explained by incomplete lineage sorting alone. Eight of the nine species examined demonstrated a history of introgression with at least one other species or ancestral lineage, indicating that introgression was common during the diversification of the strongylocentrotid urchins. There was strong support for introgression between four extant species pairs (Strongylocentrotus pallidus ⇔ S. droebachiensis, S. intermedius ⇔ S. pallidus, S. purpuratus ⇔ S. fragilis, and Mesocentrotus franciscanus ⇔ Pseudocentrotus depressus) and additional evidence for introgression on internal branches of the phylogeny. Our results suggest that the existing gametic incompatibilities among the strongylocentrotid urchin species have not been a complete barrier to hybridization and introgression following speciation. Their continued divergence in the face of widespread introgression indicates that other reproductive isolating barriers likely exist and may have been more critical in establishing reproductive isolation early in speciation.
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Affiliation(s)
- Matthew R. Glasenapp
- Department of Ecology and Evolutionary BiologyUniversity of CaliforniaSanta CruzCaliforniaUSA
| | - Grant H. Pogson
- Department of Ecology and Evolutionary BiologyUniversity of CaliforniaSanta CruzCaliforniaUSA
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3
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Lollar MJ, Biewer-Heisler TJ, Danen CE, Pool JE. Hybrid breakdown in male reproduction between recently diverged Drosophila melanogaster populations has a complex and variable genetic architecture. Evolution 2023; 77:1550-1563. [PMID: 37071601 PMCID: PMC10309968 DOI: 10.1093/evolut/qpad060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 03/15/2023] [Accepted: 04/14/2023] [Indexed: 04/19/2023]
Abstract
Secondary contact between formerly isolated populations may result in hybrid breakdown, in which untested allelic combinations in hybrids are maladaptive and limit genetic exchange. Studying early-stage reproductive isolation may yield key insights into the genetic architectures and evolutionary forces underlying the first steps toward speciation. Here, we leverage the recent worldwide expansion of Drosophila melanogaster to test for hybrid breakdown between populations that diverged within the last 13,000 years. We found clear evidence for hybrid breakdown in male reproduction, but not female reproduction or viability, supporting the prediction that hybrid breakdown affects the heterogametic sex first. The frequency of non-reproducing F2 males varied among different crosses involving the same southern African and European populations, as did the qualitative effect of cross direction, implying a genetically variable basis of hybrid breakdown and a role for uniparentally inherited factors. The levels of breakdown observed in F2 males were not recapitulated in backcrossed individuals, consistent with the existence of incompatibilities with at least three partners. Thus, some of the very first steps toward reproductive isolation could involve incompatibilities with complex and variable genetic architectures. Collectively, our findings emphasize this system's potential for future studies on the genetic and organismal basis of early-stage reproductive isolation.
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Affiliation(s)
- Matthew J Lollar
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706, United States
| | | | - Clarice E Danen
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - John E Pool
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706, United States
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4
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Thomas-Bulle C, Bertrand D, Nagarajan N, Copley RR, Corre E, Hourdez S, Bonnivard É, Claridge-Chang A, Jollivet D. Genomic patterns of divergence in the early and late steps of speciation of the deep-sea vent thermophilic worms of the genus Alvinella. BMC Ecol Evol 2022; 22:106. [PMID: 36057769 PMCID: PMC9441076 DOI: 10.1186/s12862-022-02057-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 08/05/2022] [Indexed: 11/10/2022] Open
Abstract
Background The transient and fragmented nature of the deep-sea hydrothermal environment made of ridge subduction, plate collision and the emergence of new rifts is currently acting to separate of vent populations, promoting local adaptation and contributing to bursts of speciation and species specialization. The tube-dwelling worms Alvinella pompejana called the Pompeii worm and its sister species A. caudata live syntopically on the hottest part of deep-sea hydrothermal chimneys along the East Pacific Rise. They are exposed to extreme thermal and chemical gradients, which vary greatly in space and time, and thus represent ideal candidates for understanding the evolutionary mechanisms at play in the vent fauna evolution. Results We explored genomic patterns of divergence in the early and late stages of speciation of these emblematic worms using transcriptome assemblies and the first draft genome to better understand the relative role of geographic isolation and habitat preference in their genome evolution. Analyses were conducted on allopatric populations of Alvinella pompejana (early stage of separation) and between A. pompejana and its syntopic species Alvinella caudata (late stage of speciation). We first identified divergent genomic regions and targets of selection as well as their position in the genome over collections of orthologous genes and, then, described the speciation dynamics by documenting the annotation of the most divergent and/or positively selected genes involved in the isolation process. Gene mapping clearly indicated that divergent genes associated with the early stage of speciation, although accounting for nearly 30% of genes, are highly scattered in the genome without any island of divergence and not involved in gamete recognition or mito-nuclear incompatibilities. By contrast, genomes of A. pompejana and A. caudata are clearly separated with nearly all genes (96%) exhibiting high divergence. This congealing effect however seems to be linked to habitat specialization and still allows positive selection on genes involved in gamete recognition, as a possible long-duration process of species reinforcement.
Conclusion Our analyses highlight the non-negligible role of natural selection on both the early and late stages of speciation in the iconic thermophilic worms living on the walls of deep-sea hydrothermal chimneys. They shed light on the evolution of gene divergence during the process of speciation and species specialization over a very long period of time. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-022-02057-y.
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Stuckert AMM, Matute DR. Using neutral loci to quantify reproductive isolation and speciation: a commentary on Westram et al., 2022. J Evol Biol 2022; 35:1169-1174. [PMID: 36063155 DOI: 10.1111/jeb.14057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 06/20/2022] [Indexed: 01/23/2023]
Affiliation(s)
- Adam M M Stuckert
- Biology Department, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Daniel R Matute
- Biology Department, University of North Carolina, Chapel Hill, North Carolina, USA
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Abstract
Speciation is the process by which barriers to gene flow evolve between populations. Although we now know that speciation is largely driven by natural selection, knowledge of the agents of selection and the genetic and genomic mechanisms that facilitate divergence is required for a satisfactory theory of speciation. In this essay, we highlight three advances/problems in our understanding of speciation that have arisen from studies of the genes and genomic regions that underlie the evolution of reproductive isolation. First, we describe how the identification of “speciation” genes makes it possible to identify the agents of selection causing the evolution of reproductive isolation, while also noting that the link between the genetics of phenotypic divergence and intrinsic postzygotic reproductive barriers remains tenuous. Second, we discuss the important role of recombination suppressors in facilitating speciation with gene flow, but point out that the means and timing by which reproductive barriers become associated with recombination cold spots remains uncertain. Third, we establish the importance of ancient genetic variation in speciation, although we argue that the focus of speciation studies on evolutionarily young groups may bias conclusions in favor of ancient variation relative to new mutations.
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Roberts EK, Tardif S, Wright EA, Platt RN, Bradley RD, Hardy DM. Rapid divergence of a gamete recognition gene promoted macroevolution of Eutheria. Genome Biol 2022; 23:155. [PMID: 35821049 PMCID: PMC9275260 DOI: 10.1186/s13059-022-02721-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 06/29/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Speciation genes contribute disproportionately to species divergence, but few examples exist, especially in vertebrates. Here we test whether Zan, which encodes the sperm acrosomal protein zonadhesin that mediates species-specific adhesion to the egg's zona pellucida, is a speciation gene in placental mammals. RESULTS Genomic ontogeny reveals that Zan arose by repurposing of a stem vertebrate gene that was lost in multiple lineages but retained in Eutheria on acquiring a function in egg recognition. A 112-species Zan sequence phylogeny, representing 17 of 19 placental Orders, resolves all species into monophyletic groups corresponding to recognized Orders and Suborders, with <5% unsupported nodes. Three other rapidly evolving germ cell genes (Adam2, Zp2, and Prm1), a paralogous somatic cell gene (TectA), and a mitochondrial gene commonly used for phylogenetic analyses (Cytb) all yield trees with poorer resolution than the Zan tree and inferior topologies relative to a widely accepted mammalian supertree. Zan divergence by intense positive selection produces dramatic species differences in the protein's properties, with ordinal divergence rates generally reflecting species richness of placental Orders consistent with expectations for a speciation gene that acts across a wide range of taxa. Furthermore, Zan's combined phylogenetic utility and divergence exceeds those of all other genes known to have evolved in Eutheria by positive selection, including the only other mammalian speciation gene, Prdm9. CONCLUSIONS Species-specific egg recognition conferred by Zan's functional divergence served as a mode of prezygotic reproductive isolation that promoted the extraordinary adaptive radiation and success of Eutheria.
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Affiliation(s)
- Emma K. Roberts
- Department of Biological Sciences, Texas Tech University, Lubbock, TX USA
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX USA
| | - Steve Tardif
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX USA
- Reproductive Biology Division, JangoBio, Fitchburg, WI USA
| | - Emily A. Wright
- Department of Biological Sciences, Texas Tech University, Lubbock, TX USA
| | - Roy N. Platt
- Host-Pathogen Interaction Program, Texas Biomedical Research Institute, San Antonio, TX USA
| | - Robert D. Bradley
- Department of Biological Sciences, Texas Tech University, Lubbock, TX USA
- Natural Science Research Laboratory, Museum of Texas Tech University, Lubbock, TX USA
| | - Daniel M. Hardy
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX USA
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Serrato-Capuchina A, D’Agostino ERR, Peede D, Roy B, Isbell K, Wang J, Matute DR. P-elements strengthen reproductive isolation within the Drosophila simulans species complex. Evolution 2021; 75:2425-2440. [PMID: 34463356 PMCID: PMC8772388 DOI: 10.1111/evo.14319] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 04/29/2021] [Accepted: 05/06/2021] [Indexed: 11/28/2022]
Abstract
Determining mechanisms that underlie reproductive isolation (RI) is key to understanding how species boundaries are maintained in nature. Transposable elements (TEs) are ubiquitous across eukaryotic genomes. However, the role of TEs in modulating the strength of RI between species is poorly understood. Several species of Drosophila have been found to harbor P-elements (PEs), yet only D. simulans is known to be currently polymorphic for their presence in wild populations. PEs can cause RI between PE-containing (P) and PE-lacking (M) lineages of the same species. However, it is unclear whether they also contribute to the magnitude of RI between species. Here, we use the simulans species complex to assess whether differences in PE status between D. simulans and its sister species, which do not harbor PEs, contribute to multiple barriers to gene flow between species. We show that crosses involving a P D. simulans father and an M mother from a sister species exhibit lower F1 female fecundity than crosses involving an M D. simulans father and an M sister-species mother. We also find that another TE, I-element, might play a minor role in determining the frequency of dysgenesis between species. Our results suggest that the presence of PEs in a species can strengthen isolation from its sister species, providing evidence that TEs can play a role in RI.
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Affiliation(s)
- Antonio Serrato-Capuchina
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138
| | - Emmanuel R. R. D’Agostino
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514
| | - David Peede
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514
| | - Baylee Roy
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514
| | - Kristin Isbell
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514
| | - Jeremy Wang
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514
| | - Daniel R. Matute
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514
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Mass of genes rather than master genes underlie the genomic architecture of amphibian speciation. Proc Natl Acad Sci U S A 2021; 118:2103963118. [PMID: 34465621 DOI: 10.1073/pnas.2103963118] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The genetic architecture of speciation, i.e., how intrinsic genomic incompatibilities promote reproductive isolation (RI) between diverging lineages, is one of the best-kept secrets of evolution. To directly assess whether incompatibilities arise in a limited set of large-effect speciation genes, or in a multitude of loci, we examined the geographic and genomic landscapes of introgression across the hybrid zones of 41 pairs of frog and toad lineages in the Western Palearctic region. As the divergence between lineages increases, phylogeographic transitions progressively become narrower, and larger parts of the genome resist introgression. This suggests that anuran speciation proceeds through a gradual accumulation of multiple barrier loci scattered across the genome, which ultimately deplete hybrid fitness by intrinsic postzygotic isolation, with behavioral isolation being achieved only at later stages. Moreover, these loci were disproportionately sex linked in one group (Hyla) but not in others (Rana and Bufotes), implying that large X-effects are not necessarily a rule of speciation with undifferentiated sex chromosomes. The highly polygenic nature of RI and the lack of hemizygous X/Z chromosomes could explain why the speciation clock ticks slower in amphibians compared to other vertebrates. The clock-like dynamics of speciation combined with the analytical focus on hybrid zones offer perspectives for more standardized practices of species delimitation.
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Smith DA, Bennie JJ, Gordon IJ, Martin S, Ireri P, Omufwoko KS, Ffrench-Constant RH. Hybrid effects in field populations of the African monarch butterfly, Danaus chrysippus (L.) (Lepidoptera: Nymphalidae). Biol J Linn Soc Lond 2021; 133:671-684. [PMID: 34539176 PMCID: PMC8444992 DOI: 10.1093/biolinnean/blab036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 02/13/2021] [Accepted: 02/13/2021] [Indexed: 11/28/2022]
Abstract
Heterosis, Haldane and Bateson-Dobzhansky-Muller effects have been widely documented amongst a range of plants and animals. However, typically these effects are shown by taking parents of known genotype into the laboratory and measuring components of the F1 progeny under laboratory conditions. This leaves in doubt the real significance of such effects in the field. Here we use the well-known colour pattern genotypes of the African monarch or queen (Danaus chrysippus), which also control wing length, to test these effects both in the laboratory and in a contact zone in the field. By measuring the wing lengths in animals of known colour pattern genotype we show clear evidence for all three hybrid effects at the A and BC colour patterning loci, and importantly, that these same effects persist in the same presumptive F1s when measured in hybrid populations in the field. This demonstrates the power of a system in which genotypes can be directly inferred in the field and highlights that all three hybrid effects can be seen in the East African contact zone of this fascinating butterfly.
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Affiliation(s)
- David As Smith
- Natural History Museum, Eton College, Windsor SL4 6DW, UK
| | - Jon J Bennie
- Department of Geography, University of Exeter, Penryn Campus, Penryn TR10 9FE, UK
| | - Ian J Gordon
- Centre of Excellence in Biodiversity and Natural Resource Management, RN1, Huye Campus, Huye, Rwanda
| | - Simon Martin
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH1 3FL, UK
| | - Piera Ireri
- Department of Zoological Sciences, Kenyatta University, Nairobi, P.O. Box 43844-00100, Kenya
| | - Kennedy S Omufwoko
- Mpala Research Centre (Princeton University), Nanyuki, P.O. Box 555-10400, Kenya
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
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Serrato-Capuchina A, Schwochert TD, Zhang S, Roy B, Peede D, Koppelman C, Matute DR. Pure species discriminate against hybrids in the Drosophila melanogaster species subgroup. Evolution 2021; 75:1753-1774. [PMID: 34043234 DOI: 10.1111/evo.14259] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 01/20/2021] [Accepted: 02/09/2021] [Indexed: 12/11/2022]
Abstract
Introgression, the exchange of alleles between species, is a common event in nature. This transfer of alleles between species must happen through fertile hybrids. Characterizing the traits that cause defects in hybrids illuminates how and when gene flow is expected to occur. Inviability and sterility are extreme examples of fitness reductions but are not the only type of defects in hybrids. Some traits specific to hybrids are more subtle but are important to determine their fitness. In this report, we study whether F1 hybrids between two species pairs of Drosophila are as attractive as the parental species. We find that in both species pairs, the sexual attractiveness of the F1 hybrids is reduced and that pure species discriminate strongly against them. We also find that the cuticular hydrocarbon (CHC) profile of the female hybrids is intermediate between the parental species. Perfuming experiments show that modifying the CHC profile of the female hybrids to resemble pure species improves their chances of mating. Our results show that behavioral discrimination against hybrids might be an important component of the persistence of species that can hybridize.
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Affiliation(s)
- Antonio Serrato-Capuchina
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599
| | - Timothy D Schwochert
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599
| | - Stephania Zhang
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599
| | - Baylee Roy
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599
| | - David Peede
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599
| | - Caleigh Koppelman
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599
| | - Daniel R Matute
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599
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12
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Hill T, Rosales-Stephens HL, Unckless RL. Rapid divergence of the male reproductive proteins in the Drosophila dunni group and implications for postmating incompatibilities between species. G3 (BETHESDA, MD.) 2021; 11:jkab050. [PMID: 33599779 PMCID: PMC8759818 DOI: 10.1093/g3journal/jkab050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 02/17/2021] [Indexed: 11/17/2022]
Abstract
Proteins involved in post-copulatory interactions between males and females are among the fastest evolving genes in many species, usually attributed to their involvement in reproductive conflict. As a result, these proteins are thought to often be involved in the formation of postmating-prezygotic incompatibilities between species. The Drosophila dunni subgroup consists of a dozen recently diverged species found across the Caribbean islands with varying levels of hybrid incompatibility. We performed experimental crosses between species in the dunni group and see some evidence of hybrid incompatibilities. We also find evidence of reduced survival following hybrid mating, likely due to postmating-prezygotic incompatibilities. We assessed rates of evolution between these species genomes and find evidence of rapid evolution and divergence of some reproductive proteins, specifically the seminal fluid proteins. This work suggests the rapid evolution of seminal fluid proteins may be associated with postmating-prezygotic isolation, which acts as a barrier for gene flow between even the most closely related species.
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Affiliation(s)
- Tom Hill
- The Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA
| | | | - Robert L Unckless
- The Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA
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13
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Behnke JM, Rogan MT, Craig PS, Jackson JA, Hide G. Long-term trends in helminth infections of wood mice ( Apodemus sylvaticus) from the vicinity of Malham Tarn in North Yorkshire, England. Parasitology 2021; 148:451-463. [PMID: 33256865 PMCID: PMC11010161 DOI: 10.1017/s0031182020002243] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 11/03/2020] [Accepted: 11/24/2020] [Indexed: 12/22/2022]
Abstract
Helminth infections in wood mice (n = 483), trapped over a period of 26 years in the woods surrounding Malham Tarn in North Yorkshire, were analysed. Although 10 species of helminths were identified, the overall mean species richness was 1.01 species/mouse indicating that the helminth community was relatively depauperate in this wood mouse population. The dominant species was Heligmosomoides polygyrus, the prevalence (64.6%) and abundance (10.4 worms/mouse) of which declined significantly over the study period. Because of the dominance of this species, analyses of higher taxa (combined helminths and combined nematodes) also revealed significantly declining values for prevalence, although not abundance. Helminth species richness (HSR) and Brillouin's index of diversity (BID) did not show covariance with year, neither did those remaining species whose overall prevalence exceeded 5% (Syphacia stroma, Aonchotheca murissylvatici and Plagiorchis muris). Significant age effects were detected for the prevalence and abundance of all higher taxa, H. polygyrus and P. muris, and for HSR and BID, reflecting the accumulation of helminths with increasing host age. Only two cases of sex bias were found; male bias in abundance of P. muris and combined Digenea. We discuss the significance of these results and hypothesize about the underlying causes.
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Affiliation(s)
- Jerzy M. Behnke
- School of Life Sciences, University of Nottingham, University Park, NottinghamNG7 2RD, UK
| | - Michael T. Rogan
- Biomedical Research Centre, School of Science, Engineering and Environment, University of Salford, SalfordM5 4WT, UK
| | - Philip S. Craig
- Biomedical Research Centre, School of Science, Engineering and Environment, University of Salford, SalfordM5 4WT, UK
| | - Joseph A. Jackson
- Biomedical Research Centre, School of Science, Engineering and Environment, University of Salford, SalfordM5 4WT, UK
| | - Geoff Hide
- Biomedical Research Centre, School of Science, Engineering and Environment, University of Salford, SalfordM5 4WT, UK
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14
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Matute DR, Cooper BS. Comparative studies on speciation: 30 years since Coyne and Orr. Evolution 2021; 75:764-778. [PMID: 33491225 PMCID: PMC8247902 DOI: 10.1111/evo.14181] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 12/16/2020] [Accepted: 12/22/2020] [Indexed: 12/28/2022]
Abstract
Understanding the processes of population divergence and speciation remains a core question in evolutionary biology. For nearly a hundred years evolutionary geneticists have characterized reproductive isolation (RI) mechanisms and specific barriers to gene flow required for species formation. The seminal work of Coyne and Orr provided the first comprehensive comparative analysis of speciation. By combining phylogenetic hypotheses and species range data with estimates of genetic divergence and multiple mechanisms of RI across Drosophila, Coyne and Orr's influential meta-analyses answered fundamental questions and motivated new analyses that continue to push the field forward today. Now 30 years later, we revisit the five questions addressed by Coyne and Orr, identifying results that remain well supported and others that seem less robust with new data. We then consider the future of speciation research, with emphasis on areas where novel methods and data motivate potential progress. While the literature remains biased towards Drosophila and other model systems, we are enthusiastic about the future of the field.
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Affiliation(s)
- Daniel R. Matute
- Biology DepartmentUniversity of North CarolinaChapel HillNorth Carolina27510
| | - Brandon S. Cooper
- Division of Biological SciencesUniversity of MontanaMissoulaMontana59812
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15
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Adashev VE, Kotov AA, Bazylev SS, Shatskikh AS, Aravin AA, Olenina LV. Stellate Genes and the piRNA Pathway in Speciation and Reproductive Isolation of Drosophila melanogaster. Front Genet 2021; 11:610665. [PMID: 33584811 PMCID: PMC7874207 DOI: 10.3389/fgene.2020.610665] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Accepted: 12/29/2020] [Indexed: 12/12/2022] Open
Abstract
One of the main conditions of the species splitting from a common precursor lineage is the prevention of a gene flow between diverging populations. The study of Drosophila interspecific hybrids allows to reconstruct the speciation mechanisms and to identify hybrid incompatibility factors that maintain post-zygotic reproductive isolation between closely related species. The regulation, evolution, and maintenance of the testis-specific Ste-Su(Ste) genetic system in Drosophila melanogaster is the subject of investigation worldwide. X-linked tandem testis-specific Stellate genes encode proteins homologous to the regulatory β-subunit of protein kinase CK2, but they are permanently repressed in wild-type flies by the piRNA pathway via piRNAs originating from the homologous Y-linked Su(Ste) locus. Derepression of Stellate genes caused by Su(Ste) piRNA biogenesis disruption leads to the accumulation of crystalline aggregates in spermatocytes, meiotic defects and male sterility. In this review we summarize current data about the origin, organization, evolution of the Ste-Su(Ste) system, and piRNA-dependent regulation of Stellate expression. The Ste-Su(Ste) system is fixed only in the D. melanogaster genome. According to our hypothesis, the acquisition of the Ste-Su(Ste) system by a part of the ancient fly population appears to be the causative factor of hybrid sterility in crosses of female flies with males that do not carry Y-linked Su(Ste) repeats. To support this scenario, we have directly demonstrated Stellate derepression and the corresponding meiotic disorders in the testes of interspecies hybrids between D. melanogaster and D. mauritiana. This finding embraces our hypothesis about the contribution of the Ste-Su(Ste) system and the piRNA pathway to the emergence of reproductive isolation of D. melanogaster lineage from initial species.
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Affiliation(s)
- Vladimir E. Adashev
- Laboratory of Biochemical Genetics of Animals, Institute of Molecular Genetics, National Research Centre “Kurchatov Institute”, Moscow, Russia
| | - Alexei A. Kotov
- Laboratory of Biochemical Genetics of Animals, Institute of Molecular Genetics, National Research Centre “Kurchatov Institute”, Moscow, Russia
| | - Sergei S. Bazylev
- Laboratory of Biochemical Genetics of Animals, Institute of Molecular Genetics, National Research Centre “Kurchatov Institute”, Moscow, Russia
| | - Aleksei S. Shatskikh
- Laboratory of Analysis of Clinical and Model Tumor Pathologies at the Organismal Level, Institute of Molecular Genetics, National Research Centre “Kurchatov Institute”, Moscow, Russia
| | - Alexei A. Aravin
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, United States
| | - Ludmila V. Olenina
- Laboratory of Biochemical Genetics of Animals, Institute of Molecular Genetics, National Research Centre “Kurchatov Institute”, Moscow, Russia
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16
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Talavera JB, Collosi E, Clark MI, Robertson JM, Gray DA. Minimal prezygotic isolation between ecologically divergent sibling species. Biol J Linn Soc Lond 2021; 132:32-43. [PMID: 33390615 PMCID: PMC7761596 DOI: 10.1093/biolinnean/blaa178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 09/28/2020] [Indexed: 11/14/2022]
Abstract
Divergence in mating signals typically accompanies speciation. We examine two ecologically divergent sibling species of crickets to assess the degree and timing of the evolution of prezygotic reproductive isolation. Gryllus saxatilis occurs in rocky habitats throughout western North America with long-winged individuals capable of long-distance dispersal; Gryllus navajo is endemic to red-rock sandstone areas of south-eastern Utah and north-eastern Arizona and has short-winged individuals only capable of limited dispersal. Previous genetic work suggested some degree of introgression and/or incomplete lineage sorting is likely. Here we: (1) use restriction site associated DNA sequencing (RAD-seq) genetic data to describe the degree of genetic divergence among species and populations; (2) examine the strength of prezygotic isolation by (i) quantifying differences among male mating songs, and (ii) testing whether females prefer G. saxatilis or G. navajo calling songs. Our results show that genetically distinct "pure" species populations and genetically intermediate populations exist. Male mating songs are statistically distinguishable, but the absolute differences are small. In playback experiments, females from pure populations had no preference based on song; however, females from a genetically intermediate population preferred G. navajo song. Together these results suggest that prezygotic isolation is minimal, and mediated by female behaviour in admixed populations.
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Affiliation(s)
- Janelle B Talavera
- Department of Biology, California State University, Northridge, Northridge, CA, USA
| | - Emma Collosi
- Department of Biology, California State University, Northridge, Northridge, CA, USA
| | - Meaghan I Clark
- Department of Biology, California State University, Northridge, Northridge, CA, USA
| | - Jeanne M Robertson
- Department of Biology, California State University, Northridge, Northridge, CA, USA
| | - David A Gray
- Department of Biology, California State University, Northridge, Northridge, CA, USA
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17
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Balfour VL, Black D, Shuker DM. A single pleiotropic locus influences the rate of hybridization between two sibling species of Lygaeus bugs. Ecol Evol 2020; 10:12224-12232. [PMID: 33209283 PMCID: PMC7663077 DOI: 10.1002/ece3.6853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 09/08/2020] [Indexed: 11/21/2022] Open
Abstract
The evolution of reproductive isolation lies at the heart of understanding the process of speciation. Of particular interest is the relationship between pre- and postzygotic reproductive isolation, and the genetic architecture of traits that contribute to one or both forms of reproductive isolation. The sibling species of seed bug Lygaeus equestris and L. simulans show a classic pattern of asymmetric prezygotic reproductive isolation, with female L. equestris hybridizing with male L. simulans, but with no hybridization in the reciprocal direction. We have recently described a mutant pale color form of L. simulans, that inherits as a single Mendelian locus and is pleiotropic for a number of other life history and behavioral traits. Here, we tested whether this locus also influences pre- and postzygotic reproductive isolation. Two sets of experimental crosses revealed that behavioral isolation varied with mutant versus wild-type phenotype for male L. simulans, with the pale form less successful at mating with female L. equestris. In terms of trying to assess postzygotic isolation, levels of hybrid offspring production were uniformly low across the experiments. However, we did obtain, for the first time, hybrid offspring from a pairing between a female L. simulans and a male L. equestris. In this instance, the female was of the pale mutant genotype. Together with evidence for heterozygote advantage in terms of nymph survival, we consider our results in terms of possible mechanisms of reproductive isolation between this species pair, the role of the pale mutation, and the possible genetic architectures underlying the mutation, from a single gene to a supergene.
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18
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Rosser N, Queste LM, Cama B, Edelman NB, Mann F, Mori Pezo R, Morris J, Segami C, Velado P, Schulz S, Mallet JLB, Dasmahapatra KK. Geographic contrasts between pre- and postzygotic barriers are consistent with reinforcement in Heliconius butterflies. Evolution 2020; 73:1821-1838. [PMID: 31334832 PMCID: PMC6771877 DOI: 10.1111/evo.13804] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 05/15/2019] [Accepted: 05/20/2019] [Indexed: 12/20/2022]
Abstract
Identifying the traits causing reproductive isolation and the order in which they evolve is fundamental to understanding speciation. Here, we quantify prezygotic and intrinsic postzygotic isolation among allopatric, parapatric, and sympatric populations of the butterflies Heliconius elevatus and Heliconius pardalinus. Sympatric populations from the Amazon (H. elevatus and H. p. butleri) exhibit strong prezygotic isolation and rarely mate in captivity; however, hybrids are fertile. Allopatric populations from the Amazon (H. p. butleri) and Andes (H. p. sergestus) mate freely when brought together in captivity, but the female F1 hybrids are sterile. Parapatric populations (H. elevatus and H. p. sergestus) exhibit both assortative mating and sterility of female F1s. Assortative mating in sympatric populations is consistent with reinforcement in the face of gene flow, where the driving force, selection against hybrids, is due to disruption of mimicry and other ecological traits rather than hybrid sterility. In contrast, the lack of assortative mating and hybrid sterility observed in allopatric populations suggests that geographic isolation enables the evolution of intrinsic postzygotic reproductive isolation. Our results show how the types of reproductive barriers that evolve between species may depend on geography.
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Affiliation(s)
- Neil Rosser
- Department of Biology, University of York, Wentworth Way, Heslington, YO10 5DD, United Kingdom.,Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, 02138
| | - Lucie M Queste
- Department of Biology, University of York, Wentworth Way, Heslington, YO10 5DD, United Kingdom
| | - Bruna Cama
- Department of Biology, University of York, Wentworth Way, Heslington, YO10 5DD, United Kingdom
| | - Nathaniel B Edelman
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, 02138
| | - Florian Mann
- Institut für Organische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106, Braunschweig, Germany
| | - Ronald Mori Pezo
- URKU Estudios Amazónicos, Jr. Saposoa 181, Tarapoto, San Martín, Perú
| | - Jake Morris
- Department of Biology, University of York, Wentworth Way, Heslington, YO10 5DD, United Kingdom
| | - Carolina Segami
- Department of Ecology and Genetics, Uppsala University, Norbyvägen 18d, 75236, Uppsala, Sweden
| | - Patricia Velado
- Department for Quality Assurance Analytics, Bavarian State Research Center for Agriculture, Lange Point 6, 85354, Freising, Germany
| | - Stefan Schulz
- Institut für Organische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106, Braunschweig, Germany
| | - James L B Mallet
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, 02138
| | - Kanchon K Dasmahapatra
- Department of Biology, University of York, Wentworth Way, Heslington, YO10 5DD, United Kingdom
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19
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Ahmed OM, Avila-Herrera A, Tun KM, Serpa PH, Peng J, Parthasarathy S, Knapp JM, Stern DL, Davis GW, Pollard KS, Shah NM. Evolution of Mechanisms that Control Mating in Drosophila Males. Cell Rep 2020; 27:2527-2536.e4. [PMID: 31141679 PMCID: PMC6646047 DOI: 10.1016/j.celrep.2019.04.104] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 02/20/2019] [Accepted: 04/23/2019] [Indexed: 11/17/2022] Open
Abstract
Genetically wired neural mechanisms inhibit mating between species
because even naive animals rarely mate with other species. These mechanisms can
evolve through changes in expression or function of key genes in sensory
pathways or central circuits. Gr32a is a gustatory chemoreceptor that, in
D. melanogaster, is essential to inhibit interspecies
courtship and sense quinine. Similar to D. melanogaster, we
find that D. simulans Gr32a is expressed in foreleg tarsi,
sensorimotor appendages that inhibit interspecies courtship, and it is required
to sense quinine. Nevertheless, Gr32a is not required to inhibit interspecies
mating by D. simulans males. However, and similar to its
function in D. melanogaster, Ppk25, a member of the Pickpocket
family, promotes conspecific courtship in D. simulans.
Together, we have identified distinct evolutionary mechanisms underlying
chemosensory control of taste and courtship in closely related
Drosophila species. Mechanisms that inhibit interspecies mating are critical to reproductive
isolation of species. Ahmed et al. show that Gr32a, a chemoreceptor that
inhibits interspecies courtship by D. melanogaster males, does
not inhibit this behavior in the closely related D. simulans,
indicating rapid evolution of peripheral sensory mechanisms that preclude
interspecies breeding.
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Affiliation(s)
- Osama M Ahmed
- Program in Neuroscience, University of California, San Francisco, San Francisco, CA 94143, USA; Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08540, USA
| | - Aram Avila-Herrera
- Integrative Program in Quantitative Biology, University of California, San Francisco, San Francisco, CA 94158, USA; Computation Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; Gladstone Institutes, San Francisco, CA 94158, USA
| | - Khin May Tun
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Paula H Serpa
- Integrative Program in Quantitative Biology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Justin Peng
- Integrative Program in Quantitative Biology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Srinivas Parthasarathy
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, USA; L.E.K. Consulting, 75 State Street, Boston, MA 02109, USA
| | - Jon-Michael Knapp
- Department of Neurobiology, Stanford University, Stanford, CA 94305, USA; Janelia Research Campus, HHMI Ashburn, Ashburn, VA 20147, USA
| | - David L Stern
- Janelia Research Campus, HHMI Ashburn, Ashburn, VA 20147, USA
| | - Graeme W Davis
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Katherine S Pollard
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA 94158, USA; Gladstone Institutes, San Francisco, CA 94158, USA
| | - Nirao M Shah
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, USA; Department of Neurobiology, Stanford University, Stanford, CA 94305, USA; Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA.
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20
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Tobler M, Barts N, Greenway R. Mitochondria and the Origin of Species: Bridging Genetic and Ecological Perspectives on Speciation Processes. Integr Comp Biol 2020; 59:900-911. [PMID: 31004483 DOI: 10.1093/icb/icz025] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Mitochondria have been known to be involved in speciation through the generation of Dobzhansky-Muller incompatibilities, where functionally neutral co-evolution between mitochondrial and nuclear genomes can cause dysfunction when alleles are recombined in hybrids. We propose that adaptive mitochondrial divergence between populations can not only produce intrinsic (Dobzhansky-Muller) incompatibilities, but could also contribute to reproductive isolation through natural and sexual selection against migrants, post-mating prezygotic isolation, as well as by causing extrinsic reductions in hybrid fitness. We describe how these reproductive isolating barriers can potentially arise through adaptive divergence of mitochondrial function in the absence of mito-nuclear coevolution, a departure from more established views. While a role for mitochondria in the speciation process appears promising, we also highlight critical gaps of knowledge: (1) many systems with a potential for mitochondrially-mediated reproductive isolation lack crucial evidence directly linking reproductive isolation and mitochondrial function; (2) it often remains to be seen if mitochondrial barriers are a driver or a consequence of reproductive isolation; (3) the presence of substantial gene flow in the presence of mito-nuclear incompatibilities raises questions whether such incompatibilities are strong enough to drive speciation to completion; and (4) it remains to be tested how mitochondrial effects on reproductive isolation compare when multiple mechanisms of reproductive isolation coincide. We hope this perspective and the proposed research plans help to inform future studies of mitochondrial adaptation in a manner that links genotypic changes to phenotypic adaptations, fitness, and reproductive isolation in natural systems, helping to clarify the importance of mitochondria in the formation and maintenance of biological diversity.
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Affiliation(s)
- M Tobler
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - N Barts
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - R Greenway
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
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21
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Babiychuk E, Teixeira JG, Tyski L, Guimaraes JTF, Romeiro LA, da Silva EF, Dos Santos JF, Vasconcelos S, da Silva DF, Castilho A, Siqueira JO, Fonseca VLI, Kushnir S. Geography is essential for reproductive isolation between florally diversified morning glory species from Amazon canga savannahs. Sci Rep 2019; 9:18052. [PMID: 31792228 PMCID: PMC6889514 DOI: 10.1038/s41598-019-53853-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 11/06/2019] [Indexed: 11/29/2022] Open
Abstract
The variety, relative importance and eco-evolutionary stability of reproductive barriers are critical to understanding the processes of speciation and species persistence. Here we evaluated the strength of the biotic prezygotic and postzygotic isolation barriers between closely related morning glory species from Amazon canga savannahs. The flower geometry and flower visitor assemblage analyses supported pollination by the bees in lavender-flowered Ipomoea marabaensis and recruitment of hummingbirds as pollinators in red-flowered Ipomoea cavalcantei. Nevertheless, native bee species and alien honeybees foraged on flowers of both species. Real-time interspecific hybridization underscored functionality of the overlap in flower visitor assemblages, questioning the strength of prezygotic isolation underpinned by diversification in flower colour and geometry. Interspecific hybrids were fertile and produced offspring in nature. No significant asymmetry in interspecific hybridization and hybrid incompatibilities among offspring were found, indicating weak postmating and postzygotic isolation. The results suggested that despite floral diversification, the insular-type geographic isolation remains a major barrier to gene flow. Findings set a framework for the future analysis of contemporary evolution of plant-pollinator networks at the population, community, and ecosystem levels in tropical ecosystems that are known to be distinct from the more familiar temperate climate models.
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Affiliation(s)
- Elena Babiychuk
- Instituto Tecnológico Vale, Rua Boaventura da Silva 955, CEP 66055-090, Belém, Pará, Brazil.
| | | | - Lourival Tyski
- Parque Zoobotânico Vale, VALE S.A., Rod. Raimundo Mascarenhas, Km 26, S/N., Núcleo Urbano de Carajás, CEP 68516-000, Parauapebas, Pará, Brazil
| | | | - Luiza Araújo Romeiro
- Instituto Tecnológico Vale, Rua Boaventura da Silva 955, CEP 66055-090, Belém, Pará, Brazil
| | | | | | - Santelmo Vasconcelos
- Instituto Tecnológico Vale, Rua Boaventura da Silva 955, CEP 66055-090, Belém, Pará, Brazil
| | - Delmo Fonseca da Silva
- Parque Zoobotânico Vale, VALE S.A., Rod. Raimundo Mascarenhas, Km 26, S/N., Núcleo Urbano de Carajás, CEP 68516-000, Parauapebas, Pará, Brazil
| | - Alexandre Castilho
- Gerência de Meio Ambiente, Departamento de Ferrosos Corredor Norte, Vale S.A., Rua Guamá n 60, Núcleo Urbano, CEP 68516-000, Parauapebas, Pará, Brazil
| | - José Oswaldo Siqueira
- Instituto Tecnológico Vale, Rua Boaventura da Silva 955, CEP 66055-090, Belém, Pará, Brazil
| | | | - Sergei Kushnir
- Unaffiliated, Belém, Pará, Brazil.,Teagasc, Crop Science Department, Oak Park, Carlow, R93 XE12, Ireland
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22
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Plakke MS, Walker JL, Lombardo JB, Goetz BJ, Pacella GN, Durrant JD, Clark NL, Morehouse NI. Characterization of Female Reproductive Proteases in a Butterfly from Functional and Evolutionary Perspectives. Physiol Biochem Zool 2019; 92:579-590. [DOI: 10.1086/705722] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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23
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Lustyk D, Kinský S, Ullrich KK, Yancoskie M, Kašíková L, Gergelits V, Sedlacek R, Chan YF, Odenthal-Hesse L, Forejt J, Jansa P. Genomic Structure of Hstx2 Modifier of Prdm9-Dependent Hybrid Male Sterility in Mice. Genetics 2019; 213:1047-1063. [PMID: 31562180 PMCID: PMC6827376 DOI: 10.1534/genetics.119.302554] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 09/23/2019] [Indexed: 02/06/2023] Open
Abstract
F1 hybrids between mouse inbred strains PWD and C57BL/6 represent the most thoroughly genetically defined model of hybrid sterility in vertebrates. Hybrid male sterility can be fully reconstituted from three components of this model, the Prdm9 gene, intersubspecific homeology of Mus musculus musculus and Mus musculus domesticus autosomes, and the X-linked Hstx2 locus. Hstx2 modulates the extent of Prdm9-dependent meiotic arrest and harbors two additional factors responsible for intersubspecific introgression-induced oligospermia (Hstx1) and meiotic recombination rate (Meir1). To facilitate positional cloning and to overcome the recombination suppression within the 4.3 Mb encompassing the Hstx2 locus, we designed Hstx2-CRISPR and SPO11/Cas9 transgenes aimed to induce DNA double-strand breaks specifically within the Hstx2 locus. The resulting recombinant reduced the Hstx2 locus to 2.70 Mb (chromosome X: 66.51-69.21 Mb). The newly defined Hstx2 locus still operates as the major X-linked factor of the F1 hybrid sterility, and controls meiotic chromosome synapsis and meiotic recombination rate. Despite extensive further crosses, the 2.70 Mb Hstx2 interval behaved as a recombination cold spot with reduced PRDM9-mediated H3K4me3 hotspots and absence of DMC1-defined DNA double-strand-break hotspots. To search for structural anomalies as a possible cause of recombination suppression, we used optical mapping and observed high incidence of subspecies-specific structural variants along the X chromosome, with a striking copy number polymorphism of the microRNA Mir465 cluster. This observation together with the absence of a strong sterility phenotype in Fmr1 neighbor (Fmr1nb) null mutants support the role of microRNA as a likely candidate for Hstx2.
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Affiliation(s)
- Diana Lustyk
- Laboratory of Mouse Molecular Genetics, Division BIOCEV, Institute of Molecular Genetics, Czech Academy of Sciences, Vestec CZ-25250, Czech Republic
- Faculty of Science, Charles University, Prague CZ-12000, Czech Republic
| | - Slavomír Kinský
- The Czech Centre for Phenogenomics, Division BIOCEV, Institute of Molecular Genetics, Czech Academy of Sciences, Vestec CZ-25250, Czech Republic
| | - Kristian Karsten Ullrich
- Department Evolutionary Genetics, Research Group Meiotic Recombination and Genome Instability, Max Planck Institute for Evolutionary Biology, Plön D-24306, Germany
| | - Michelle Yancoskie
- Molecular Basis and Evolution of Complex Traits Group, Friedrich Miescher Laboratory of the Max Planck Society, Tübingen 72076, Germany
| | - Lenka Kašíková
- Laboratory of Mouse Molecular Genetics, Division BIOCEV, Institute of Molecular Genetics, Czech Academy of Sciences, Vestec CZ-25250, Czech Republic
| | - Vaclav Gergelits
- Laboratory of Mouse Molecular Genetics, Division BIOCEV, Institute of Molecular Genetics, Czech Academy of Sciences, Vestec CZ-25250, Czech Republic
| | - Radislav Sedlacek
- The Czech Centre for Phenogenomics, Division BIOCEV, Institute of Molecular Genetics, Czech Academy of Sciences, Vestec CZ-25250, Czech Republic
| | - Yingguang Frank Chan
- Molecular Basis and Evolution of Complex Traits Group, Friedrich Miescher Laboratory of the Max Planck Society, Tübingen 72076, Germany
| | - Linda Odenthal-Hesse
- Department Evolutionary Genetics, Research Group Meiotic Recombination and Genome Instability, Max Planck Institute for Evolutionary Biology, Plön D-24306, Germany
| | - Jiri Forejt
- Laboratory of Mouse Molecular Genetics, Division BIOCEV, Institute of Molecular Genetics, Czech Academy of Sciences, Vestec CZ-25250, Czech Republic
| | - Petr Jansa
- Laboratory of Mouse Molecular Genetics, Division BIOCEV, Institute of Molecular Genetics, Czech Academy of Sciences, Vestec CZ-25250, Czech Republic
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24
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Doellman MM, Feder JL. Genomic transitions during host race and species formation. CURRENT OPINION IN INSECT SCIENCE 2019; 31:84-92. [PMID: 31109679 DOI: 10.1016/j.cois.2018.11.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 11/19/2018] [Accepted: 11/20/2018] [Indexed: 06/09/2023]
Abstract
Darwin recognized species as discontinuous, yet considered them to be formed by an incremental process of natural selection. Recent theoretical work on 'genome-wide congealing' is bridging this gap between the gradualism of divergent selection and rapid genome-wide divergence, particularly during ecological speciation-with-gene-flow. Host races and species of phytophagous insects, displaying a spectrum of divergence and gene flow among member taxa, provide model systems for testing predicted non-linear transitions from 'genic' divergence at a few uncoupled loci to 'genomic' divergence with genome-wide coupling of selected loci and strong reproductive isolation. Integrating across natural history, genomics, and evolutionary theory, emerging research suggests a tipping point from 'genic' to 'genomic' divergence between host races and species, during both sympatric speciation and secondary contact.
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Affiliation(s)
- Meredith M Doellman
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Jeffrey L Feder
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
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25
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Serrato-Capuchina A, Matute DR. The Role of Transposable Elements in Speciation. Genes (Basel) 2018; 9:E254. [PMID: 29762547 PMCID: PMC5977194 DOI: 10.3390/genes9050254] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 04/26/2018] [Accepted: 04/26/2018] [Indexed: 01/20/2023] Open
Abstract
Understanding the phenotypic and molecular mechanisms that contribute to genetic diversity between and within species is fundamental in studying the evolution of species. In particular, identifying the interspecific differences that lead to the reduction or even cessation of gene flow between nascent species is one of the main goals of speciation genetic research. Transposable elements (TEs) are DNA sequences with the ability to move within genomes. TEs are ubiquitous throughout eukaryotic genomes and have been shown to alter regulatory networks, gene expression, and to rearrange genomes as a result of their transposition. However, no systematic effort has evaluated the role of TEs in speciation. We compiled the evidence for TEs as potential causes of reproductive isolation across a diversity of taxa. We find that TEs are often associated with hybrid defects that might preclude the fusion between species, but that the involvement of TEs in other barriers to gene flow different from postzygotic isolation is still relatively unknown. Finally, we list a series of guides and research avenues to disentangle the effects of TEs on the origin of new species.
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Affiliation(s)
- Antonio Serrato-Capuchina
- Biology Department, Genome Sciences Building, University of North Carolina, Chapel Hill, NC 27514, USA.
| | - Daniel R Matute
- Biology Department, Genome Sciences Building, University of North Carolina, Chapel Hill, NC 27514, USA.
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26
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Gregorova S, Gergelits V, Chvatalova I, Bhattacharyya T, Valiskova B, Fotopulosova V, Jansa P, Wiatrowska D, Forejt J. Modulation of Prdm9-controlled meiotic chromosome asynapsis overrides hybrid sterility in mice. eLife 2018. [PMID: 29537370 PMCID: PMC5902161 DOI: 10.7554/elife.34282] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Hybrid sterility is one of the reproductive isolation mechanisms leading to speciation. Prdm9, the only known vertebrate hybrid-sterility gene, causes failure of meiotic chromosome synapsis and infertility in male hybrids that are the offspring of two mouse subspecies. Within species, Prdm9 determines the sites of programmed DNA double-strand breaks (DSBs) and meiotic recombination hotspots. To investigate the relation between Prdm9-controlled meiotic arrest and asynapsis, we inserted random stretches of consubspecific homology on several autosomal pairs in sterile hybrids, and analyzed their ability to form synaptonemal complexes and to rescue male fertility. Twenty-seven or more megabases of consubspecific (belonging to the same subspecies) homology fully restored synapsis in a given autosomal pair, and we predicted that two or more DSBs within symmetric hotspots per chromosome are necessary for successful meiosis. We hypothesize that impaired recombination between evolutionarily diverged chromosomes could function as one of the mechanisms of hybrid sterility occurring in various sexually reproducing species.
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Affiliation(s)
- Sona Gregorova
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vestec, Czech Republic
| | - Vaclav Gergelits
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vestec, Czech Republic
| | - Irena Chvatalova
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vestec, Czech Republic
| | - Tanmoy Bhattacharyya
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vestec, Czech Republic
| | - Barbora Valiskova
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vestec, Czech Republic.,Faculty of Science, Charles University, Prague, Czech Republic
| | - Vladana Fotopulosova
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vestec, Czech Republic
| | - Petr Jansa
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vestec, Czech Republic
| | - Diana Wiatrowska
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vestec, Czech Republic
| | - Jiri Forejt
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vestec, Czech Republic
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27
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Shahandeh MP, Pischedda A, Turner TL. Male mate choice via cuticular hydrocarbon pheromones drives reproductive isolation between Drosophila species. Evolution 2018; 72:123-135. [PMID: 29098691 PMCID: PMC5760347 DOI: 10.1111/evo.13389] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 10/16/2017] [Accepted: 10/30/2017] [Indexed: 01/17/2023]
Abstract
Mate discrimination is a key mechanism restricting gene flow between species. While studied extensively with respect to female mate choice, mechanisms of male mate choice between species are far less studied. Thus, we have little knowledge of the relative frequency, importance, or overall contribution of male mate discrimination to reproductive isolation. In the present study, we estimated the relative contributions of male and female choice to reproductive isolation between Drosophila simulans and D. sechellia, and show that male mate discrimination accounts for the majority of the current isolation between these species. We further demonstrate that males discriminate based on female cuticular hydrocarbon pheromones, and collect evidence supporting the hypothesis that male mate discrimination may alleviate the costs associated with heterospecific courtship and mating. Our findings highlight the potentially significant contribution of male mate choice to the formation of reproductive isolating barriers, and thus the speciation process.
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Affiliation(s)
- Michael P. Shahandeh
- Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara
| | - Alison Pischedda
- Department of Biology, Barnard College, Columbia University, New York NY 10027
| | - Thomas L. Turner
- Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara
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28
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Case AL, Finseth FR, Barr CM, Fishman L. Selfish evolution of cytonuclear hybrid incompatibility in Mimulus. Proc Biol Sci 2017; 283:rspb.2016.1493. [PMID: 27629037 DOI: 10.1098/rspb.2016.1493] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Accepted: 08/23/2016] [Indexed: 11/12/2022] Open
Abstract
Intraspecific coevolution between selfish elements and suppressors may promote interspecific hybrid incompatibility, but evidence of this process is rare. Here, we use genomic data to test alternative models for the evolution of cytonuclear hybrid male sterility in Mimulus In hybrids between Iron Mountain (IM) Mimulus guttatus × Mimulus nasutus, two tightly linked M. guttatus alleles (Rf1/Rf2) each restore male fertility by suppressing a local mitochondrial male-sterility gene (IM-CMS). Unlike neutral models for the evolution of hybrid incompatibility loci, selfish evolution predicts that the Rf alleles experienced strong selection in the presence of IM-CMS. Using whole-genome sequences, we compared patterns of population-genetic variation in Rf at IM to a neighbouring population that lacks IM-CMS. Consistent with local selection in the presence of IM-CMS, the Rf region shows elevated FST, high local linkage disequilibrium and a distinct haplotype structure at IM, but not at Cone Peak (CP), suggesting a recent sweep in the presence of IM-CMS. In both populations, Rf2 exhibited lower polymorphism than other regions, but the low-diversity outliers were different between CP and IM. Our results confirm theoretical predictions of ubiquitous cytonuclear conflict in plants and provide a population-genetic mechanism for the evolution of a common form of hybrid incompatibility.
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Affiliation(s)
- Andrea L Case
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Findley R Finseth
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Camille M Barr
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Lila Fishman
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
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29
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Veale AJ, Russello MA. An ancient selective sweep linked to reproductive life history evolution in sockeye salmon. Sci Rep 2017; 7:1747. [PMID: 28496186 PMCID: PMC5431894 DOI: 10.1038/s41598-017-01890-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 04/05/2017] [Indexed: 11/09/2022] Open
Abstract
Study of parallel (or convergent) phenotypic evolution can provide important insights into processes driving sympatric, ecologically-mediated divergence and speciation, as ecotype pairs may provide a biological replicate of the underlying signals and mechanisms. Here, we provide evidence for a selective sweep creating an island of divergence associated with reproductive behavior in sockeye salmon (Oncorhynchus nerka), identifying a series of linked single nucleotide polymorphisms across a ~22,733 basepair region spanning the leucine-rich repeat-containing protein 9 gene exhibiting signatures of divergent selection associated with stream- and shore-spawning in both anadromous and resident forms across their pan-Pacific distribution. This divergence likely occurred ~3.8 Mya (95% HPD = 2.1–6.03 Mya), after sockeye separated from pink (O. gorbuscha) and chum (O. keta) salmon, but prior to the Pleistocene glaciations. Our results suggest recurrent evolution of reproductive ecotypes across the native range of O. nerka is at least partially associated with divergent selection of pre-existing genetic variation within or linked to this region. As sockeye salmon are unique among Pacific salmonids in their flexibility to spawn in lake-shore benthic environments, this region provides great promise for continued investigation of the genomic basis of O. nerka life history evolution, and, more broadly, for increasing our understanding of the heritable basis of adaptation of complex traits in novel environments.
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Affiliation(s)
- Andrew J Veale
- Department of Biology, The University of British Columbia, Okanagan Campus, 3247 University Way, Kelowna, British Columbia, V1V 1V7, Canada.,Department of Zoology, University of Otago, 340 Great King Street, Dunedin, 9016, New Zealand
| | - Michael A Russello
- Department of Biology, The University of British Columbia, Okanagan Campus, 3247 University Way, Kelowna, British Columbia, V1V 1V7, Canada.
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30
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Tipping points in the dynamics of speciation. Nat Ecol Evol 2017; 1:1. [DOI: 10.1038/s41559-016-0001] [Citation(s) in RCA: 131] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 10/11/2016] [Indexed: 01/06/2023]
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31
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Multiple Genes Cause Postmating Prezygotic Reproductive Isolation in the Drosophila virilis Group. G3-GENES GENOMES GENETICS 2016; 6:4067-4076. [PMID: 27729433 PMCID: PMC5144975 DOI: 10.1534/g3.116.033340] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Understanding the genetic basis of speciation is a central problem in evolutionary biology. Studies of reproductive isolation have provided several insights into the genetic causes of speciation, especially in taxa that lend themselves to detailed genetic scrutiny. Reproductive barriers have usually been divided into those that occur before zygote formation (prezygotic) and after (postzygotic), with the latter receiving a great deal of attention over several decades. Reproductive barriers that occur after mating but before zygote formation [postmating prezygotic (PMPZ)] are especially understudied at the genetic level. Here, I present a phenotypic and genetic analysis of a PMPZ reproductive barrier between two species of the Drosophila virilis group: D. americana and D. virilis This species pair shows strong PMPZ isolation, especially when D. americana males mate with D. virilis females: ∼99% of eggs laid after these heterospecific copulations are not fertilized. Previous work has shown that the paternal loci contributing to this incompatibility reside on two chromosomes, one of which (chromosome 5) likely carries multiple factors. The other (chromosome 2) is fixed for a paracentric inversion that encompasses nearly half the chromosome. Here, I present two results. First, I show that PMPZ in this species cross is largely due to defective sperm storage in heterospecific copulations. Second, using advanced intercross and backcross mapping approaches, I identify genomic regions that carry genes capable of rescuing heterospecific fertilization. I conclude that paternal incompatibility between D. americana males and D. virilis females is underlain by four or more genes on chromosomes 2 and 5.
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32
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Gebiola M, Kelly SE, Hammerstein P, Giorgini M, Hunter MS. “Darwin's corollary” and cytoplasmic incompatibility induced by
Cardinium
may contribute to speciation in
Encarsia
wasps (Hymenoptera: Aphelinidae). Evolution 2016; 70:2447-2458. [DOI: 10.1111/evo.13037] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 08/04/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Marco Gebiola
- Department of Entomology The University of Arizona Tucson Arizona 85721
- CNR – Istituto per la Protezione Sostenibile delle Piante Portici Italy
| | - Suzanne E. Kelly
- Department of Entomology The University of Arizona Tucson Arizona 85721
| | - Peter Hammerstein
- Institute for Theoretical Biology Humboldt‐Universität zu Berlin Philippstr. 13, Haus 4 10115 Berlin Germany
| | - Massimo Giorgini
- CNR – Istituto per la Protezione Sostenibile delle Piante Portici Italy
| | - Martha S. Hunter
- Department of Entomology The University of Arizona Tucson Arizona 85721
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33
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The Genetics of Seasonal Migration and Plumage Color. Curr Biol 2016; 26:2167-73. [DOI: 10.1016/j.cub.2016.06.015] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 05/04/2016] [Accepted: 06/13/2016] [Indexed: 12/21/2022]
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34
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Plakke MS, Deutsch AB, Meslin C, Clark NL, Morehouse NI. Dynamic digestive physiology of a female reproductive organ in a polyandrous butterfly. ACTA ACUST UNITED AC 2016; 218:1548-55. [PMID: 25994634 DOI: 10.1242/jeb.118323] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Reproductive traits experience high levels of selection because of their direct ties to fitness, often resulting in rapid adaptive evolution. Much of the work in this area has focused on male reproductive traits. However, a more comprehensive understanding of female reproductive adaptations and their relationship to male characters is crucial to uncover the relative roles of sexual cooperation and conflict in driving co-evolutionary dynamics between the sexes. We focus on the physiology of a complex female reproductive adaptation in butterflies and moths: a stomach-like organ in the female reproductive tract called the bursa copulatrix that digests the male ejaculate (spermatophore). Little is known about how the bursa digests the spermatophore. We characterized bursa proteolytic capacity in relation to female state in the polyandrous butterfly Pieris rapae. We found that the virgin bursa exhibits extremely high levels of proteolytic activity. Furthermore, in virgin females, bursal proteolytic capacity increases with time since eclosion and ambient temperature, but is not sensitive to the pre-mating social environment. Post copulation, bursal proteolytic activity decreases rapidly before rebounding toward the end of a mating cycle, suggesting active female regulation of proteolysis and/or potential quenching of proteolysis by male ejaculate constituents. Using transcriptomic and proteomic approaches, we report identities for nine proteases actively transcribed by bursal tissue and/or expressed in the bursal lumen that may contribute to observed bursal proteolysis. We discuss how these dynamic physiological characteristics may function as female adaptations resulting from sexual conflict over female remating rate in this polyandrous butterfly.
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Affiliation(s)
- Melissa S Plakke
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Aaron B Deutsch
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Camille Meslin
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Nathan L Clark
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Nathan I Morehouse
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
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35
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Delph LF, Demuth JP. Haldane’s Rule: Genetic Bases and Their Empirical Support. J Hered 2016; 107:383-91. [DOI: 10.1093/jhered/esw026] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 04/27/2016] [Indexed: 11/14/2022] Open
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36
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Martin MD, Mendelson TC. The accumulation of reproductive isolation in early stages of divergence supports a role for sexual selection. J Evol Biol 2016; 29:676-89. [PMID: 26717252 DOI: 10.1111/jeb.12819] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 12/19/2015] [Accepted: 12/21/2015] [Indexed: 11/28/2022]
Abstract
Models of speciation by sexual selection propose that male-female coevolution leads to the rapid evolution of behavioural reproductive isolation. Here, we compare the strength of behavioural isolation to ecological isolation, gametic incompatibility and hybrid inviability in a group of dichromatic stream fishes. In addition, we examine whether any of these individual barriers, or a combined measure of total isolation, is predicted by body shape differences, male colour differences, environmental differences or genetic distance. Behavioural isolation reaches the highest values of any barrier and is significantly greater than ecological isolation. No individual reproductive barrier is associated with any of the predictor variables. However, marginally significant relationships between male colour and body shape differences with ecological and behavioural isolation are discussed. Differences in male colour and body shape predict total reproductive isolation between species; hierarchical partitioning of these two variables' effects suggests a stronger role for male colour differences. Together, these results suggest an important role for divergent sexual selection in darter speciation but raise new questions about the mechanisms of sexual selection at play and the role of male nuptial ornaments.
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Affiliation(s)
- M D Martin
- Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, USA
| | - T C Mendelson
- Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, USA
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37
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Twyford AD, Streisfeld MA, Lowry DB, Friedman J. Genomic studies on the nature of species: adaptation and speciation inMimulus. Mol Ecol 2015; 24:2601-9. [DOI: 10.1111/mec.13190] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 03/25/2015] [Accepted: 03/27/2015] [Indexed: 12/27/2022]
Affiliation(s)
- Alex D. Twyford
- Ashworth Laboratories; Institute of Evolutionary Biology; The University of Edinburgh; Charlotte Auerbach Road Edinburgh EH9 3FL UK
- Department of Biology; Syracuse University; 107 College Place Syracuse NY 13244 USA
| | | | - David B. Lowry
- Plant Biology Laboratories; Department of Plant Biology; Michigan State University; 612 Wilson Road Room 166 East Lansing MI 48824 USA
| | - Jannice Friedman
- Department of Biology; Syracuse University; 107 College Place Syracuse NY 13244 USA
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38
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Abstract
Eukaryotes were born of a chimeric union between two prokaryotes--the progenitors of the mitochondrial and nuclear genomes. Early in eukaryote evolution, most mitochondrial genes were lost or transferred to the nucleus, but a core set of genes that code exclusively for products associated with the electron transport system remained in the mitochondrion. The products of these mitochondrial genes work in intimate association with the products of nuclear genes to enable oxidative phosphorylation and core energy production. The need for coadaptation, the challenge of cotransmission, and the possibility of genomic conflict between mitochondrial and nuclear genes have profound consequences for the ecology and evolution of eukaryotic life. An emerging interdisciplinary field that I call "mitonuclear ecology" is reassessing core concepts in evolutionary ecology including sexual reproduction, two sexes, sexual selection, adaptation, and speciation in light of the interactions of mitochondrial and nuclear genomes.
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39
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Delmore KE, Hübner S, Kane NC, Schuster R, Andrew RL, Câmara F, Guigó R, Irwin DE. Genomic analysis of a migratory divide reveals candidate genes for migration and implicates selective sweeps in generating islands of differentiation. Mol Ecol 2015; 24:1873-88. [DOI: 10.1111/mec.13150] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 03/06/2015] [Accepted: 03/06/2015] [Indexed: 12/18/2022]
Affiliation(s)
- Kira E. Delmore
- Department of Zoology; University of British Columbia; 6270 University Blvd Vancouver BC Canada V6T1Z4
| | - Sariel Hübner
- Department of Botany; University of British Columbia; 6270 University Blvd Vancouver BC Canada V6T1Z4
| | - Nolan C. Kane
- Ecology and Evolutionary Biology; University of Colorado at Boulder; Ramaley N122 Boulder CO 80309-0334 USA
| | - Richard Schuster
- Department of Forest and Conservation Sciences; University of British Columbia; 2424 Main Mall Vancouver BC Canada V6T1Z4
| | - Rose L. Andrew
- Molecular Ecology School of Environmental and Rural Science; University of New England Armidale; Armidale NSW 2351 Australia
| | - Francisco Câmara
- Centre for Genomic Regulation and UPF; Dr Aiguader 88 Barcelona 08003 Spain
| | - Roderic Guigó
- Centre for Genomic Regulation and UPF; Dr Aiguader 88 Barcelona 08003 Spain
| | - Darren E. Irwin
- Department of Zoology; University of British Columbia; 6270 University Blvd Vancouver BC Canada V6T1Z4
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40
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Liedvogel M, Larson KW, Lundberg M, Gursoy A, Wassenaar LI, Hobson KA, Bensch S, Akesson S. No evidence for assortative mating within a willow warbler migratory divide. Front Zool 2014; 11:52. [PMID: 25053967 PMCID: PMC4105873 DOI: 10.1186/s12983-014-0052-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 07/07/2014] [Indexed: 11/13/2022] Open
Abstract
Introduction In contact zones, genetic mixing of two taxa can be restricted by prezygotic (e.g. assortative mating) or postzygotic (lower fitness of hybrid offspring) barriers, or a combination of the two. A hybrid zone between two willow warbler subspecies (Phylloscopus trochilus trochilus, P. t. acredula) with distinctive migratory strategies occurs in central Sweden. These subspecies exhibit differences in migratory direction and distance, resulting in geographically distinct wintering areas in Africa. The subspecies may have diverged from a common refuge after the last ice age, and neutral genetic markers are homogeneous across their range. By contrast, several phenotypic traits and genetic markers of two chromosomal regions previously identified show steep clines across the divide. The evolutionary forces that maintain this migratory divide remain unknown. Here we use plumage colour, morphology, genetic markers and feather stable nitrogen-isotopes (δ15N) to assess if assortative mating between migratory phenotypes could be acting as a possible mechanism for keeping the two forms genetically separate and maintaining the migratory divide. We colour-ringed a willow warbler breeding population in the central part of the hybrid zone and observed the breeding population to assess phenotypic and genotypic traits of social pairs. Results Our data suggest that wintering area and genetic ancestry had an effect on male arrival time to the breeding grounds which could contribute to assortment. However, evidence for assortative mating could not be detected based on a comparison of plumage colour, morphology and δ15N between social mates. Conclusion This finding was strengthened by analyses of subspecies-specific genetic markers, which allowed us to identify the presence of a large proportion of potential hybrids and backcrosses at the study site. Our results supported the hypothesis that pre-mating isolation in willow warblers is weak, resulting in extensive hybridisation across the migratory divide.
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Affiliation(s)
- Miriam Liedvogel
- Center for Animal Movement Research (CAnMove), Department of Biology, Lund University, Lund, 22362, Sweden ; Wildlife Ecology and Management, Freiburg University, Tennenbacher Str. 4, Freiburg, 79106, Germany
| | - Keith W Larson
- Center for Animal Movement Research (CAnMove), Department of Biology, Lund University, Lund, 22362, Sweden
| | - Max Lundberg
- Center for Animal Movement Research (CAnMove), Department of Biology, Lund University, Lund, 22362, Sweden
| | - Arzu Gursoy
- Center for Animal Movement Research (CAnMove), Department of Biology, Lund University, Lund, 22362, Sweden ; Department of Biology, Faculty of Arts and Sciences, University of Ondokuz Mayis, Samsun, Turkey
| | | | - Keith A Hobson
- Environment Canada, 11 Innovation Blvd., Saskatoon S7N 3H5, SK, Canada
| | - Staffan Bensch
- Center for Animal Movement Research (CAnMove), Department of Biology, Lund University, Lund, 22362, Sweden
| | - Susanne Akesson
- Center for Animal Movement Research (CAnMove), Department of Biology, Lund University, Lund, 22362, Sweden
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41
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Hu XS, Yeh FC. Assessing postzygotic isolation using zygotic disequilibria in natural hybrid zones. PLoS One 2014; 9:e100568. [PMID: 24950065 PMCID: PMC4065044 DOI: 10.1371/journal.pone.0100568] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2014] [Accepted: 05/25/2014] [Indexed: 11/20/2022] Open
Abstract
Hybrid zones as windows on evolutionary processes provide a natural laboratory for studying the genetic basis and mechanisms of postzygotic isolation. One resultant pattern in hybrid zones is the Hardy-Weinberg disequilibrium (HWD) for a single locus or the linkage disequilibrium (LD) for multiple loci produced by natural selection against hybrids. However, HWD and the commonly used low-order gametic or composite digenic LD cannot fully reflect the pattern of the high-order genotypic interactions. Here we propose the use of zygotic LD to elucidate the selection mechanisms of postzygotic isolation, and its calculation is based on genotypic frequencies only, irrespective of the type of mating system. We numerically and analytically show that the maximum composite digenic LD is always greater than the maximum absolute zygotic LD under the linear-additive selection, but is comparable to or smaller than the maximum absolute zygotic LD under the strong epistatic selection. Selection mechanisms can be inferred by testing such differences. We analyze a previously reported mouse hybrid zone assayed with genome-wide SNPs, and confirm that the composite digenic LD cannot appropriately indicate all possible significant genotypic interactions for a given SNP pair. A large proportion of significant zygotic LDs, ∼75% in general in the mouse hybrid zone, cannot be revealed from the composite digenic LD analysis. Statistical tests indicate that epistatic selection occurred among multiple loci in the mouse hybrid zone. The results highlight that the joint patterns of the composite digenic and zygotic LDs can help to elucidate the selection mechanism that is potentially involved in postzygotic isolation.
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Affiliation(s)
- Xin-Sheng Hu
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
- * E-mail:
| | - Francis C. Yeh
- Department of Renewable Resources, University of Alberta, Edmonton, Canada
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42
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Vogan AA, Xu J. Evidence for genetic incompatibilities associated with post-zygotic reproductive isolation in the human fungal pathogen Cryptococcus neoformans. Genome 2014; 57:335-44. [DOI: 10.1139/gen-2014-0077] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Hybridization is a potent mechanism for generating unique strains with broad host ranges and increased virulence in fungal pathogens. In the opportunistic basidiomycete pathogen Cryptococcus neoformans, intervarietal hybrids are commonly found infecting patients. The two parental varieties C. neoformans var. grubii and C. neoformans var. neoformans mate readily under laboratory conditions, but the hybrid basidiospores have germination rates about four times lower than those from intravarietal crosses. Here, we used microdissection to collect basidiospores from a hybrid cross and analysed the genotypes of germinated basidiospores to identify potentially antagonistic allelic combinations between loci that impact basidiospore germination. Our analyses showed clear evidence for Bateson–Dobzhansky–Muller (BDM) incompatibility affecting basidiospore viability. Antagonistic combinations of alleles from both two loci and three loci were found. Interestingly, most of the hybrid progeny showed segregation distortion in favour of the alleles from var. neoformans, consistent with large-scale epistatic interactions among loci affecting basidiospore viability. Our study presents the first evidence of BDM incompatibility between nuclear genes affecting post-zygotic reproductive isolation in this model basidiomycete yeast.
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Affiliation(s)
- Aaron A. Vogan
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Jianping Xu
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
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Morgans CL, Cooke GM, Ord TJ. How populations differentiate despite gene flow: sexual and natural selection drive phenotypic divergence within a land fish, the Pacific leaping blenny. BMC Evol Biol 2014; 14:97. [PMID: 24884492 PMCID: PMC4055934 DOI: 10.1186/1471-2148-14-97] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Accepted: 03/13/2014] [Indexed: 11/10/2022] Open
Abstract
Background Divergence between populations in reproductively important features is often vital for speciation. Many studies attempt to identify the cause of population differentiation in phenotype through the study of a specific selection pressure. Holistic studies that consider the interaction of several contrasting forms of selection are more rare. Most studies also fail to consider the history of connectivity among populations and the potential for genetic drift or gene flow to facilitate or limit phenotypic divergence. We examined the interacting effects of natural selection, sexual selection and the history of connectivity on phenotypic differentiation among five populations of the Pacific leaping blenny (Alticus arnoldorum), a land fish endemic to the island of Guam. Results We found key differences among populations in two male ornaments—the size of a prominent head crest and conspicuousness of a coloured dorsal fin—that reflected a trade-off between the intensity of sexual selection (male biased sex ratios) and natural selection (exposure to predators). This differentiation in ornamentation has occurred despite evidence suggesting extensive gene flow among populations, which implies that the change in ornament expression has been recent (and potentially plastic). Conclusions Our study provides an early snapshot of divergence in reproductively important features that, regardless of whether it reflects genetic or plastic changes in phenotype, could ultimately form a reproductive barrier among populations.
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Affiliation(s)
- Courtney L Morgans
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Kensington, NSW, Australia.
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Genetics of cryptic speciation within an Arctic mustard, Draba nivalis. PLoS One 2014; 9:e93834. [PMID: 24691072 PMCID: PMC3972243 DOI: 10.1371/journal.pone.0093834] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 03/09/2014] [Indexed: 01/13/2023] Open
Abstract
Crossing experiments indicate that hybrid sterility barriers frequently have developed within diploid, circumpolar plant species of the genus Draba. To gain insight into the rapid evolution of postzygotic reproductive isolation in this system, we augmented the linkage map of one of these species, D. nivalis, and searched for quantitative trait loci (QTLs) associated with reproductive isolation. The map adds 63 new dominant markers to a previously published dataset of 31 co-dominant microsatellites. These markers include 52 amplified fragment length polymorphisms (AFLPs) and 11 sequence-specific amplified polymorphisms (SSAPs) based on retrotransposon sequence. 22 markers displaying transmission ratio distortion were further included in the map. We resolved eight linkage groups with a total map length of 894 cM. Significant genotype-trait associations, or quantitative trait loci (QTL), were detected for reproductive phenotypes including pollen fertility (4 QTLs), seed set (3 QTLs), flowering time (3 QTLs) and number of flowers (4 QTLs). Observed patterns of inheritance were consistent with the influence of both nuclear-nuclear interactions and chromosomal changes on these traits. All seed set QTLs and one pollen fertility QTL displayed underdominant effects suggestive of the involvement of chromosomal rearrangements in hybrid sterility. Interestingly, D. nivalis is predominantly self-fertilizing, which may facilitate the establishment of underdominant loci and contribute to reproductive isolation.
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Kass DH, Janoušek V, Wang L, Tucker PK. The uncharacterized gene 1700093K21Rik and flanking regions are correlated with reproductive isolation in the house mouse, Mus musculus. Mamm Genome 2014; 25:223-34. [DOI: 10.1007/s00335-014-9506-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 12/30/2013] [Indexed: 11/30/2022]
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Franchini P, Fruciano C, Spreitzer ML, Jones JC, Elmer KR, Henning F, Meyer A. Genomic architecture of ecologically divergent body shape in a pair of sympatric crater lake cichlid fishes. Mol Ecol 2013; 23:1828-45. [PMID: 24237636 DOI: 10.1111/mec.12590] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 10/18/2013] [Accepted: 10/28/2013] [Indexed: 12/26/2022]
Abstract
Determining the genetic bases of adaptations and their roles in speciation is a prominent issue in evolutionary biology. Cichlid fish species flocks are a prime example of recent rapid radiations, often associated with adaptive phenotypic divergence from a common ancestor within a short period of time. In several radiations of freshwater fishes, divergence in ecomorphological traits - including body shape, colour, lips and jaws - is thought to underlie their ecological differentiation, specialization and, ultimately, speciation. The Midas cichlid species complex (Amphilophus spp.) of Nicaragua provides one of the few known examples of sympatric speciation where species have rapidly evolved different but parallel morphologies in young crater lakes. This study identified significant QTL for body shape using SNPs generated via ddRAD sequencing and geometric morphometric analyses of a cross between two ecologically and morphologically divergent, sympatric cichlid species endemic to crater Lake Apoyo: an elongated limnetic species (Amphilophus zaliosus) and a high-bodied benthic species (Amphilophus astorquii). A total of 453 genome-wide informative SNPs were identified in 240 F2 hybrids. These markers were used to construct a genetic map in which 25 linkage groups were resolved. Seventy-two segregating SNPs were linked to 11 QTL. By annotating the two most highly supported QTL-linked genomic regions, genes that might contribute to divergence in body shape along the benthic-limnetic axis in Midas cichlid sympatric adaptive radiations were identified. These results suggest that few genomic regions of large effect contribute to early stage divergence in Midas cichlids.
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Affiliation(s)
- Paolo Franchini
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Universitätstraße 10, 78457, Konstanz, Germany
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Barreto FS, Burton RS. Elevated oxidative damage is correlated with reduced fitness in interpopulation hybrids of a marine copepod. Proc Biol Sci 2013; 280:20131521. [PMID: 23902912 DOI: 10.1098/rspb.2013.1521] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Aerobic energy production occurs via the oxidative phosphorylation pathway (OXPHOS), which is critically dependent on interactions between the 13 mitochondrial DNA (mtDNA)-encoded and approximately 70 nuclear-encoded protein subunits. Disruptive mutations in any component of OXPHOS can result in impaired ATP production and exacerbated oxidative stress; in mammalian systems, such mutations are associated with ageing as well as numerous diseases. Recent studies have suggested that oxidative stress plays a role in fitness trade-offs in life-history evolution and functional ecology. Here, we show that outcrossing between populations with divergent mtDNA can exacerbate cellular oxidative stress in hybrid offspring. In the copepod Tigriopus californicus, we found that hybrids that showed evidence of fitness breakdown (low fecundity) also exhibited elevated levels of oxidative damage to DNA, whereas those with no clear breakdown did not show significantly elevated damage. The extent of oxidative stress in hybrids appears to be dependent on the degree of genetic divergence between their respective parental populations, but this pattern requires further testing using multiple crosses at different levels of divergence. Given previous evidence in T. californicus that hybridization disrupts nuclear/mitochondrial interactions and reduces hybrid fitness, our results suggest that such negative intergenomic epistasis may also increase the production of damaging cellular oxidants; consequently, mtDNA evolution may play a significant role in generating postzygotic isolating barriers among diverging populations.
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Affiliation(s)
- Felipe S Barreto
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093, USA.
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Catchen J, Bassham S, Wilson T, Currey M, O’Brien C, Yeates Q, Cresko WA. The population structure and recent colonization history of Oregon threespine stickleback determined using restriction-site associated DNA-sequencing. Mol Ecol 2013; 22:2864-83. [PMID: 23718143 PMCID: PMC3712868 DOI: 10.1111/mec.12330] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2012] [Revised: 02/11/2013] [Accepted: 02/27/2013] [Indexed: 12/16/2022]
Abstract
Understanding how genetic variation is partitioned across genomes within and among populations is a fundamental problem in ecological and evolutionary genetics. To address this problem, we studied the threespine stickleback fish, which has repeatedly undergone parallel phenotypic and genetic differentiation when oceanic fish have invaded freshwater habitats. While significant evolutionary genetic research has been performed using stickleback from geographic regions that have been deglaciated in the last 20 000 years, less research has focused on freshwater populations that predate the last glacial maximum. We performed restriction-site associated DNA-sequencing (RAD-seq) based population genomic analyses on stickleback from across Oregon, which was not glaciated during the last maximum. We sampled stickleback from coastal, Willamette Basin and central Oregon sites, analysed their genetic diversity using RAD-seq, performed structure analyses, reconstructed their phylogeographic history and tested the hypothesis of recent stickleback introduction into central Oregon, where incidence of this species was only recently documented. Our results showed a clear phylogeographic break between coastal and inland populations, with oceanic populations exhibiting the lowest levels of divergence from one another. Willamette Basin and central Oregon populations formed a clade of closely related populations, a finding consistent with a recent introduction of stickleback into central Oregon. Finally, genome-wide analysis of genetic diversity (π) and correlations of alleles within individuals in subpopulations (FIS) supported a role for introgressive hybridization in coastal populations and a recent expansion in central Oregon. Our results exhibit the power of next-generation sequencing genomic approaches such as RAD-seq to identify both historical population structure and recent colonization history.
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Affiliation(s)
- Julian Catchen
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA 97403
| | - Susan Bassham
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA 97403
| | - Taylor Wilson
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA 97403
| | - Mark Currey
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA 97403
| | - Conor O’Brien
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA 97403
| | - Quick Yeates
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA 97403
| | - William A. Cresko
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA 97403
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Martins MJF, Mota CF, Pearson GA. Sex-biased gene expression in the brown alga Fucus vesiculosus. BMC Genomics 2013; 14:294. [PMID: 23634783 PMCID: PMC3652789 DOI: 10.1186/1471-2164-14-294] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 04/25/2013] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND The fucoid brown algae (Heterokontophyta, Phaeophyceae) are increasingly the focus of ecological genetics, biodiversity, biogeography and speciation research. The molecular genetics underlying mating system variation, where repeated dioecious - hermaphrodite switches during evolution are recognized, and the molecular evolution of sex-related genes are key questions currently hampered by a lack of genomic information. We therefore undertook a comparative analysis of male and female reproductive tissue transcriptomes against a vegetative background during natural reproductive cycles in Fucus vesiculosus. RESULTS Over 300 k reads were assembled and annotated against public protein databases including a brown alga. Compared with the vegetative tissue, photosynthetic and carbohydrate metabolism pathways were under-expressed, particularly in male tissue, while several pathways involved in genetic information processing and replication were over-expressed. Estimates of sex-biased gene (SBG) expression were higher for male (14% of annotated orthologues) than female tissue (9%) relative to the vegetative background. Mean expression levels and variance were also greater in male- than female-biased genes. Major female-biased genes were carbohydrate-modifying enzymes with likely roles in zygote cell wall biogenesis and/or modification. Male-biased genes reflected distinct sperm development and function, and orthologues for signal perception (a phototropin), transduction (several kinases), and putatively flagella-localized proteins (including candidate gamete-recognition proteins) were uniquely expressed in males. Overall, the results suggest constraint on female-biased genes (possible pleiotropy), and less constrained male-biased genes, mostly associated with sperm-specific functions. CONCLUSIONS Our results support the growing contention that males possess a large array of genes regulating male fitness, broadly supporting findings in evolutionarily distant heterogametic animal models. This work identifies an annotated set of F. vesiculosus gene products that potentially regulate sexual reproduction and may contribute to prezygotic isolation, one essential step towards developing tools for a functional understanding of species isolation and differentiation.
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Affiliation(s)
- Maria João F Martins
- CCMAR,CIMAR-Laboratório Associado, Universidade do Algarve, Gambelas, Faro 8005-139, Portugal
| | - Catarina F Mota
- CCMAR,CIMAR-Laboratório Associado, Universidade do Algarve, Gambelas, Faro 8005-139, Portugal
| | - Gareth A Pearson
- CCMAR,CIMAR-Laboratório Associado, Universidade do Algarve, Gambelas, Faro 8005-139, Portugal
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Streisfeld MA, Young WN, Sobel JM. Divergent selection drives genetic differentiation in an R2R3-MYB transcription factor that contributes to incipient speciation in Mimulus aurantiacus. PLoS Genet 2013; 9:e1003385. [PMID: 23555295 PMCID: PMC3605050 DOI: 10.1371/journal.pgen.1003385] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 01/30/2013] [Indexed: 12/30/2022] Open
Abstract
Identifying the molecular genetic basis of traits contributing to speciation is of crucial importance for understanding the ecological and evolutionary mechanisms that generate biodiversity. Despite several examples describing putative "speciation genes," it is often uncertain to what extent these genetic changes have contributed to gene flow reductions in nature. Therefore, considerable interest lies in characterizing the molecular basis of traits that actively confer reproductive isolation during the early stages of speciation, as these loci can be attributed directly to the process of divergence. In Southern California, two ecotypes of Mimulus aurantiacus are parapatric and differ primarily in flower color, with an anthocyanic, red-flowered morph in the west and an anthocyanin-lacking, yellow-flowered morph in the east. Evidence suggests that the genetic changes responsible for this shift in flower color have been essential for divergence and have become fixed in natural populations of each ecotype due to almost complete differences in pollinator preference. In this study, we demonstrate that a cis-regulatory mutation in an R2R3-MYB transcription factor results in differential regulation of enzymes in the anthocyanin biosynthetic pathway and is the major contributor to differences in floral pigmentation. In addition, molecular population genetic data show that, despite gene flow at neutral loci, divergent selection has driven the fixation of alternate alleles at this gene between ecotypes. Therefore, by identifying the genetic basis underlying ecologically based divergent selection in flower color between these ecotypes, we have revealed the ecological and functional mechanisms involved in the evolution of pre-mating isolation at the early stages of incipient speciation.
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Affiliation(s)
- Matthew A Streisfeld
- Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon, United States of America.
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