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Aguillon SM, Haase Cox SK, Langdon QK, Gunn TR, Baczenas JJ, Banerjee SM, Donny AE, Moran BM, Gutiérrez-Rodríguez C, Ríos-Cárdenas O, Morris MR, Powell DL, Schumer M. Pervasive gene flow despite strong and varied reproductive barriers in swordtails. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.16.589374. [PMID: 38659793 PMCID: PMC11042374 DOI: 10.1101/2024.04.16.589374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
One of the mechanisms that can lead to the formation of new species occurs through the evolution of reproductive barriers. However, recent research has demonstrated that hybridization has been pervasive across the tree of life even in the presence of strong barriers. Swordtail fishes (genus Xiphophorus) are an emerging model system for studying the interface between these barriers and hybridization. We document overlapping mechanisms that act as barriers between closely related species, X. birchmanni and X. cortezi, by combining genomic sequencing from natural hybrid populations, artificial crosses, behavioral assays, sperm performance, and developmental studies. We show that strong assortative mating plays a key role in maintaining subpopulations with distinct ancestry in natural hybrid populations. Lab experiments demonstrate that artificial F1 crosses experience dysfunction: crosses with X. birchmanni females were largely inviable and crosses with X. cortezi females had a heavily skewed sex ratio. Using F2 hybrids we identify several genomic regions that strongly impact hybrid viability. Strikingly, two of these regions underlie genetic incompatibilities in hybrids between X. birchmanni and its sister species X. malinche. Our results demonstrate that ancient hybridization has played a role in the origin of this shared genetic incompatibility. Moreover, ancestry mismatch at these incompatible regions has remarkably similar consequences for phenotypes and hybrid survival in X. cortezi × X. birchmanni hybrids as in X. malinche × X. birchmanni hybrids. Our findings identify varied reproductive barriers that shape genetic exchange between naturally hybridizing species and highlight the complex evolutionary outcomes of hybridization.
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Affiliation(s)
- Stepfanie M. Aguillon
- Department of Biology, Stanford University, Stanford, CA, USA
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Hidalgo, México
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA, USA
| | | | - Quinn K. Langdon
- Department of Biology, Stanford University, Stanford, CA, USA
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Hidalgo, México
- Gladstone Institute of Virology, Gladstone Institutes, San Francisco, CA, USA
| | - Theresa R. Gunn
- Department of Biology, Stanford University, Stanford, CA, USA
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Hidalgo, México
| | | | - Shreya M. Banerjee
- Department of Biology, Stanford University, Stanford, CA, USA
- Center for Population Biology, University of California, Davis, Davis, CA, USA
| | | | - Benjamin M. Moran
- Department of Biology, Stanford University, Stanford, CA, USA
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Hidalgo, México
| | | | - Oscar Ríos-Cárdenas
- Red de Biología Evolutiva, Instituto de Ecología A.C., Xalapa, Veracruz, México
| | - Molly R. Morris
- Department of Biological Sciences, Ohio University, Athens, Ohio, USA
| | - Daniel L. Powell
- Department of Biology, Stanford University, Stanford, CA, USA
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Hidalgo, México
| | - Molly Schumer
- Department of Biology, Stanford University, Stanford, CA, USA
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Hidalgo, México
- Freeman Hrabowski Fellow, Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
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Sasínková M, Balvín O, Vandrovcová J, Massino C, Weig AR, Reinhardt K, Otti O, Bartonička T. Despite genetic isolation in sympatry, post-copulatory reproductive barriers have not evolved between bat- and human-associated common bedbugs (Cimex lectularius L.). Front Zool 2023; 20:36. [PMID: 37950221 PMCID: PMC10636883 DOI: 10.1186/s12983-023-00514-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 10/29/2023] [Indexed: 11/12/2023] Open
Abstract
BACKGROUND The common bedbug Cimex lectularius is a widespread ectoparasite on humans and bats. Two genetically isolated lineages, parasitizing either human (HL) or bat (BL) hosts, have been suggested to differentiate because of their distinct ecology. The distribution range of BL is within that of HL and bedbugs live mostly on synanthropic bat hosts. This sympatric co-occurrence predicts strong reproductive isolation at the post-copulatory level. RESULTS We tested the post-copulatory barrier in three BL and three HL populations in reciprocal crosses, using a common-garden blood diet that was novel to both lineages. We excluded pre-copulation isolation mechanisms and studied egg-laying rates after a single mating until the depletion of sperm, and the fitness of the resulting offspring. We found a higher sperm storage capability in BL, likely reflecting the different seasonal availability of HL and BL hosts. We also observed a notable variation in sperm function at the population level within lineages and significant differences in fecundity and offspring fitness between lineages. However, no difference in egg numbers or offspring fitness was observed between within- and between-lineage crosses. CONCLUSIONS Differences in sperm storage or egg-laying rates between HL and BL that we found did not affect reproductive isolation. Neither did the population-specific variation in sperm function. Overall, our results show no post-copulatory reproductive isolation between the lineages. How genetic differentiation in sympatry is maintained in the absence of a post-copulatory barrier between BL and HL remains to be investigated.
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Affiliation(s)
- Markéta Sasínková
- Department of Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, 165 21, Prague 6, Czech Republic
| | - Ondřej Balvín
- Department of Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, 165 21, Prague 6, Czech Republic
| | - Jana Vandrovcová
- Department of Botany and Zoology, Faculty of Science, Masaryk University , Kotlářská 2, 611 37, Brno, Czech Republic
| | - Christian Massino
- Applied Zoology, Department of Biology, Technische Universität Dresden, 01062, Dresden, Germany
| | - Alfons R Weig
- Genomics and Bioinformatics, University of Bayreuth, Universitätsstrasse 30, 95440, Bayreuth, Germany
| | - Klaus Reinhardt
- Applied Zoology, Department of Biology, Technische Universität Dresden, 01062, Dresden, Germany
| | - Oliver Otti
- Applied Zoology, Department of Biology, Technische Universität Dresden, 01062, Dresden, Germany
- Animal Population Ecology, Animal Ecology I, University of Bayreuth, Universitätsstrasse 30, 95440, Bayreuth, Germany
| | - Tomáš Bartonička
- Department of Botany and Zoology, Faculty of Science, Masaryk University , Kotlářská 2, 611 37, Brno, Czech Republic.
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Devigili A, Fitzpatrick JL, Gasparini C, Ramnarine IW, Pilastro A, Evans JP. Possible glimpses into early speciation: the effect of ovarian fluid on sperm velocity accords with post-copulatory isolation between two guppy populations. J Evol Biol 2017; 31:66-74. [PMID: 29044818 DOI: 10.1111/jeb.13194] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 08/12/2017] [Accepted: 10/12/2017] [Indexed: 12/28/2022]
Abstract
Identifying mechanisms of reproductive isolation is key to understanding speciation. Among the putative mechanisms underlying reproductive isolation, sperm-female interactions (post-mating-prezygotic barriers) are arguably the hardest to identify, not least because these are likely to operate at the cellular or molecular level. Yet sperm-female interactions offer great potential to prevent the transfer of genetic information between different populations at the initial stages of speciation. Here, we provide a preliminary test for the presence of a putative post-mating-prezygotic barrier operating between three populations of Trinidadian guppies (Poecilia reticulata), an internally fertilizing fish that inhabits streams with different levels of connectivity across Trinidad. We experimentally evaluate the effect of female ovarian fluid on sperm velocity (a predictor of competitive fertilization success) according to whether males and females were from the same (native) or different (foreign) populations. Our results reveal the potential for ovarian fluid to act as a post-mating-prezygotic barrier between two populations from different drainages, but also that the strength of this barrier is different among populations. This result may explain the previous finding that, in some populations, sperm from native males have precedence over foreign sperm, which could eventually lead to reproductive isolation between these populations.
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Affiliation(s)
- A Devigili
- Department of Zoology, Stockholm University, Stockholm, Sweden.,Department of Biology, University of Padova, Padua, Italy
| | - J L Fitzpatrick
- Department of Zoology, Stockholm University, Stockholm, Sweden.,Centre for Evolutionary Biology, School of Biological Sciences (M092), University of Western Australia, Crawley, WA, Australia
| | - C Gasparini
- Department of Biology, University of Padova, Padua, Italy.,Centre for Evolutionary Biology, School of Biological Sciences (M092), University of Western Australia, Crawley, WA, Australia
| | - I W Ramnarine
- Department of Life Sciences, University of the West Indies, St Augustine, Trinidad and Tobago
| | - A Pilastro
- Department of Biology, University of Padova, Padua, Italy
| | - J P Evans
- Centre for Evolutionary Biology, School of Biological Sciences (M092), University of Western Australia, Crawley, WA, Australia
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