1
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Baiz MD, Wood AW, Toews DPL. Association between the gut microbiome and carotenoid plumage phenotype in an avian hybrid zone. Proc Biol Sci 2024; 291:20240238. [PMID: 38628125 PMCID: PMC11022011 DOI: 10.1098/rspb.2024.0238] [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: 02/13/2024] [Accepted: 03/18/2024] [Indexed: 04/19/2024] Open
Abstract
Vertebrates host complex microbiomes that impact their physiology. In many taxa, including colourful wood-warblers, gut microbiome similarity decreases with evolutionary distance. This may suggest that as host populations diverge, so do their microbiomes, because of either tight coevolutionary dynamics, or differential environmental influences, or both. Hybridization is common in wood-warblers, but the effects of evolutionary divergence on the microbiome during secondary contact are unclear. Here, we analyse gut microbiomes in two geographically disjunct hybrid zones between blue-winged warblers (Vermivora cyanoptera) and golden-winged warblers (Vermivora chrysoptera). We performed 16S faecal metabarcoding to identify species-specific bacteria and test the hypothesis that host admixture is associated with gut microbiome disruption. Species identity explained a small amount of variation between microbiomes in only one hybrid zone. Co-occurrence of species-specific bacteria was rare for admixed individuals, yet microbiome richness was similar among admixed and parental individuals. Unexpectedly, we found several bacteria that were more abundant among admixed individuals with a broader deposition of carotenoid-based plumage pigments. These bacteria are predicted to encode carotenoid biosynthesis genes, suggesting birds may take advantage of pigments produced by their gut microbiomes. Thus, host admixture may facilitate beneficial symbiotic interactions which contribute to plumage ornaments that function in sexual selection.
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Affiliation(s)
- Marcella D. Baiz
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260, USA
| | - Andrew W. Wood
- Department of Biology, Pennylvania State University, University Park, PA 16802, USA
| | - David P. L. Toews
- Department of Biology, Pennylvania State University, University Park, PA 16802, USA
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2
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Alario A, Trevino M, Justen H, Woodman CJ, Roth TC, Delmore KE. Learning and memory in hybrid migratory songbirds: cognition as a reproductive isolating barrier across seasons. Sci Rep 2023; 13:10866. [PMID: 37407574 DOI: 10.1038/s41598-023-37379-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 06/21/2023] [Indexed: 07/07/2023] Open
Abstract
Hybrid zones can be used to identify traits that maintain reproductive isolation and contribute to speciation. Cognitive traits may serve as post-mating reproductive isolating barriers, reducing the fitness of hybrids if, for example, misexpression occurs in hybrids and disrupts important neurological mechanisms. We tested this hypothesis in a hybrid zone between two subspecies of Swainson's thrushes (Catharus ustulatus) using two cognitive tests-an associative learning spatial test and neophobia test. We included comparisons across the sexes and seasons (spring migration and winter), testing if hybrid females performed worse than males (as per Haldane's rule) and if birds (regardless of ancestry or sex) performed better during migration, when they are building navigational maps and encountering new environments. We documented reduced cognitive abilities in hybrids, but this result was limited to males and winter. Hybrid females did not perform worse than males in either season. Although season was a significant predictor of performance, contrary to our prediction, all birds learned faster during the winter. The hypothesis that cognitive traits could serve as post-mating isolating barriers is relatively new; this is one of the first tests in a natural hybrid zone and non-food-caching species. We also provide one of the first comparisons of cognitive abilities between seasons. Future neurostructural and neurophysiological work should be used to examine mechanisms underlying our behavioral observations.
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Affiliation(s)
- Ashley Alario
- Texas A&M University, 3528 TAMU, College Station, TX, 77843, USA
| | - Marlene Trevino
- Texas A&M University, 3528 TAMU, College Station, TX, 77843, USA
| | - Hannah Justen
- Texas A&M University, 3528 TAMU, College Station, TX, 77843, USA
| | | | - Timothy C Roth
- Department of Psychology, Franklin and Marshall College, Lancaster, PA, 17603, USA
| | - Kira E Delmore
- Texas A&M University, 3528 TAMU, College Station, TX, 77843, USA.
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3
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Seifert B. A revision of the Palaearctic species of the ant genus Cardiocondyla Emery 1869 (Hymenoptera: Formicidae). Zootaxa 2023; 5274:1-64. [PMID: 37518101 DOI: 10.11646/zootaxa.5274.1.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Indexed: 08/01/2023]
Abstract
A synopsis of the Palaearctic species of the ant genus Cardiocondyla Emery 1869 is provided. The four species groups which are of Palaearctic origin or which are restricted in their distribution to this faunal zone, the C. elegans, C. ulianini, C. batesii and C. stambuloffii group-consisting of 25 recognized species-are taxonomically revised. Further nine species belonging to species groups of Ethiopic and Oriental origin which may penetrate into and build up true outdoor populations in the southern Palaearctic are only treated in the determination key. The main working rationale of this revision is Numeric Morphology-Based Alpha-Taxonomy (NUMOBAT) with formation of species hypotheses largely based on exploratory data analyses and checking these hypotheses by discriminant analysis. NUMOBAT data of the species considered comprise 727 worker samples with 1555 individuals and 23,300 primary data. Including high-resolution photos of surface microstructures, all species are depicted by z-stack imaging in four standard visual positions. Numeric data on 19 phenotypical characters are presented in comparative tables and supplementary verbal descriptions are given. In contrast to species groups with Ethiopian, Oriental and Australasian origin, no member of the four Palaearctic species groups has developed a tramp species potential to spread globally. Four cryptic species are described as new: Cardiocondyla dalmaticoides n. sp., C. caspiense n. sp., C. verdensis n. sp. and C. rolandi n. sp. Confirmed were the synonymies of Cardiocondyla elegans santschii Forel 1905, C. provincialis Bernard 1956 and Xenometra gallica Bernard 1957 with C. elegans Emery 1869, that of C. elegans eleonorae Forel 1911 with C. bulgarica Forel 1892, that of C. elegans torretassoi Finzi 1936 with C. nigra Forel 1905, and that of C. bogdanovi Ruzsky 1905, C. montandoni Santschi 1912 and C. stambuloffii taurica Karavajev 1927 with C. stambuloffii Forel 1892. Cardiocondyla bicoronata Seifert 2003 was newly synonymized with C. nigra Forel 1905.
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Affiliation(s)
- Bernhard Seifert
- Department of Entomology; Senckenberg Museum of Natural History Görlitz; Am Museum 1; 02826 Görlitz; Germany.
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4
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Coughlan JM. The role of hybrid seed inviability in angiosperm speciation. AMERICAN JOURNAL OF BOTANY 2023; 110:1-14. [PMID: 36801827 DOI: 10.1002/ajb2.16135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 01/05/2023] [Accepted: 01/05/2023] [Indexed: 05/11/2023]
Abstract
Understanding which reproductive barriers contribute to speciation is essential to understanding the diversity of life on earth. Several contemporary examples of strong hybrid seed inviability (HSI) between recently diverged species suggest that HSI may play a fundamental role in plant speciation. Yet, a broader synthesis of HSI is needed to clarify its role in diversification. Here, I review the incidence and evolution of HSI. Hybrid seed inviability is common and evolves rapidly, suggesting that it may play an important role early in speciation. The developmental mechanisms that underlie HSI involve similar developmental trajectories in endosperm, even between evolutionarily deeply diverged incidents of HSI. In hybrid endosperm, HSI is often accompanied by whole-scale gene misexpression, including misexpression of imprinted genes which have a key role in endosperm development. I explore how an evolutionary perspective can clarify the repeated and rapid evolution of HSI. In particular, I evaluate the evidence for conflict between maternal and paternal interests in resource allocation to offspring (i.e., parental conflict). I highlight that parental conflict theory generates explicit predictions regarding the expected hybrid phenotypes and genes responsible for HSI. While much phenotypic evidence supports a role of parental conflict in the evolution of HSI, an understanding of the underlying molecular mechanisms of this barrier is essential to test parental conflict theory. Lastly, I explore what factors may influence the strength of parental conflict in natural plant populations as an explanation for why rates of HSI may differ between plant groups and the consequences of strong HSI in secondary contact.
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Affiliation(s)
- Jenn M Coughlan
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, 06511, USA
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5
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Westbury MV, De Cahsan B, Shepherd LD, Holdaway RN, Duchene DA, Lorenzen ED. Genomic insights into the evolutionary relationships and demographic history of kiwi. PLoS One 2022; 17:e0266430. [PMID: 36215252 PMCID: PMC9550048 DOI: 10.1371/journal.pone.0266430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 09/26/2022] [Indexed: 11/07/2022] Open
Abstract
Kiwi are a unique and emblematic group of birds endemic to New Zealand. Deep-time evolutionary relationships among the five extant kiwi species have been difficult to resolve, in part due to the absence of pre-Quaternary fossils to inform speciation events. Here, we utilise single representative nuclear genomes of all five extant kiwi species (great spotted kiwi, little spotted kiwi, Okarito brown kiwi, North Island brown kiwi, and southern brown kiwi) and investigate their evolutionary histories with phylogenomic, genetic diversity, and deep-time (past million years) demographic analyses. We uncover relatively low levels of gene-tree phylogenetic discordance across the genomes, suggesting clear distinction between species. However, we also find indications of post-divergence gene flow, concordant with recent reports of interspecific hybrids. The four species for which unbiased levels of genetic diversity could be calculated, due to the availability of reference assemblies (all species except the southern brown kiwi), show relatively low levels of genetic diversity, which we suggest reflects a combination of older environmental as well as more recent anthropogenic influence. In addition, we suggest hypotheses regarding the impact of known past environmental events, such as volcanic eruptions and glacial periods, on the similarities and differences observed in the demographic histories of the five kiwi species over the past million years.
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Affiliation(s)
- Michael V. Westbury
- Globe Institute, University of Copenhagen, Copenhagen, Denmark
- * E-mail: (MVW); (EDL)
| | - Binia De Cahsan
- Globe Institute, University of Copenhagen, Copenhagen, Denmark
| | - Lara D. Shepherd
- Museum of New Zealand Te Papa Tongarewa, Wellington, New Zealand
| | - Richard N. Holdaway
- Palaecol Research Ltd, Christchurch, New Zealand
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
- School of Earth and Environment, University of Canterbury, Christchurch, New Zealand
| | | | - Eline D. Lorenzen
- Globe Institute, University of Copenhagen, Copenhagen, Denmark
- * E-mail: (MVW); (EDL)
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6
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Rohwer S, Wood CS, Peters JL, Miller ET, Cagley D, Butcher BG, Epperly KL, Campagna L. Interspecific forced copulations generate most hybrids in broadly sympatric ducks. PLoS One 2022; 17:e0274059. [PMID: 36126057 PMCID: PMC9488771 DOI: 10.1371/journal.pone.0274059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 08/19/2022] [Indexed: 11/22/2022] Open
Abstract
Although rare, hybrids are more common in broadly sympatric waterfowl than in any other avian family; yet, the behavioral ecology explaining their generation has remained controversial. Leading hypotheses are forced interspecific copulations, mis-imprinting caused by mixed broods, and scarcity of conspecific mates. Using a large sample of hybrid ducks solicited from North American hunters we evaluated these hypotheses by genetically determining the mother and father species of F1 hybrids. Based on abundances in areas where their breeding ranges overlap, the frequency of hybrids varied greatly from expectations, with hybrids between species within recently derived clades being much more frequent than those between more divergent clades. Forced copulations, as measured by large phallus-length asymmetries between parentals, strongly predicted the father species of most F1 hybrids. Thus, most Anas acuta x A. platyrhynchos (Northern Pintail x Mallard) F1s were sired by A. acuta, and most A. platyrhynchos x Mareca strepera (Mallard x Gadwall) F1s were sired by A. platyrhynchos. Siring asymmetries were consistent with phallus length asymmetries in five additional parental combinations, but none had samples large enough to be individually statistically significant. The exception to this trend was our sample of nine A. platyrhynchos x Mareca americana (Mallard x Gadwall) F1s, for which a large phallus asymmetry failed to predict the father species. Hybrids were rare in brood parasitic species, suggesting mis-imprinting to be an unlikely cause of most hybrids; however, our samples of hybrids from regular brood parasites were inadequate to strongly address this hypothesis. We could test the scarcity of mates hypothesis for only a single hybrid combination and it contradicted our prediction: most F1M. Penelope x M. americana (Eurasian x American Wigeon) were sired by M. penelope, strongly contradicting our prediction that female M. penelope wintering in enormous flocks of M. americana (American Wigeon) on the west coast of North America would have difficulty finding conspecific mates. In general, our results support interspecific forced copulations as the predominant behavioral mechanism generating hybrids in North temperate waterfowl.
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Affiliation(s)
- Sievert Rohwer
- Department of Biology and Burke Museum, University of Washington, Seattle, Washington, United States of America
- * E-mail:
| | - Christopher S. Wood
- Burke Museum, University of Washington, Seattle, Washington, United States of America
| | - Jefferey L. Peters
- Department of Biological Sciences, Wright State University, Dayton, Ohio, United States of America
| | | | - David Cagley
- Independent Researcher, Myrtle Point, Oregon, United States of America
| | - Bronwyn G. Butcher
- Fuller Evolutionary Biology Program, Cornell Lab of Ornithology, Ithaca, New York, United States of America
| | - Kevin L. Epperly
- Burke Museum, University of Washington, Seattle, Washington, United States of America
| | - Leonardo Campagna
- Fuller Evolutionary Biology Program, Cornell Lab of Ornithology, Ithaca, New York, United States of America
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, United States of America
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7
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Kvistad L, Falk S, Austin L. Widespread genomic signatures of reproductive isolation and sex-specific selection in the Eastern Yellow Robin, Eopsaltria australis. G3 GENES|GENOMES|GENETICS 2022; 12:6605223. [PMID: 35686912 PMCID: PMC9438485 DOI: 10.1093/g3journal/jkac145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 05/31/2022] [Indexed: 11/16/2022]
Abstract
How new species evolve is one of the most fundamental questions in biology. Population divergence, which may lead to speciation, may be occurring in the Eastern Yellow Robin, a common passerine that lives along the eastern coast of Australia. This species is composed of 2 parapatric lineages that have highly divergent mitochondrial DNA; however, similar levels of divergence have not been observed in the nuclear genome. Here we re-examine the nuclear genomes of these mitolineages to test potential mechanisms underlying the discordance between nuclear and mitochondrial divergence. We find that nuclear admixture occurs in a narrow hybrid zone, although the majority of markers across the genome show evidence of reproductive isolation between populations of opposing mitolineages. There is an 8 MB section of a previously identified putative neo-sex chromosome that is highly diverged between allopatric but not parapatric populations, which may be the result of a chromosomal inversion. The neo-sex chromosomal nature of this region, as well as the geographic patterns in which it exhibits divergence, suggest it is unlikely to be contributing to reproductive isolation through mitonuclear incompatibilities as reported in earlier studies. In addition, there are sex differences in the number of markers that are differentiated between populations of opposite mitolineages, with greater differentiation occurring in females, which are heterozygous, than males. These results suggest that, despite the absence of previously observed assortative mating, mitolineages of Eastern Yellow Robin experience at least some postzygotic isolation from each other, in a pattern consistent with Haldane’s Rule.
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Affiliation(s)
- Lynna Kvistad
- Biological Sciences, Monash University , Clayton, VIC 3800, Australia
| | - Stephanie Falk
- Biological Sciences, Monash University , Clayton, VIC 3800, Australia
- Deep Sequencing Facility, Max Planck Institute of Immunobiology and Epigenetics , Freiburg D-79108, Germany
| | - Lana Austin
- Biological Sciences, Monash University , Clayton, VIC 3800, Australia
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8
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Burbrink FT, Crother BI, Murray CM, Smith BT, Ruane S, Myers EA, Pyron RA. Empirical and philosophical problems with the subspecies rank. Ecol Evol 2022; 12:e9069. [PMID: 35845367 PMCID: PMC9271888 DOI: 10.1002/ece3.9069] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 06/01/2022] [Accepted: 06/10/2022] [Indexed: 11/12/2022] Open
Abstract
Species‐level taxonomy derives from empirical sources (data and techniques) that assess the existence of spatiotemporal evolutionary lineages via various species “concepts.” These concepts determine if observed lineages are independent given a particular methodology and ontology, which relates the metaphysical species concept to what “kind” of thing a species is in reality. Often, species concepts fail to link epistemology back to ontology. This lack of coherence is in part responsible for the persistence of the subspecies rank, which in modern usage often functions as a placeholder between the evolutionary events of divergence or collapse of incipient species. Thus, prospective events like lineages merging or diverging require information from unknowable future information. This is also conditioned on evidence that the lineage already has a detectably distinct evolutionary history. Ranking these lineages as subspecies can seem attractive given that many lineages do not exhibit intrinsic reproductive isolation. We argue that using subspecies is indefensible on philosophical and empirical grounds. Ontologically, the rank of subspecies is either identical to that of species or undefined in the context of evolutionary lineages representing spatiotemporally defined individuals. Some species concepts more inclined to consider subspecies, like the Biological Species Concept, are disconnected from evolutionary ontology and do not consider genealogy. Even if ontology is ignored, methods addressing reproductive isolation are often indirect and fail to capture the range of scenarios linking gene flow to species identity over space and time. The use of subspecies and reliance on reproductive isolation as a basis for an operational species concept can also conflict with ethical issues governing the protection of species. We provide a way forward for recognizing and naming species that links theoretical and operational species concepts regardless of the magnitude of reproductive isolation.
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Affiliation(s)
- Frank T Burbrink
- Department of Herpetology American Museum of Natural History New York New York USA
| | - Brian I Crother
- Department of Biological Sciences Southeastern Louisiana University Hammond Louisiana USA
| | - Christopher M Murray
- Department of Biological Sciences Southeastern Louisiana University Hammond Louisiana USA
| | - Brian Tilston Smith
- Department of Ornithology American Museum of Natural History New York New York USA
| | - Sara Ruane
- Life Sciences Section, Negaunee Integrative Research Center Field Museum of Natural History Chicago Illinois USA
| | - Edward A Myers
- Department of Herpetology American Museum of Natural History New York New York USA.,Department of Biological Sciences Clemson University Clemson South Carolina USA.,Department of Vertebrate Zoology Smithsonian Institution, National Museum of Natural History Washington District of Columbia USA
| | - Robert Alexander Pyron
- Department of Vertebrate Zoology Smithsonian Institution, National Museum of Natural History Washington District of Columbia USA.,Department of Biological Sciences The George Washington University Washington District of Columbia USA
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9
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Brown JI, Hernández F, Engilis A, Hernández-Baños BE, Collins D, Lavretsky P. Genomic and morphological data shed light on the complexities of shared ancestry between closely related duck species. Sci Rep 2022; 12:10212. [PMID: 35715515 PMCID: PMC9205961 DOI: 10.1038/s41598-022-14270-2] [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: 09/29/2021] [Accepted: 06/03/2022] [Indexed: 11/09/2022] Open
Abstract
Causes for genomic and morphological similarities among recently radiated species are often multifaceted and are further convoluted among species that readily interbreed. Here, we couple genomic and morphological trait comparisons to test the extent that ancestry and gene flow explain the retention of mallard-like traits within a sister species, the Mexican duck. First, we confirm that these taxa remain genetically structured, and that Mexican ducks exhibit an isolation-by-distance pattern. Despite the assumption of wide-spread hybridization, we found only a few late-stage hybrids, all from the southwestern USA. Next, assessing 23 morphological traits, we developed a genetically-vetted morphological key that is > 97% accurate in distinguishing across sex-age cohorts of Mexican ducks, mallards, and hybrids. During key development, we determined that 25% of genetically pure, immature male Mexican ducks of the northern population naturally displayed mallard-like traits in their formative plumage. In fact, applying this key to 55 museum specimens, we identified that only four of the 14 specimens originally classified as phenotypic hybrids were truly hybrids. We discuss how genomic and morphological comparisons shed light into the mechanism(s) underlying the evolution of complex phenotypic traits in recent radiations, and how misunderstanding the true morphological diversity within Mexican ducks resulted in taxonomic revisions that hindered conservation efforts.
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Affiliation(s)
- Joshua I Brown
- Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, 79968, USA.
| | - Flor Hernández
- Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, 79968, USA
| | - Andrew Engilis
- Museum of Wildlife and Fish Biology, Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, One Shields Avenue, Davis, CA, 95616, USA.,Department of Wildlife, Fish and Conservation Biology, University of California, Davis, One Shields Avenue, Davis, CA, 95616, USA
| | - Blanca E Hernández-Baños
- Departamento de Biología Evolutiva, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico, Distrito Federal, Mexico
| | - Dan Collins
- U.S. Fish and Wildlife Service - Region 2 Migratory Bird Program, Albuquerque, NM, USA
| | - Philip Lavretsky
- Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, 79968, USA
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10
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Vedder O. Experimental extra-pair copulations provide proof of concept for fertility insurance in a socially monogamous bird. Proc Biol Sci 2022; 289:20220261. [PMID: 35642374 PMCID: PMC9156919 DOI: 10.1098/rspb.2022.0261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Extra-pair paternity is common among socially monogamous birds, but whether females benefit from having extra-pair copulations remains unresolved. In this study, I staged single extra-pair copulations in captive pairs of socially monogamous Japanese quail (Coturnix japonica) and used extra-pair males of a different colour to identify extra-pair fertilizations. This eliminated among-female variation in extra-pair copulations as a source of variation in extra-pair fertilizations and tested whether a single extra-pair copulation would insure against infertility of the social male. Overall, the probability of extra-pair fertilization was 0.46 for the first egg that was fertilized after extra-pair copulation, but this rapidly declined over consecutive eggs in the laying sequence. However, a single extra-pair copulation was effective in ensuring fertilization of the majority of a typical clutch in the few cases where the social male was completely infertile. Hence, my results show that variation in extra-pair paternity can be independent from variation in extra-pair copulation behaviour and that a single, strategically timed, extra-pair copulation can largely insure against social male infertility. Among-female variation in extra-pair fertilizations, and their declining probability over the laying sequence, as typical for many bird species, can thus, in principle, be parsimoniously explained by a uniform female fertility insurance strategy.
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Affiliation(s)
- Oscar Vedder
- Institute of Avian Research, An der Vogelwarte 21, D-26386 Wilhelmshaven, Germany
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11
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Barrera-Guzmán AO, Aleixo A, Faccio M, de Melo Dantas S, Weir JT. Gene flow, genomic homogenization and the timeline to speciation in Amazonian manakins. Mol Ecol 2022; 31:4050-4066. [PMID: 35665558 DOI: 10.1111/mec.16562] [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: 10/29/2021] [Revised: 02/28/2022] [Accepted: 05/12/2022] [Indexed: 11/26/2022]
Abstract
Phylogeographic studies of the most species rich region of the planet - the Amazon basin - repeatedly uncover genetically distinctive, allopatric lineages within currently named species, but understanding whether such lineages are reproductively isolated species is challenging. Here we harness the power of genome-wide datasets together with detailed phylogeographic sampling to both characterize the number of unique lineages and infer levels of reproductive isolation for three parapatric manakin species that make up the genus Pipra. The mitochondrial and nuclear genomes both support six distinctive lineages. The youngest lineages are now highly admixed with each other across major portions of their geographic ranges with one lineage now extinct in a genomically unadmixed state. In contrast, the oldest sets of lineages - dated to 1.4 million years - exhibit narrow hybrid zones. By fitting demographic models to parapatric lineage pairs we found that levels of gene flow and genomic homogenization decline with increasing evolutionary age. Only lineages descending from the 1.4 Ma basal node in the genus experience negligible gene flow, possess genomes resistant to homogenization and are separated by narrow hybrid zones. We conclude that a million years or more were required for Pipra manakins to become reproductively isolated. We suggest the six lineages be reclassified as two or three reproductively isolated species. Our unique approach to quantifying reproductive isolation in parapatric lineages could be applied broadly to other phylogeographic studies and would help determine species classification of the plethora of newly identified lineages in the Amazon basin and other regions.
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Affiliation(s)
- Alfredo O Barrera-Guzmán
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada.,Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada.,Departamento de Biología Marina, Campus de Ciencias biológicas y Agropecuarias, Universidad Autónoma de Yucatán
| | - Alexandre Aleixo
- Pós-graduação em Biodiversidade e Evolução, Museu Paraense Emílio Goeldi, Belém, Brazil.,Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland
| | - Maya Faccio
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada.,Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Sidnei de Melo Dantas
- Pós-graduação em Biodiversidade e Evolução, Museu Paraense Emílio Goeldi, Belém, Brazil
| | - Jason T Weir
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada.,Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada.,Department of ornithology, Royal Ontario Museum, Toronto, Ontario, Canada
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12
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Sotelo-Muñoz M, Poignet M, Albrecht T, Kauzál O, Dedukh D, Schlebusch SA, Janko K, Reifová R. Germline-restricted chromosome shows remarkable variation in size among closely related passerine species. Chromosoma 2022; 131:77-86. [PMID: 35389062 DOI: 10.1007/s00412-022-00771-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 03/19/2022] [Accepted: 03/22/2022] [Indexed: 12/20/2022]
Abstract
Passerine birds have a supernumerary chromosome in their germ cells called the germline-restricted chromosome (GRC). The GRC was first discovered more than two decades ago in zebra finch but recent studies have suggested that it is likely present in all passerines, the most species rich avian order, encompassing more than half of all modern bird species. Despite its wide taxonomic distribution, studies on this chromosome are still scarce and limited to a few species. Here, we cytogenetically analyzed the GRC in five closely related estrildid finch species of the genus Lonchura. We show that the GRC varies enormously in size, ranging from a tiny micro-chromosome to one of the largest macro-chromosomes in the cell, not only among recently diverged species but also within species and sometimes even between germ cells of a single individual. In Lonchura atricapilla, we also observed variation in GRC copy number among male germ cells of a single individual. Finally, our analysis of hybrids between two Lonchura species with noticeably different GRC size directly supported maternal inheritance of the GRC. Our results reveal the extraordinarily dynamic nature of the GRC, which might be caused by frequent gains and losses of sequences on this chromosome leading to substantial differences in genetic composition of the GRC between and even within species. Such differences might theoretically contribute to reproductive isolation between species and thus accelerate the speciation rate of passerine birds compared to other bird lineages.
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Affiliation(s)
- Manuelita Sotelo-Muñoz
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, 12800, Prague, Czech Republic.
| | - Manon Poignet
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, 12800, Prague, Czech Republic
| | - Tomáš Albrecht
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, 12800, Prague, Czech Republic.,Institute of Vertebrate Biology, Czech Academy of Sciences, Květná 8, 60365, Brno, Czech Republic
| | - Ondřej Kauzál
- Institute of Vertebrate Biology, Czech Academy of Sciences, Květná 8, 60365, Brno, Czech Republic.,Department of Ecology, Faculty of Science, Charles University, Viničná 7, 12800, Prague, Czech Republic
| | - Dmitrij Dedukh
- Institute of Animal Physiology and Genetics, Czech Academy of Sciences, 27721, Liběchov, Czech Republic
| | - Stephen A Schlebusch
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, 12800, Prague, Czech Republic
| | - Karel Janko
- Institute of Animal Physiology and Genetics, Czech Academy of Sciences, 27721, Liběchov, Czech Republic.,Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Radka Reifová
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, 12800, Prague, Czech Republic.
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13
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Weyna A, Bourouina L, Galtier N, Romiguier J. Detection of F1 hybrids from single-genome data reveals frequent hybridization in Hymenoptera and particularly ants. Mol Biol Evol 2022; 39:6562163. [PMID: 35363317 PMCID: PMC9021736 DOI: 10.1093/molbev/msac071] [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] [Indexed: 11/14/2022] Open
Abstract
Hybridization occupies a central role in many fundamental evolutionary processes, such as speciation or adaptation. Yet, despite its pivotal importance in evolution, little is known about the actual prevalence and distribution of current hybridization across the tree of life. Here we develop and implement a new statistical method enabling the detection of F1 hybrids from single-individual genome sequencing data. Using simulations and sequencing data from known hybrid systems, we first demonstrate the specificity of the method, and identify its statistical limits. Next, we showcase the method by applying it to available sequencing data from more than 1,500 species of Arthropods, including Hymenoptera, Hemiptera, Coleoptera, Diptera, and Archnida. Among these taxa, we find Hymenoptera, and especially ants, to display the highest number of candidate F1 hybrids, suggesting higher rates of recent hybridization between previously isolated gene pools in these groups. The prevalence of F1 hybrids was heterogeneously distributed across ants, with taxa including many candidates tending to harbor specific ecological and life-history traits. This work shows how large-scale genomic comparative studies of recent hybridization can be implemented, uncovering the determinants of first-generation hybridization across whole taxa.
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Affiliation(s)
- Arthur Weyna
- Institut des Sciences de l'Evolution (UMR 5554), University of Montpellier, CNRS
| | - Lucille Bourouina
- Institut des Sciences de l'Evolution (UMR 5554), University of Montpellier, CNRS
| | - Nicolas Galtier
- Institut des Sciences de l'Evolution (UMR 5554), University of Montpellier, CNRS
| | - Jonathan Romiguier
- Institut des Sciences de l'Evolution (UMR 5554), University of Montpellier, CNRS
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14
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Grabenstein KC, Otter KA, Burg TM, Taylor SA. Sympatry leads to reduced body condition in chickadees that occasionally hybridize. Ecol Evol 2022; 12:e8756. [PMID: 35386870 PMCID: PMC8975787 DOI: 10.1002/ece3.8756] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 02/21/2022] [Accepted: 03/01/2022] [Indexed: 12/13/2022] Open
Abstract
Both abiotic and biotic drivers influence species distributions. Abiotic drivers such as climate have received considerable attention, even though biotic drivers such as hybridization often interact with abiotic drivers. We sought to explore the (1) costs of co‐occurrence for ecologically similar species that hybridize and (2) associations between ecological factors and condition to understand how abiotic and biotic factors influence species distributions. For two closely related and ecologically similar songbirds, black‐capped and mountain chickadees, we characterized body condition, as a proxy for fitness, using a 1358‐individual range‐wide dataset. We compared body condition in sympatry and allopatry with several abiotic and biotic factors using species‐specific generalized linear mixed models. We generated genomic data for a subset of 217 individuals to determine the extent of hybridization‐driven admixture in our dataset. Within this data subset, we found that ~11% of the chickadees had hybrid ancestry, and all hybrid individuals had typical black‐capped chickadee plumage. In the full dataset, we found that birds of both species, independent of demographic and abiotic factors, had significantly lower body condition when occurring in sympatry than birds in allopatry. This could be driven by either the inclusion of cryptic, likely poor condition, hybrids in our full dataset, competitive interactions in sympatry, or range edge effects. We are currently unable to discriminate between these mechanisms. Our findings have implications for mountain chickadees in particular, which will encounter more black‐capped chickadees as black‐capped chickadee ranges shift upslope and could lead to local declines in mountain chickadee populations.
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Affiliation(s)
- Kathryn C. Grabenstein
- Ecology and Evolutionary Biology University of Colorado at Boulder Boulder Colorado USA
| | - Ken A. Otter
- Natural Resources and Environmental Studies University of Northern British Columbia Prince George British Columbia Canada
| | | | - Scott A. Taylor
- Ecology and Evolutionary Biology University of Colorado at Boulder Boulder Colorado USA
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15
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Driver R, Ferretti V, Burton ES, McCoy MW, Duerr KC, Curry RL. Spatiotemporal variation in hatching success and nestling sex ratios track rapid movement of a songbird hybrid zone. Am Nat 2022; 200:264-274. [DOI: 10.1086/720207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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16
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Hybridization between Anguillicola crassus and A. novaezelandiae, and viability of the F1 generation. J Helminthol 2022; 96:e22. [PMID: 35300740 DOI: 10.1017/s0022149x22000104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
For decades, it has remained unclear how the Asian swim bladder nematode Anguillicola crassus was able to supplant the previously stable population of its relative from New Zealand Anguillicola novaezelandiae in the Lake Bracciano, Italy. Previously, researchers have hypothesized that A. crassus possesses an ecological advantage due to a more efficient life cycle in combination with a pattern of unidirectional hybridization between A. novaezelandiae females and A. crassus males. The present study focuses on the viability of hybrid offspring and their allelic pattern, particularly in developed adult stages of the hybrid F1 generation. While the percentages of hybrid individuals from A. novaezelandiae mothers and A. crassus fathers increased from egg to adult stages, it was more distinct in egg stages of A. crassus females and A. novaezelandiae males, but did not occur in adult F1 individuals at all. Therefore, we corroborate the hypothesis of unidirectional hybridization by differentiating between egg and adult stages, and suggest this as another explanatory factor for the extinction of A. novaezelandiae in Lake Bracciano in Italy and the predominance of A. crassus.
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17
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Brown JI, Harrigan RJ, Lavretsky P. Evolutionary and Ecological Drivers of Local Adaptation and Speciation in a North American Avian Species Complex. Mol Ecol 2022; 31:2578-2593. [PMID: 35263000 DOI: 10.1111/mec.16423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 01/31/2022] [Accepted: 02/28/2022] [Indexed: 11/26/2022]
Abstract
Throughout the speciation process, genomic divergence can be differentially impacted by selective pressures, as well as gene flow and genetic drift. Disentangling the effects of these evolutionary mechanisms remains challenging, especially for non-model organisms. Accounting for complex evolutionary histories and contemporary population structure often requires sufficient sample sizes, for which the expense of full genomes remains prohibitive. Here, we demonstrate the utility of partial-genome sequence data for range-wide samples to shed light into the divergence process of two closely related ducks, the Mexican duck (Anas diazi) and mallard (A. platyrhynchos). We determine the role of selective and neutral processes during speciation of Mexican ducks by integrating evolutionary and demographic modelling with genotype-environment and genotype-phenotype association testing. First, evolutionary models and demographic analyses support the hypothesis that Mexican ducks originally diverged ~300,000 years ago in a climate refugia arising during a glacial period in in a southwestern North America, and that subsequent environmental selective pressures played a key role in divergence. Mexican ducks then showed cyclical demographic patterns that likely reflected repeated range expansions and contractions, along with bouts of gene flow with mallards during glacial cycles. Finally, we provide evidence that sexual selection acted on several phenotypic traits as a co-evolutionary process, facilitating the development of reproductive barriers that initially arose due to strong ecological selection. More broadly, this work reveals that the genomic and phenotypic patterns observed across species complexes are the result of myriad factors that contribute in dynamic ways to the evolutionary trajectories of a lineage.
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Affiliation(s)
- Joshua I Brown
- Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, 79668, USA
| | - Ryan J Harrigan
- Center for Tropical Research, University of California, Los Angeles, La Kretz Hall, Suite 300, Los Angeles, CA, 90095, U.S.A
| | - Philip Lavretsky
- Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, 79668, USA
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18
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Ottenburghs J. Avian introgression patterns are consistent with Haldane's Rule. J Hered 2022; 113:363-370. [PMID: 35134952 PMCID: PMC9308041 DOI: 10.1093/jhered/esac005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 01/27/2022] [Indexed: 11/13/2022] Open
Abstract
According to Haldane’s Rule, the heterogametic sex will show the greatest fitness reduction in a hybrid cross. In birds, where sex is determined by a ZW system, female hybrids are expected to experience lower fitness compared to male hybrids. This pattern has indeed been observed in several bird groups, but it is unknown whether the generality of Haldane’s Rule also extends to the molecular level. First, given the lower fitness of female hybrids, we can expect maternally inherited loci (i.e., mitochondrial and W-linked loci) to show lower introgression rates than biparentally inherited loci (i.e., autosomal loci) in females. Second, the faster evolution of Z-linked loci compared to autosomal loci and the hemizygosity of the Z-chromosome in females might speed up the accumulation of incompatible alleles on this sex chromosome, resulting in lower introgression rates for Z-linked loci than for autosomal loci. I tested these expectations by conducting a literature review which focused on studies that directly quantified introgression rates for autosomal, sex-linked, and mitochondrial loci. Although most studies reported introgression rates in line with Haldane’s Rule, it remains important to validate these genetic patterns with estimates of hybrid fitness and supporting field observations to rule out alternative explanations. Genomic data provide exciting opportunities to obtain a more fine-grained picture of introgression rates across the genome, which can consequently be linked to ecological and behavioral observations, potentially leading to novel insights into the genetic mechanisms underpinning Haldane’s Rule.
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Affiliation(s)
- Jente Ottenburghs
- Wildlife Ecology and Conservation, Wageningen University & Research, Wageningen, The Netherlands.,Forest Ecology and Forest Management, Wageningen University & Research, Wageningen, The Netherlands
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19
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Singhal S, Derryberry GE, Bravo GA, Derryberry EP, Brumfield RT, Harvey MG. The dynamics of introgression across an avian radiation. Evol Lett 2021; 5:568-581. [PMID: 34917397 PMCID: PMC8645201 DOI: 10.1002/evl3.256] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 07/11/2021] [Accepted: 08/31/2021] [Indexed: 01/20/2023] Open
Abstract
Hybridization and resulting introgression can play both a destructive and a creative role in the evolution of diversity. Thus, characterizing when and where introgression is most likely to occur can help us understand the causes of diversification dynamics. Here, we examine the prevalence of and variation in introgression using phylogenomic data from a large (1300+ species), geographically widespread avian group, the suboscine birds. We first examine patterns of gene tree discordance across the geographic distribution of the entire clade. We then evaluate the signal of introgression in a subset of 206 species triads using Patterson's D‐statistic and test for associations between introgression signal and evolutionary, geographic, and environmental variables. We find that gene tree discordance varies across lineages and geographic regions. The signal of introgression is highest in cases where species occur in close geographic proximity and in regions with more dynamic climates since the Pleistocene. Our results highlight the potential of phylogenomic datasets for examining broad patterns of hybridization and suggest that the degree of introgression between diverging lineages might be predictable based on the setting in which they occur.
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Affiliation(s)
- Sonal Singhal
- Department of Biology California State University, Dominguez Hills Carson California 90747
| | - Graham E Derryberry
- Department of Ecology and Evolutionary Biology University of Tennessee Knoxville Tennessee 37996
| | - Gustavo A Bravo
- Department of Organismic and Evolutionary Biology Harvard University Cambridge Massachusetts 02138.,Museum of Comparative Zoology Harvard University Cambridge Massachusetts 02138
| | - Elizabeth P Derryberry
- Department of Ecology and Evolutionary Biology University of Tennessee Knoxville Tennessee 37996
| | - Robb T Brumfield
- Museum of Natural Science Louisiana State University Baton Rouge Louisiana 70803.,Department of Biological Sciences Louisiana State University Baton Rouge Louisiana 70803
| | - Michael G Harvey
- Department of Biological Sciences The University of Texas at El Paso El Paso Texas 79968.,Biodiversity Collections The University of Texas at El Paso El Paso Texas 79968
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20
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Justyn NM, Callaghan CT, Hill GE. A response to estimating hybridization in the wild using community science data: a path forward. Evolution 2021; 76:359-361. [PMID: 34705282 DOI: 10.1111/evo.14390] [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: 06/13/2021] [Revised: 08/17/2021] [Accepted: 09/01/2021] [Indexed: 11/27/2022]
Abstract
When working with a citizen science database like eBird, there are many possible ways to filter or subsample observations. Here, we discuss the potential biases and assumptions that surround different subsampling approaches or filtering that can be done to the eBird database. Restricting observations to species that are known to frequently hybridize, a specific time of the year, or a specific location, has the potential to greatly inflate the calculated per individual rate of hybridization. Such filtering also assumes that researchers know a birds' capacity to hybridize with all other species in its range, which we argue is an unfounded assumption. We ultimately conclude that a limited filtering approach is ideal when using a citizen science database to attempt to address a broad question such as: what is the per individual rate of hybridization across all of the bird species in the United States? This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Nicholas M Justyn
- Department of Biological Sciences, Auburn University, Auburn, Alabama, United States, 36849
| | - Corey T Callaghan
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstraße 4, Leipzig, 04103, Germany
| | - Geoffrey E Hill
- Department of Biological Sciences, Auburn University, Auburn, Alabama, United States, 36849
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21
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Tang Q, Burri R, Liu Y, Suh A, Sundev G, Heckel G, Schweizer M. Seasonal migration patterns and the maintenance of evolutionary diversity in a cryptic bird radiation. Mol Ecol 2021; 31:632-645. [PMID: 34674334 PMCID: PMC9298432 DOI: 10.1111/mec.16241] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 10/07/2021] [Accepted: 10/12/2021] [Indexed: 02/03/2023]
Abstract
Morphological differentiation associated with evolutionary diversification is often explained with adaptive benefits but the processes and mechanisms maintaining cryptic diversity are still poorly understood. Using genome‐wide data, we show here that the pale sand martin Riparia diluta in Central and East Asia consists of three genetically deeply differentiated lineages which vary only gradually in morphology but broadly reflect traditional taxonomy. We detected no signs of gene flow along the eastern edge of the Qinghai‐Tibetan plateau between lowland south‐eastern Chinese R. d. fohkienensis and high‐altitude R. d. tibetana. Largely different breeding and migration timing between these low and high altitude populations as indicated by phenology data suggests that allochrony might act as prezygotic isolation mechanism in the area where their ranges abut. Mongolian populations of R. d. tibetana, however, displayed signs of limited mixed ancestries with Central Asian R. d. diluta. Their ranges meet in the area of a well‐known avian migratory divide, where western lineages take a western migration route around the Qinghai‐Tibetan plateau to winter quarters in South Asia, and eastern lineages take an eastern route to Southeast Asia. This might also be the case between western R. d. diluta and eastern R. d. tibetana as indicated by differing wintering grounds. We hypothesize that hybrids might have nonoptimal intermediate migration routes and selection against them might restrict gene flow. Although further potential isolation mechanisms might exist in the pale sand martin, our study points towards contrasting migration behaviour as an important factor in maintaining evolutionary diversity under morphological stasis.
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Affiliation(s)
- Qindong Tang
- Institute of Ecology and Evolution, University of Bern, Bern, Switzerland.,Natural History Museum, Bern, Switzerland
| | - Reto Burri
- Schweizerische Vogelwarte, Sempach, Switzerland
| | - Yang Liu
- State Key Laboratory of Biocontrol, College of Ecology School of Life Science, Sun Yat-sen University, Guangzhou, China
| | - Alexander Suh
- School of Biological Sciences-Organisms and the Environment, University of East Anglia, Norwich, UK.,Department of Organismal Biology - Systematic Biology, Evolutionary Biology Centre (EBC), Uppsala University, Uppsala, Sweden
| | - Gombobaatar Sundev
- National University of Mongolia and Mongolian Ornithological Society, Ulaanbaatar, Mongolia
| | - Gerald Heckel
- Institute of Ecology and Evolution, University of Bern, Bern, Switzerland
| | - Manuel Schweizer
- Institute of Ecology and Evolution, University of Bern, Bern, Switzerland.,Natural History Museum, Bern, Switzerland
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22
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Sato Y, Fujiwara S, Egas M, Matsuda T, Gotoh T. Patterns of reproductive isolation in a haplodiploid mite, Amphitetranychus viennensis: prezygotic isolation, hybrid inviability and hybrid sterility. BMC Ecol Evol 2021; 21:177. [PMID: 34551724 PMCID: PMC8459536 DOI: 10.1186/s12862-021-01896-5] [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: 12/24/2020] [Accepted: 08/23/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Evolution of reproductive isolation is an important process, generating biodiversity and driving speciation. To better understand this process, it is necessary to investigate factors underlying reproductive isolation through various approaches but also in various taxa. Previous studies, mainly focusing on diploid animals, supported the prevalent view that reproductive barriers evolve gradually as a by-product of genetic changes accumulated by natural selection by showing a positive relationship between the degree of reproductive isolation and genetic distance. Haplodiploid animals are expected to generate additional insight into speciation, but few studies investigated the prevalent view in haplodiploid animals. In this study, we investigate whether the relationship also holds in a haplodiploid spider mite, Amphitetranychus viennensis (Zacher). RESULTS We sampled seven populations of the mite in the Palaearctic region, measured their genetic distance (mtDNA) and carried out cross experiments with all combinations. We analyzed how lack of fertilization rate (as measure of prezygotic isolation) as well as hybrid inviability and hybrid sterility (as measures of postzygotic isolation) varies with genetic distance. We found that the degree of reproductive isolation varies among cross combinations, and that all three measures of reproductive isolation have a positive relationship with genetic distance. Based on the mtDNA marker, lack of fertilization rate, hybrid female inviability and hybrid female sterility were estimated to be nearly complete (99.0-99.9% barrier) at genetic distances of 0.475-0.657, 0.150-0.209 and 0.145-0.210, respectively. Besides, we found asymmetries in reproductive isolation. CONCLUSIONS The prevalent view on the evolution of reproductive barriers is supported in the haplodiploid spider mite we studied here. According to the estimated minimum genetic distance for total reproductive isolation in parent population crosses in this study and previous work, a genetic distance of 0.15-0.21 in mtDNA (COI) appears required for speciation in spider mites. Variations and asymmetries in the degree of reproductive isolation highlight the importance of reinforcement of prezygotic reproductive isolation through incompatibility and the importance of cytonuclear interactions for reproductive isolation in haplodiploid spider mites.
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Affiliation(s)
- Yukie Sato
- Faculty of Life and Environmental Science/Mountain Science Center, University of Tsukuba, Ibaraki, 305-8577, Japan
| | - Satoshi Fujiwara
- Laboratory of Applied Entomology and Zoology, Faculty of Agriculture, Ibaraki University, Ami, Ibaraki, 300-0393, Japan
| | - Martijn Egas
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Tomoko Matsuda
- Laboratory of Applied Entomology and Zoology, Faculty of Agriculture, Ibaraki University, Ami, Ibaraki, 300-0393, Japan.,Nihon BioData Corporation, Kawasaki, Kanagawa, 213-0012, Japan
| | - Tetsuo Gotoh
- Laboratory of Applied Entomology and Zoology, Faculty of Agriculture, Ibaraki University, Ami, Ibaraki, 300-0393, Japan. .,Faculty of Economics, Ryutsu Keizai University, Ryugasaki, Ibaraki, 301-8555, Japan.
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23
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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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24
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Bemmels JB, Bramwell AC, Anderson SAS, Luzuriaga-Aveiga VE, Mikkelsen EK, Weir JT. Geographic contact drives increased reproductive isolation in two cryptic Empidonax flycatchers. Mol Ecol 2021; 30:4833-4844. [PMID: 34347907 DOI: 10.1111/mec.16105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 07/05/2021] [Accepted: 07/28/2021] [Indexed: 01/02/2023]
Abstract
Geographic contact between sister lineages often occurs near the final stages of speciation, but its role in speciation's completion remains debated. Reproductive isolation may be essentially complete prior to secondary contact. Alternatively, costly interactions between partially reproductively isolated species - such as maladaptive hybridization or competition for resources - may select for divergence, increasing reproductive isolation and driving speciation toward completion. Here, we use coalescent demographic modelling and whole-genome data sets to show that a period of contact and elevated hybridization between sympatric eastern North American populations of two cryptic bird species preceded a major increase in reproductive isolation between these populations within the last 10,000 years. In contrast, substantial introgression continues to the present in a western contact zone where geographic overlap is much narrower and probably of more recent origin. In the sympatric eastern region where reproductive isolation has increased, it is not accompanied by character displacement in key morphometric traits, plumage coloration, or ecological traits. While the precise trait and underlying mechanism driving increased reproductive isolation remains unknown, we discuss several possibilities and outline avenues for future research. Overall, our results highlight how demographic models can reveal the geographic context in which reproductive isolation was completed, and demonstrate how contact can accelerate the final stages of speciation.
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Affiliation(s)
- Jordan B Bemmels
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Ashley C Bramwell
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Sean A S Anderson
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Vanessa E Luzuriaga-Aveiga
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Else K Mikkelsen
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Jason T Weir
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada.,Department of Natural History, Royal Ontario Museum, Toronto, ON, Canada
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25
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Hill GE, Justyn NM. A response to Justen et al. 2020: Estimating hybridization rates in the wild: Easier said than done? Evolution 2021; 75:2145-2147. [PMID: 34101832 DOI: 10.1111/evo.14276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 04/27/2021] [Accepted: 05/19/2021] [Indexed: 12/01/2022]
Abstract
We consider four key challenges related to estimating per-individual rates of hybridization in wild birds: (1) what is the meaning of the term "hybrid"?, (2) the importance of distinguishing between shared DNA sequences and on-going hybridization between populations, (3) the perils of focusing exclusively on known hybrid zones, and (4) the implications of very low rates of per individual hybridization. Because our focus is on using phenotype to recognize hybrids, we define a hybrid as an individual with a phenotype that is intermediate between two parental species. We emphasize the value of quantifying the rate of between-species mating that is ongoing in current populations and distinguish this endeavor from estimates of gene flow between populations based on genomic analysis, which can reflect both current and ancient hybridization. We restate the importance of quantifying per individual rates of hybridization among all birds without prejudging which birds are presumed to engage in hybridization. And finally, we emphasize that evidence for strong prezygotic sorting is not necessarily evidence that mate choice is a driver of speciation.
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Affiliation(s)
- Geoffrey E Hill
- Biological Sciences, Auburn University, Auburn, Alabama, USA
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26
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Justen H, Kimmitt AA, Delmore KE. Estimating hybridization rates in the wild: Easier said than done? Evolution 2021; 75:2137-2144. [PMID: 32820532 DOI: 10.1111/evo.14082] [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: 06/05/2020] [Revised: 08/06/2020] [Accepted: 08/10/2020] [Indexed: 11/30/2022]
Abstract
Hybridization has important effects on the evolutionary trajectories of natural populations but estimates of this process in the wild and at the individual-level are lacking. Justyn et al. attempted to fill this gap using the citizen science database eBird but there are limitations to this approach. Here, we outline and directly test these limitations using literature searches, case studies, and a comparison between eBird and Birds of North America (BNA), a database that documents hybridization using the scientific literature. We use a hybrid zone between Lazuli and Indigo buntings to highlight the importance of considering geographic range when estimating rates of hybridization and two literature searches to show the importance of considering cryptic hybrids (those that cannot be identified using phenotypic traits) when quantifying these rates. We also use BNA and a case study of hybrid White-faced and Glossy Ibises to show that citizen scientists are underreporting hybrids compared with experts. Justyn et al. highlighted an important gap in the literature, but their results likely represent the lower limit of hybridization between birds and a more nuanced interpretation of their results (e.g., considering extrinsic postzygotic selection) is needed.
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Affiliation(s)
- Hannah Justen
- Department of Biology, Texas A&M University, College Station, Texas
| | | | - Kira E Delmore
- Department of Biology, Texas A&M University, College Station, Texas
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27
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Russell T, Cullingham C, Ball M, Pybus M, Coltman D. Extent and direction of introgressive hybridization of mule and white-tailed deer in western Canada. Evol Appl 2021; 14:1914-1925. [PMID: 34295372 PMCID: PMC8288014 DOI: 10.1111/eva.13250] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 05/02/2021] [Indexed: 01/05/2023] Open
Abstract
Hybridization of mule deer (Odocoileus hemionus) and white-tailed deer (O. virginianus) appears to be a semi-regular occurrence in western North America. Previous studies confirmed the presence of hybrids in a variety of sympatric habitats, but their developing molecular resources limited identification to the earliest, most admixed generations. For this reason, estimates of hybrid production in wild populations often rely on anecdotal reports. As well, white-tailed deer populations' continued encroachment into historically mule deer-occupied habitats due to changes in land use, habitat homogenization, and a warming climate may increase opportunities for interspecific encounters. We sought to quantify the prevalence and extent of hybrid deer in the prairies of western Canada using a SNP assay with enhanced discriminating power. By updating the available molecular resources, we sought to identify and characterize previously cryptic introgression. We also investigated the influence of various parameters on hybridity by way of logistic regression. We observed overall hybridization rates of ~1.0%, slightly lower than that reported by previous studies, and found white-tailed-like hybrids to be more common than their mule deer-like counterparts. Here, we build upon past studies of hybridization in North American deer by increasing hybrid detection power, expanding sample sizes, demonstrating a new molecular resource applicable to future research and observing asymmetrical directionality of introgression.
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Affiliation(s)
- Ty Russell
- Department of Biological SciencesUniversity of AlbertaEdmontonCanada
- Present address:
LGL Limited Environmental Research AssociatesSidneyCanada
| | | | - Mark Ball
- Alberta Fish and WildlifeEdmontonCanada
| | | | - David Coltman
- Department of Biological SciencesUniversity of AlbertaEdmontonCanada
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28
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Lopez KA, McDiarmid CS, Griffith SC, Lovette IJ, Hooper DM. Evaluating evidence of mitonuclear incompatibilities with the sex chromosomes in an avian hybrid zone. Evolution 2021; 75:1395-1414. [PMID: 33908624 DOI: 10.1111/evo.14243] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 02/15/2021] [Accepted: 04/11/2021] [Indexed: 12/13/2022]
Abstract
The exploration of hybrid zones and the intergenomic conflicts exposed through hybridization provide windows into the processes of divergence and speciation. Sex chromosomes and mitonuclear incompatibilities have strong associations with the genetics of hybrid dysfunction. In ZW sex-determining systems, maternal co-inheritance of the mitochondrial and W chromosomes immediately exposes incompatibilities between these maternal contributions of one species and the Z chromosome of another. We analyze mitochondrial and Z chromosome admixture in the long-tailed finch (Poephila acuticauda) of Australia, where hybridizing subspecies differ prominently in Z chromosome genotype and in bill color, yet the respective centers of geographic admixture for these two traits are offset by 350 km. We report two well-defined mitochondrial clades that diverged ∼0.5 million years ago. Mitochondrial contact is geographically co-located within a hybrid zone of Z chromosome admixture and is displaced from bill color admixture by nearly 400 km. Consistent with Haldane's rule expectations, hybrid zone females are significantly less likely than males to carry an admixed Z chromosome or have mismatched Z-mitochondrial genotypes. Furthermore, there are significantly fewer than expected mitonuclear mismatches in hybrid zone females and paternal backcross males. Results suggest a potential for mitonuclear/sex chromosome incompatibilities in the emergence of reproductive isolation in this system.
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Affiliation(s)
- Kelsie A Lopez
- Cornell Lab of Ornithology, Cornell University, Ithaca, NY, 14850, USA
| | - Callum S McDiarmid
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Simon C Griffith
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Irby J Lovette
- Cornell Lab of Ornithology, Cornell University, Ithaca, NY, 14850, USA
| | - Daniel M Hooper
- Cornell Lab of Ornithology, Cornell University, Ithaca, NY, 14850, USA.,Department of Biological Sciences, Columbia University, New York, NY, 10027, USA
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29
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Stankowski S, Ravinet M. Defining the speciation continuum. Evolution 2021; 75:1256-1273. [PMID: 33754340 DOI: 10.1111/evo.14215] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 03/01/2021] [Accepted: 03/13/2021] [Indexed: 02/06/2023]
Abstract
A primary roadblock to our understanding of speciation is that it usually occurs over a timeframe that is too long to study from start to finish. The idea of a speciation continuum provides something of a solution to this problem; rather than observing the entire process, we can simply reconstruct it from the multitude of speciation events that surround us. But what do we really mean when we talk about the speciation continuum, and can it really help us understand speciation? We explored these questions using a literature review and online survey of speciation researchers. Although most researchers were familiar with the concept and thought it was useful, our survey revealed extensive disagreement about what the speciation continuum actually tells us. This is due partly to the lack of a clear definition. Here, we provide an explicit definition that is compatible with the Biological Species Concept. That is, the speciation continuum is a continuum of reproductive isolation. After outlining the logic of the definition in light of alternatives, we explain why attempts to reconstruct the speciation process from present-day populations will ultimately fail. We then outline how we think the speciation continuum concept can continue to act as a foundation for understanding the continuum of reproductive isolation that surrounds us.
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Affiliation(s)
- Sean Stankowski
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom.,Current Address: Sean Stankowski, IST Austria, Klosterneuburg, 3400, Austria
| | - Mark Ravinet
- Centre for Ecological and Evolutionary Synthesis, University of Oslo, Oslo, 0316, Norway.,School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
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30
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Sianta SA, Kay KM. Parallel evolution of phenological isolation across the speciation continuum in serpentine-adapted annual wildflowers. Proc Biol Sci 2021; 288:20203076. [PMID: 33849321 PMCID: PMC8059516 DOI: 10.1098/rspb.2020.3076] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 03/17/2021] [Indexed: 01/26/2023] Open
Abstract
Understanding the relative importance of reproductive isolating mechanisms across the speciation continuum remains an outstanding challenge in evolutionary biology. Here, we examine a common isolating mechanism, reproductive phenology, between plant sister taxa at different stages of adaptive divergence to gain insight into its relative importance during speciation. We study 17 plant taxa that have independently adapted to inhospitable serpentine soils, and contrast each with a nonserpentine sister taxon to form pairs at either ecotypic or species-level divergence. We use greenhouse-based reciprocal transplants in field soils to quantify how often flowering time (FT) shifts accompany serpentine adaptation, when FT shifts evolve during speciation, and the genetic versus plastic basis of these shifts. We find that genetically based shifts in FT in serpentine-adapted taxa are pervasive regardless of the stage of divergence. Although plasticity increases FT shifts in five of the pairs, the degree of plasticity does not differ when comparing ecotypic versus species-level divergence. FT shifts generally led to significant, but incomplete, reproductive isolation that did not vary in strength by stage of divergence. Our work shows that adaptation to a novel habitat may predictably drive phenological isolation early in the speciation process.
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Affiliation(s)
- Shelley A. Sianta
- Department of Ecology and Evolutionary Biology, University of California, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | - Kathleen M. Kay
- Department of Ecology and Evolutionary Biology, University of California, 130 McAllister Way, Santa Cruz, CA 95060, USA
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31
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Turbek SP, Browne M, Di Giacomo AS, Kopuchian C, Hochachka WM, Estalles C, Lijtmaer DA, Tubaro PL, Silveira LF, Lovette IJ, Safran RJ, Taylor SA, Campagna L. Rapid speciation via the evolution of pre-mating isolation in the Iberá Seedeater. Science 2021; 371:371/6536/eabc0256. [PMID: 33766854 DOI: 10.1126/science.abc0256] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 01/21/2021] [Indexed: 12/20/2022]
Abstract
Behavioral isolation can catalyze speciation and permit the slow accumulation of additional reproductive barriers between co-occurring organisms. We illustrate how this process occurs by examining the genomic and behavioral bases of pre-mating isolation between two bird species (Sporophila hypoxantha and the recently discovered S. iberaensis) that belong to the southern capuchino seedeaters, a recent, rapid radiation characterized by variation in male plumage coloration and song. Although these two species co-occur without obvious ecological barriers to reproduction, we document behaviors indicating species recognition by song and plumage traits and strong assortative mating associated with genomic regions underlying male plumage patterning. Plumage differentiation likely originated through the reassembly of standing genetic variation, indicating how novel sexual signals may quickly arise and maintain species boundaries.
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Affiliation(s)
- Sheela P Turbek
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA.
| | - Melanie Browne
- Centro de Ecología Aplicada del Litoral (CECOAL, CONICET), Corrientes, Argentina
| | - Adrián S Di Giacomo
- Centro de Ecología Aplicada del Litoral (CECOAL, CONICET), Corrientes, Argentina
| | - Cecilia Kopuchian
- Centro de Ecología Aplicada del Litoral (CECOAL, CONICET), Corrientes, Argentina
| | - Wesley M Hochachka
- Center for Avian Population Studies, Cornell Lab of Ornithology, Ithaca, NY, USA
| | - Cecilia Estalles
- Museo Argentino de Ciencias Naturales Bernardino Rivadavia (MACN, CONICET), Buenos Aires, Argentina
| | - Darío A Lijtmaer
- Museo Argentino de Ciencias Naturales Bernardino Rivadavia (MACN, CONICET), Buenos Aires, Argentina
| | - Pablo L Tubaro
- Museo Argentino de Ciencias Naturales Bernardino Rivadavia (MACN, CONICET), Buenos Aires, Argentina
| | | | - Irby J Lovette
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA.,Fuller Evolutionary Biology Program, Cornell Lab of Ornithology, Ithaca, NY, USA
| | - Rebecca J Safran
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Scott A Taylor
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Leonardo Campagna
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA. .,Fuller Evolutionary Biology Program, Cornell Lab of Ornithology, Ithaca, NY, USA
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32
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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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33
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Leighton GM, Lu LJ, Holop E, Dobler J, Ligon RA. Sociality and migration predict hybridization across birds. Proc Biol Sci 2021; 288:20201946. [PMID: 33726589 DOI: 10.1098/rspb.2020.1946] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Hybridization represents a natural experiment that can provide insight into processes of speciation and diversification. Though considerable research has focused on hybrid zone dynamics, macroevolutionary investigations of the factors that influence hybridization are few. Here, we compile a database of avian hybrids and perform comparative analyses to determine whether several social and life-history variables influence broad patterns of hybridization. We perform three main analyses: phylogenetic logistic regression to examine variables that are associated with the presence of hybridization, phylogenetic Poisson regression of only those species exhibiting hybridization to determine which variables are associated with the extent of hybridization, and a phylogenetic logistic regression on a subset of data to assess potential pseudoreplication. After testing several social and life-history variables, we found that social bond duration is associated with the presence and extent of hybridization. Specifically, lengthy social bonds are negatively associated with the presence and extent of hybridization. In addition to social bond length, migration is positively linked with a greater likelihood of hybridization. The broad-scale correlations between species-specific traits and hybridization across diverse avian lineages suggest commonalities in the fine-scale processes involved in mating with heterospecifics, which in turn has implications for how we think about, study and understand hybridization processes and their influence on evolutionary trajectories.
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Affiliation(s)
- Gavin M Leighton
- Department of Biology, SUNY Buffalo State College, Buffalo, NY 14213, USA.,Department of Neurobiology & Behavior, Cornell Lab of Ornithology, Cornell University, 215 Tower Road, Ithaca, NY 14850, USA
| | - Lucy Jingyi Lu
- Department of Neurobiology & Behavior, Cornell Lab of Ornithology, Cornell University, 215 Tower Road, Ithaca, NY 14850, USA
| | - Eliot Holop
- Department of Neurobiology & Behavior, Cornell Lab of Ornithology, Cornell University, 215 Tower Road, Ithaca, NY 14850, USA
| | - Jessica Dobler
- Department of Neurobiology & Behavior, Cornell Lab of Ornithology, Cornell University, 215 Tower Road, Ithaca, NY 14850, USA
| | - Russell A Ligon
- Department of Neurobiology & Behavior, Cornell Lab of Ornithology, Cornell University, 215 Tower Road, Ithaca, NY 14850, USA
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34
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Lavretsky P, Wilson RE, Talbot SL, Sonsthagen SA. Phylogenomics reveals ancient and contemporary gene flow contributing to the evolutionary history of sea ducks (Tribe Mergini). Mol Phylogenet Evol 2021; 161:107164. [PMID: 33798675 DOI: 10.1016/j.ympev.2021.107164] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 02/05/2021] [Accepted: 03/25/2021] [Indexed: 12/26/2022]
Abstract
Insight into complex evolutionary histories continues to build through broad comparative phylogenomic and population genomic studies. In particular, there is a need to understand the extent and scale that gene flow contributes to standing genomic diversity and the role introgression has played in evolutionary processes such as hybrid speciation. Here, we investigate the evolutionary history of the Mergini tribe (sea ducks) by coupling multi-species comparisons with phylogenomic analyses of thousands of nuclear ddRAD-seq loci, including Z-sex chromosome and autosomal linked loci, and the mitogenome assayed across all extant sea duck species in North America. All sea duck species are strongly structured across all sampled marker types (pair-wise species ΦST > 0.2), with clear genetic assignments of individuals to their respective species, and phylogenetic relationships recapitulate known relationships. Despite strong species integrity, we identify at least 18 putative hybrids; with all but one being late generational backcrosses. Most interesting, we provide the first evidence that an ancestral gene flow event between long-tailed ducks (Clangula hyemalis) and true Eiders (Somateria spp.) not only moved genetic material into the former species, but likely generated a novel species - the Steller's eider (Polysticta stelleri) - via hybrid speciation. Despite generally low contemporary levels of gene flow, we conclude that hybridization has and continues to be an important process that shifts novel genetic variation between species within the tribe Mergini. Finally, we outline methods that permit researchers to contrast genomic patterns of contemporary versus ancestral gene flow when attempting to reconstruct potentially complex evolutionary histories.
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Affiliation(s)
- Philip Lavretsky
- Department of Biological Sciences, University of Texas at El Paso, El Paso, TX 79668, USA; US Geological Survey, Alaska Science Center, 4210 University Dr., Anchorage, AK 99508, USA.
| | - Robert E Wilson
- US Geological Survey, Alaska Science Center, 4210 University Dr., Anchorage, AK 99508, USA
| | - Sandra L Talbot
- US Geological Survey, Alaska Science Center, 4210 University Dr., Anchorage, AK 99508, USA
| | - Sarah A Sonsthagen
- US Geological Survey, Alaska Science Center, 4210 University Dr., Anchorage, AK 99508, USA
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35
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Seifert B. The Gene and Gene Expression (GAGE) Species Concept: An Universal Approach for All Eukaryotic Organisms. Syst Biol 2021; 69:1033-1038. [PMID: 32298447 DOI: 10.1093/sysbio/syaa032] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 03/20/2020] [Accepted: 04/07/2020] [Indexed: 12/31/2022] Open
Abstract
The Gene and Gene Expression (GAGE) species concept, a new version of the Pragmatic Species Concept of Seifert (2014), is proposed as a concept applicable to any described recent or fossil eukaryotic organism independent from its mode of reproduction or evolutionary history. In addition to presenting the concept as such, the article also provides practical recommendations for taxonomists when delimiting species and describing taxa. The wording of the new concept contains a heading core sentence plus five attached sentences addressing essential conditions for its translation into a sound taxonomic practice: "Species are separable clusters that have passed a threshold of evolutionary divergence and are exclusively defined by nuclear DNA sequences and/or their expression products. Nuclear DNA sequences and their expression products are different character systems but have a highly correlated indicative function. Character systems with the least risk of epigenetic or ontogenetic modification have superior indicative value when conflicts between character systems of integrative studies arise. All character systems have to be described by an adequate numerics allowing cluster formation and determination of thresholds. Thresholds for each character system should be fixed by consensus among the experts under the principle of avoiding oversplitting or lumping. Clusters must not be the expression of intraspecific polymorphism." Recognizing the distortions and conflicts caused to taxonomy through barcoding or through assessment on the basis of association with other organisms, the GAGE species concept strongly downgrades the use of cytoplasmic DNA of endosymbiotic origin (mtDNA, cpDNA) or DNA of closely associated microbes (e.g., Wolbachia bacteria) for final taxonomic decision-making. Recognizing the distortion of phylogenies by the high frequency of reticulate evolution, it is argued that delimiting and naming species has to be separated from constructing bifurcating phylogenetic trees. [Cytoplasmic DNA; lumping; nuclear DNA; numeric taxonomy; oversplitting; reticulate evolution.].
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Affiliation(s)
- Bernhard Seifert
- Department of Zoology, Senckenberg Museum of Natural History Görlitz, Am Museum 1, D-02826 Görlitz, Germany
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36
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Schneemann H, De Sanctis B, Roze D, Bierne N, Welch JJ. The geometry and genetics of hybridization. Evolution 2020; 74:2575-2590. [PMID: 33150956 PMCID: PMC7839769 DOI: 10.1111/evo.14116] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 07/26/2020] [Accepted: 10/12/2020] [Indexed: 11/30/2022]
Abstract
When divergent populations form hybrids, hybrid fitness can vary with genome composition, current environmental conditions, and the divergence history of the populations. We develop analytical predictions for hybrid fitness, which incorporate all three factors. The predictions are based on Fisher's geometric model, and apply to a wide range of population genetic parameter regimes and divergence conditions, including allopatry and parapatry, local adaptation, and drift. Results show that hybrid fitness can be decomposed into intrinsic effects of admixture and heterozygosity, and extrinsic effects of the (local) adaptedness of the parental lines. Effect sizes are determined by a handful of geometric distances, which have a simple biological interpretation. These distances also reflect the mode and amount of divergence, such that there is convergence toward a characteristic pattern of intrinsic isolation. We next connect our results to the quantitative genetics of line crosses in variable or patchy environments. This means that the geometrical distances can be estimated from cross data, and provides a simple interpretation of the "composite effects." Finally, we develop extensions to the model, involving selectively induced disequilibria, and variable phenotypic dominance. The geometry of fitness landscapes provides a unifying framework for understanding speciation, and wider patterns of hybrid fitness.
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Affiliation(s)
- Hilde Schneemann
- Department of GeneticsUniversity of CambridgeDowning StreetCambridgeUnited Kingdom
- Institut des Sciences de l'ÉvolutionUniversité MontpellierUMR 5554, Montpellier Cedex 05France
| | - Bianca De Sanctis
- Department of GeneticsUniversity of CambridgeDowning StreetCambridgeUnited Kingdom
- Department of ZoologyUniversity of CambridgeDowning StreetCambridgeUnited Kingdom
| | - Denis Roze
- CNRS, UMI 3614Evolutionary Biology and Ecology of AlgaeRoscoffFrance
- Station Biologique de RoscoffSorbonne UniversitéRoscoff29688France
| | - Nicolas Bierne
- ISEM Université Montpellier, CNRS, EPHE, IRDMontpellierFrance
| | - John J. Welch
- Department of GeneticsUniversity of CambridgeDowning StreetCambridgeUnited Kingdom
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37
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Tobias JA, Ottenburghs J, Pigot AL. Avian Diversity: Speciation, Macroevolution, and Ecological Function. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2020. [DOI: 10.1146/annurev-ecolsys-110218-025023] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The origin, distribution, and function of biological diversity are fundamental themes of ecology and evolutionary biology. Research on birds has played a major role in the history and development of these ideas, yet progress was for many decades limited by a focus on patterns of current diversity, often restricted to particular clades or regions. Deeper insight is now emerging from a recent wave of integrative studies combining comprehensive phylogenetic, environmental, and functional trait data at unprecedented scales. We review these empirical advances and describe how they are reshaping our understanding of global patterns of bird diversity and the processes by which it arises, with implications for avian biogeography and functional ecology. Further expansion and integration of data sets may help to resolve longstanding debates about the evolutionary origins of biodiversity and offer a framework for understanding and predicting the response of ecosystems to environmental change.
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Affiliation(s)
- Joseph A. Tobias
- Department of Life Sciences, Imperial College London, Silwood Park, Ascot SL5 7PY, United Kingdom
| | - Jente Ottenburghs
- Department of Evolutionary Biology, Uppsala University, 752 36 Uppsala, Sweden
| | - Alex L. Pigot
- Centre for Biodiversity and Environment Research, Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, United Kingdom
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38
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Gainsford A, Jones GP, Hobbs JA, Heindler FM, van Herwerden L. Species integrity, introgression, and genetic variation across a coral reef fish hybrid zone. Ecol Evol 2020; 10:11998-12014. [PMID: 33209265 PMCID: PMC7663085 DOI: 10.1002/ece3.6769] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 07/16/2020] [Accepted: 07/17/2020] [Indexed: 11/10/2022] Open
Abstract
Hybridization and introgression are evolutionarily significant phenomena breaking down species boundaries. "Hybrid zones" (regions of species overlap and hybridization) enable quantification of hybridization frequency and examination of mechanisms driving and maintaining gene flow. The hybrid anemonefish Amphiprion leucokranos is found where parent species (A. chrysopterus; A. sandaracinos) distributions overlap. Here, we examine geographic variation in hybridization and introgression, and potential impacts on parent species integrity through assessing relative abundance, social group composition, and genetic structure (mtDNA cytochrome b, 21 microsatellite loci) of taxa at three hybrid zone locations: Kimbe Bay (KB) and Kavieng (KA), Papua New Guinea; the Solomon Islands (SO). Relative abundances of and size disparities between parent species apparently drive hybridization frequency, introgression patterns, and genetic composition of taxa. Conspecific groups are most common in KB (65%) where parent species are similarly abundant. Conversely, mixed species groups dominate SO (82%), where A. chrysopterus is more abundant. Hybrids most commonly cohabit with A. sandaracinos in KB (17%), but with A. chrysopterus in KA (22%) and SO (50%). Genetic differentiation (nDNA) analyses indicate that parent species remain distinct, despite ongoing hybridization and hybrids are genetically similar to A. sandaracinos-resulting from persistent backcrossing with this smallest species. This study shows that hybridization outcomes may depend on the social and ecological context in which taxa hybridize, where relative abundance and disparate size of parent species explain the frequency and patterns of hybridization and introgression in the A. leucokranos hybrid zone, reflecting size-based dominance behaviors of anemonefish social groups.
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Affiliation(s)
- Ashton Gainsford
- ARC Centre of Excellence for Coral Reef StudiesJames Cook UniversityTownsvilleQLDAustralia
- Faculty of Science and EngineeringJames Cook UniversityTownsvilleAustraliaAustralia
| | - Geoffrey P. Jones
- ARC Centre of Excellence for Coral Reef StudiesJames Cook UniversityTownsvilleQLDAustralia
- Faculty of Science and EngineeringJames Cook UniversityTownsvilleAustraliaAustralia
| | - Jean‐Paul A. Hobbs
- School of Biological SciencesThe University of QueenslandBrisbaneQLDAustralia
| | | | - Lynne van Herwerden
- Faculty of Science and EngineeringJames Cook UniversityTownsvilleAustraliaAustralia
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39
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Ishishita S, Tatsumoto S, Kinoshita K, Nunome M, Suzuki T, Go Y, Matsuda Y. Transcriptome analysis revealed misregulated gene expression in blastoderms of interspecific chicken and Japanese quail F1 hybrids. PLoS One 2020; 15:e0240183. [PMID: 33044996 PMCID: PMC7549780 DOI: 10.1371/journal.pone.0240183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 09/22/2020] [Indexed: 11/29/2022] Open
Abstract
Hybrid incompatibility, such as sterility and inviability, prevents gene flow between closely-related populations as a reproductive isolation barrier. F1 hybrids between chickens and Japanese quail (hereafter, referred to as quail), exhibit a high frequency of developmental arrest at the preprimitive streak stage. To investigate the molecular basis of the developmental arrest at the preprimitive streak stage in chicken–quail F1 hybrid embryos, we investigated chromosomal abnormalities in the hybrid embryos using molecular cytogenetic analysis. In addition, we quantified gene expression in parental species and chicken- and quail-derived allele-specific expression in the hybrids at the early blastoderm and preprimitive streak stages by mRNA sequencing. Subsequently, we compared the directions of change in gene expression, including upregulation, downregulation, or no change, from the early blastoderm stage to the preprimitive streak stage between parental species and their hybrids. Chromosome analysis revealed that the cells of the hybrid embryos contained a fifty-fifty mixture of parental chromosomes, and numerical chromosomal abnormalities were hardly observed in the hybrid cells. Gene expression analysis revealed that a part of the genes that were upregulated from the early blastoderm stage to the preprimitive streak stage in both parental species exhibited no upregulation of both chicken- and quail-derived alleles in the hybrids. GO term enrichment analysis revealed that these misregulated genes are involved in various biological processes, including ribosome-mediated protein synthesis and cell proliferation. Furthermore, the misregulated genes included genes involved in early embryonic development, such as primitive streak formation and gastrulation. These results suggest that numerical chromosomal abnormalities due to a segregation failure does not cause the lethality of chicken–quail hybrid embryos, and that the downregulated expression of the genes that are involved in various biological processes, including translation and primitive streak formation, mainly causes the developmental arrest at the preprimitive streak stage in the hybrids.
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Affiliation(s)
- Satoshi Ishishita
- Avian Bioscience Research Center, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, Japan
| | - Shoji Tatsumoto
- Cognitive Genomics Research Group, Exploratory Research Center on Life and Living Systems (ExCELLs), National Institutes of Natural Sciences, Okazaki, Aichi, Japan
| | - Keiji Kinoshita
- Avian Bioscience Research Center, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, Japan
| | - Mitsuo Nunome
- Avian Bioscience Research Center, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, Japan
| | - Takayuki Suzuki
- Avian Bioscience Research Center, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, Japan
- Laboratory of Avian Bioscience, Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, Japan
| | - Yasuhiro Go
- Cognitive Genomics Research Group, Exploratory Research Center on Life and Living Systems (ExCELLs), National Institutes of Natural Sciences, Okazaki, Aichi, Japan
| | - Yoichi Matsuda
- Avian Bioscience Research Center, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, Japan
- Laboratory of Avian Bioscience, Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, Japan
- * E-mail:
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40
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Coughlan JM, Matute DR. The importance of intrinsic postzygotic barriers throughout the speciation process. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190533. [PMID: 32654642 DOI: 10.1098/rstb.2019.0533] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Intrinsic postzygotic barriers can play an important and multifaceted role in speciation, but their contribution is often thought to be reserved to the final stages of the speciation process. Here, we review how intrinsic postzygotic barriers can contribute to speciation, and how this role may change through time. We outline three major contributions of intrinsic postzygotic barriers to speciation. (i) reduction of gene flow: intrinsic postzygotic barriers can effectively reduce gene exchange between sympatric species pairs. We discuss the factors that influence how effective incompatibilities are in limiting gene flow. (ii) early onset of species boundaries via rapid evolution: intrinsic postzygotic barriers can evolve between recently diverged populations or incipient species, thereby influencing speciation relatively early in the process. We discuss why the early origination of incompatibilities is expected under some biological models, and detail how other (and often less obvious) incompatibilities may also serve as important barriers early on in speciation. (iii) reinforcement: intrinsic postzygotic barriers can promote the evolution of subsequent reproductive isolation through processes such as reinforcement, even between relatively recently diverged species pairs. We incorporate classic and recent empirical and theoretical work to explore these three facets of intrinsic postzygotic barriers, and provide our thoughts on recent challenges and areas in the field in which progress can be made. This article is part of the theme issue 'Towards the completion of speciation: the evolution of reproductive isolation beyond the first barriers'.
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Affiliation(s)
- Jenn M Coughlan
- Department of Biology, University of North Carolina, 120 South Road, Coker Hall, Chapel Hill, NC 27599, USA
| | - Daniel R Matute
- Department of Biology, University of North Carolina, 120 South Road, Coker Hall, Chapel Hill, NC 27599, USA
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41
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Allen R, Ryan H, Davis BW, King C, Frantz L, Irving-Pease E, Barnett R, Linderholm A, Loog L, Haile J, Lebrasseur O, White M, Kitchener AC, Murphy WJ, Larson G. A mitochondrial genetic divergence proxy predicts the reproductive compatibility of mammalian hybrids. Proc Biol Sci 2020; 287:20200690. [PMID: 32486979 PMCID: PMC7341909 DOI: 10.1098/rspb.2020.0690] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 05/06/2020] [Indexed: 12/14/2022] Open
Abstract
Numerous pairs of evolutionarily divergent mammalian species have been shown to produce hybrid offspring. In some cases, F1 hybrids are able to produce F2s through matings with F1s. In other instances, the hybrids are only able to produce offspring themselves through backcrosses with a parent species owing to unisexual sterility (Haldane's Rule). Here, we explicitly tested whether genetic distance, computed from mitochondrial and nuclear genes, can be used as a proxy to predict the relative fertility of the hybrid offspring resulting from matings between species of terrestrial mammals. We assessed the proxy's predictive power using a well-characterized felid hybrid system, and applied it to modern and ancient hominins. Our results revealed a small overlap in mitochondrial genetic distance values that distinguish species pairs whose calculated distances fall within two categories: those whose hybrid offspring follow Haldane's Rule, and those whose hybrid F1 offspring can produce F2s. The strong correlation between genetic distance and hybrid fertility demonstrated here suggests that this proxy can be employed to predict whether the hybrid offspring of two mammalian species will follow Haldane's Rule.
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Affiliation(s)
- Richard Allen
- Palaeogenomics and Bio-Archaeology Research Network, Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford OX1 3QY, UK
| | - Hannah Ryan
- Palaeogenomics and Bio-Archaeology Research Network, Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford OX1 3QY, UK
| | - Brian W. Davis
- Veterinary Integrative Biosciences, Texas A&M University, College Station, TX 77843, USA
| | - Charlotte King
- Department of Archaeology, Durham University, Science Site, Durham DH1 3LE, UK
- Department of Anatomy, University of Otago, Great King Street, Dunedin 9016, New Zealand
| | - Laurent Frantz
- Palaeogenomics and Bio-Archaeology Research Network, Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford OX1 3QY, UK
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Evan Irving-Pease
- Palaeogenomics and Bio-Archaeology Research Network, Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford OX1 3QY, UK
- Lundbeck GeoGenetics Centre, The Globe Institute, University of Copenhagen, 1350 Copenhagen, Denmark
| | - Ross Barnett
- Palaeogenomics and Bio-Archaeology Research Network, Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford OX1 3QY, UK
| | - Anna Linderholm
- Palaeogenomics and Bio-Archaeology Research Network, Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford OX1 3QY, UK
- Department of Anthropology, Texas A&M University, College Station, TX 77843-4352, USA
| | - Liisa Loog
- Palaeogenomics and Bio-Archaeology Research Network, Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford OX1 3QY, UK
- Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK
| | - James Haile
- Palaeogenomics and Bio-Archaeology Research Network, Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford OX1 3QY, UK
| | - Ophélie Lebrasseur
- Palaeogenomics and Bio-Archaeology Research Network, Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford OX1 3QY, UK
- Department of Archaeology, Classics and Egyptology, University of Liverpool, 12-14 Abercromby Square, Liverpool L69 7WZ, UK
| | - Mark White
- Department of Archaeology, Durham University, Science Site, Durham DH1 3LE, UK
| | - Andrew C. Kitchener
- Department of Natural Sciences, National Museums Scotland, Chambers Street, Edinburgh EH1 IJF, UK
- Institute of Geography, School of Geosciences, University of Edinburgh, Drummond Street, Edinburgh EH9 3PX, UK
| | - William J. Murphy
- Veterinary Integrative Biosciences, Texas A&M University, College Station, TX 77843, USA
| | - Greger Larson
- Palaeogenomics and Bio-Archaeology Research Network, Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford OX1 3QY, UK
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42
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Irwin DE. Assortative Mating in Hybrid Zones Is Remarkably Ineffective in Promoting Speciation. Am Nat 2020; 195:E150-E167. [DOI: 10.1086/708529] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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43
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Hudson EJ, Creanza N, Shizuka D. The Role of Nestling Acoustic Experience in Song Discrimination in a Sparrow. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00099] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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44
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Justyn NM, Callaghan CT, Hill GE. Birds rarely hybridize: A citizen science approach to estimating rates of hybridization in the wild*. Evolution 2020; 74:1216-1223. [DOI: 10.1111/evo.13943] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Revised: 01/24/2020] [Accepted: 02/04/2020] [Indexed: 01/09/2023]
Affiliation(s)
| | - Corey T. Callaghan
- Centre for Ecosystem Science, School of Biological, Earth and Environmental SciencesUNSW Sydney Sydney NSW 2052 Australia
| | - Geoffrey E. Hill
- Department of Biological SciencesAuburn University Auburn Alabama 36849
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45
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Barth JMI, Gubili C, Matschiner M, Tørresen OK, Watanabe S, Egger B, Han YS, Feunteun E, Sommaruga R, Jehle R, Schabetsberger R. Stable species boundaries despite ten million years of hybridization in tropical eels. Nat Commun 2020; 11:1433. [PMID: 32188850 PMCID: PMC7080837 DOI: 10.1038/s41467-020-15099-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 02/07/2020] [Indexed: 02/01/2023] Open
Abstract
Genomic evidence is increasingly underpinning that hybridization between taxa is commonplace, challenging our views on the mechanisms that maintain their boundaries. Here, we focus on seven catadromous eel species (genus Anguilla) and use genome-wide sequence data from more than 450 individuals sampled across the tropical Indo-Pacific, morphological information, and three newly assembled draft genomes to compare contemporary patterns of hybridization with signatures of past introgression across a time-calibrated phylogeny. We show that the seven species have remained distinct for up to 10 million years and find that the current frequencies of hybridization across species pairs contrast with genomic signatures of past introgression. Based on near-complete asymmetry in the directionality of hybridization and decreasing frequencies of later-generation hybrids, we suggest cytonuclear incompatibilities, hybrid breakdown, and purifying selection as mechanisms that can support species cohesion even when hybridization has been pervasive throughout the evolutionary history of clades.
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Affiliation(s)
- Julia M I Barth
- Department of Environmental Sciences, Zoological Institute, University of Basel, Vesalgasse 1, 4051, Basel, Switzerland
| | - Chrysoula Gubili
- Fisheries Research Institute, Hellenic Agricultural Organisation-DEMETER, Nea Peramos, 64 007, Kavala, Greece
| | - Michael Matschiner
- Department of Palaeontology and Museum, University of Zurich, Karl-Schmid-Strasse 4, 8006, Zurich, Switzerland.
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, 0316, Oslo, Norway.
| | - Ole K Tørresen
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, 0316, Oslo, Norway
| | - Shun Watanabe
- Faculty of Agriculture, Kindai University, 3327-204 Nakamachi, Nara, 631-8505, Japan
| | - Bernd Egger
- Department of Environmental Sciences, Zoological Institute, University of Basel, Vesalgasse 1, 4051, Basel, Switzerland
| | - Yu-San Han
- Institute of Fisheries Science, College of Life Science, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan
| | - Eric Feunteun
- Laboratoire Biologie des Organismes et Écosystèmes Aquatiques (BOREA), Muséum National d'Histoire Naturelle, CNRS, Sorbonne Université, Université de Caen Normandie, Université des Antilles, IRD, 61 Rue Buffon, CP 53, 75231, Paris Cedex 05, France
- MNHN-Station Marine de Dinard, Centre de Recherche et d'Enseignement Sur les Systèmes Côtiers (CRESCO), 38 Rue du Port Blanc, 35800, Dinard, France
| | - Ruben Sommaruga
- Department of Ecology, University of Innsbruck, Technikerstr. 25, 6020, Innsbruck, Austria
| | - Robert Jehle
- School of Science, Engineering and Environment, University of Salford, Salford Crescent, Salford, M5 4WT, UK.
| | - Robert Schabetsberger
- Department of Biosciences, University of Salzburg, Hellbrunnerstrasse 34, 5020, Salzburg, Austria.
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46
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Abstract
Interspecific hybridization is the process where closely related species mate and produce offspring with admixed genomes. The genomic revolution has shown that hybridization is common, and that it may represent an important source of novel variation. Although most interspecific hybrids are sterile or less fit than their parents, some may survive and reproduce, enabling the transfer of adaptive variants across the species boundary, and even result in the formation of novel evolutionary lineages. There are two main variants of hybrid species genomes: allopolyploid, which have one full chromosome set from each parent species, and homoploid, which are a mosaic of the parent species genomes with no increase in chromosome number. The establishment of hybrid species requires the development of reproductive isolation against parental species. Allopolyploid species often have strong intrinsic reproductive barriers due to differences in chromosome number, and homoploid hybrids can become reproductively isolated from the parent species through assortment of genetic incompatibilities. However, both types of hybrids can become further reproductively isolated, gaining extrinsic isolation barriers, by exploiting novel ecological niches, relative to their parents. Hybrids represent the merging of divergent genomes and thus face problems arising from incompatible combinations of genes. Thus hybrid genomes are highly dynamic and undergo rapid evolutionary change, including genome stabilization in which selection against incompatible combinations results in fixation of compatible ancestry block combinations within the hybrid species. The potential for rapid adaptation or speciation makes hybrid genomes a particularly exciting subject of in evolutionary biology. Here we summarize how introgressed alleles or hybrid species can establish and how the resulting hybrid genomes evolve.
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Affiliation(s)
- Anna Runemark
- Department of Biology, Lund University, Lund, Sweden
- * E-mail:
| | - Mario Vallejo-Marin
- Biological and Environmental Sciences, University of Stirling, Stirling, Scotland, United Kingdom
| | - Joana I. Meier
- St John's College, Cambridge, Cambridge, United Kingdom
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
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47
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Gainsford A, Jones GP, Gardner MG, van Herwerden L. Characterisation and cross-amplification of 42 microsatellite markers in two Amphiprion species (Pomacentridae) and a natural hybrid anemonefish to inform genetic structure within a hybrid zone. Mol Biol Rep 2019; 47:1521-1525. [PMID: 31749119 DOI: 10.1007/s11033-019-05190-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Accepted: 11/09/2019] [Indexed: 12/13/2022]
Abstract
The hybrid anemonefish, Amphiprion leucokranos, is known to be the product of ongoing, introgressive hybridization between parent taxa Amphiprion sandaracinos and Amphiprion chrysopterus. Hybridization is an important evolutionary phenomenon contributing to biodiversity within marine systems, where hybrid zones provide ideal systems in which to study hybridization events. Here, a suite of 42 Amphiprion microsatellite markers (including development of 8 novel markers) were cross-amplified in individuals from parent taxa and hybrid populations to facilitate investigation into the relatedness of hybridizing species across the A. leucokranos hybrid zone. Analysis revealed 15, 20 and 24 highly polymorphic loci (PIC > 0.5) in the two parent species and hybrid, respectively, for use in population genetic and parentage studies, with 305 unique alleles found overall (ranging from 1 to 13 alleles per locus) and 7 alleles per locus on average. Observed and expected heterozygosities ranged from 0.000 to 1.000 and 0.000 to 0.978, respectively. Significant deviations from Hardy-Weinberg equilibrium were found in eight loci, possibly due to relatedness among samples or the presence of null alleles. Use of the suite of markers tested here will provide valuable insights into the contemporary population structure and introgression among species and hybrids within the Amphiprion leucokranos hybrid zone, as well as inform future ecological and evolutionary studies of anemonefishes more broadly.
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Affiliation(s)
- A Gainsford
- College of Marine and Environmental Sciences, James Cook University, Townsville, QLD, 4811, Australia.
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia.
| | - G P Jones
- College of Marine and Environmental Sciences, James Cook University, Townsville, QLD, 4811, Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia
| | - M G Gardner
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia
- Australian Centre for Evolutionary Biology and Biodiversity, University of Adelaide, Adelaide, SA, 5005, Australia
- Evolutionary Biology Unit, South Australian Museum, North Terrace, Adelaide, SA, 5000, Australia
| | - L van Herwerden
- College of Marine and Environmental Sciences, James Cook University, Townsville, QLD, 4811, Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia
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48
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Demko AD, Sosa-López JR, Mennill DJ. Subspecies discrimination on the basis of acoustic signals: a playback experiment in a Neotropical songbird. Anim Behav 2019. [DOI: 10.1016/j.anbehav.2019.08.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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49
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Hybridization increases population variation during adaptive radiation. Proc Natl Acad Sci U S A 2019; 116:23216-23224. [PMID: 31659024 DOI: 10.1073/pnas.1913534116] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Adaptive radiations are prominent components of the world's biodiversity. They comprise many species derived from one or a small number of ancestral species in a geologically short time that have diversified into a variety of ecological niches. Several authors have proposed that introgressive hybridization has been important in the generation of new morphologies and even new species, but how that happens throughout evolutionary history is not known. Interspecific gene exchange is expected to have greatest impact on variation if it occurs after species have diverged genetically and phenotypically but before genetic incompatibilities arise. We use a dated phylogeny to infer that populations of Darwin's finches in the Galápagos became more variable in morphological traits through time, consistent with the hybridization hypothesis, and then declined in variation after reaching a peak. Some species vary substantially more than others. Phylogenetic inferences of hybridization are supported by field observations of contemporary hybridization. Morphological effects of hybridization have been investigated on the small island of Daphne Major by documenting changes in hybridizing populations of Geospiza fortis and Geospiza scandens over a 30-y period. G. scandens showed more evidence of admixture than G. fortis Beaks of G. scandens became progressively blunter, and while variation in length increased, variation in depth decreased. These changes imply independent effects of introgression on 2, genetically correlated, beak dimensions. Our study shows how introgressive hybridization can alter ecologically important traits, increase morphological variation as a radiation proceeds, and enhance the potential for future evolution in changing environments.
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50
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Weir JT, Price TD. Song playbacks demonstrate slower evolution of song discrimination in birds from Amazonia than from temperate North America. PLoS Biol 2019; 17:e3000478. [PMID: 31639139 PMCID: PMC6804960 DOI: 10.1371/journal.pbio.3000478] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 09/17/2019] [Indexed: 11/19/2022] Open
Abstract
Genetic data indicate differences in speciation rate across latitudes, but underlying causes have been difficult to assess because a critical phase of the speciation process is initiated in allopatry, in which, by definition, individuals from different taxa do not interact. We conducted song playback experiments between 109 related pairs of mostly allopatric bird species or subspecies in Amazonia and North America to compare the rate of evolution of male discrimination of songs. Relative to local controls, the number of flyovers and approach to the speaker were higher in Amazonia. We estimate that responses to songs of relatives are being lost about 6 times more slowly in Amazonia than in North America. The slow loss of response holds even after accounting for differences in song frequency and song length. Amazonian species with year-round territories are losing aggressive responses especially slowly. We suggest the presence of many species and extensive interspecific territoriality favors recognition of songs sung by sympatric heterospecifics, which results in a broader window of recognition and hence an ongoing response to novel similar songs. These aggressive responses should slow the establishment of sympatry between recently diverged forms. If male responses to novel allopatric taxa reflect female responses, then premating reproductive isolation is also evolving more slowly in Amazonia. The findings are consistent with previously demonstrated slower recent rates of expansion of sister taxa into sympatry, slower rates of evolution of traits important for premating isolation, and slower rates of speciation in general in Amazonia than in temperate North America.
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Affiliation(s)
- Jason T. Weir
- Department of Ecology and Evolution, University of Chicago, Chicago, Illinois, United States of America
- Department of Ecology and Evolutionary Biology and Department of Biological Sciences, University of Toronto, Toronto, Canada
- Department of Natural History, Royal Ontario Museum, Toronto, Canada
- * E-mail:
| | - Trevor D. Price
- Department of Ecology and Evolution, University of Chicago, Chicago, Illinois, United States of America
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