1
|
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.
Collapse
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
| |
Collapse
|
2
|
Moran BM, Payne CY, Powell DL, Iverson ENK, Donny AE, Banerjee SM, Langdon QK, Gunn TR, Rodriguez-Soto RA, Madero A, Baczenas JJ, Kleczko KM, Liu F, Matney R, Singhal K, Leib RD, Hernandez-Perez O, Corbett-Detig R, Frydman J, Gifford C, Schartl M, Havird JC, Schumer M. A lethal mitonuclear incompatibility in complex I of natural hybrids. Nature 2024; 626:119-127. [PMID: 38200310 PMCID: PMC10830419 DOI: 10.1038/s41586-023-06895-8] [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: 07/30/2021] [Accepted: 11/23/2023] [Indexed: 01/12/2024]
Abstract
The evolution of reproductive barriers is the first step in the formation of new species and can help us understand the diversification of life on Earth. These reproductive barriers often take the form of hybrid incompatibilities, in which alleles derived from two different species no longer interact properly in hybrids1-3. Theory predicts that hybrid incompatibilities may be more likely to arise at rapidly evolving genes4-6 and that incompatibilities involving multiple genes should be common7,8, but there has been sparse empirical data to evaluate these predictions. Here we describe a mitonuclear incompatibility involving three genes whose protein products are in physical contact within respiratory complex I of naturally hybridizing swordtail fish species. Individuals homozygous for mismatched protein combinations do not complete embryonic development or die as juveniles, whereas those heterozygous for the incompatibility have reduced complex I function and unbalanced representation of parental alleles in the mitochondrial proteome. We find that the effects of different genetic interactions on survival are non-additive, highlighting subtle complexity in the genetic architecture of hybrid incompatibilities. Finally, we document the evolutionary history of the genes involved, showing signals of accelerated evolution and evidence that an incompatibility has been transferred between species via hybridization.
Collapse
Affiliation(s)
- Benjamin M Moran
- Department of Biology, Stanford University, Stanford, CA, USA.
- Centro de Investigaciones Científicas de las Huastecas 'Aguazarca', A.C., Calnali, Hidalgo, Mexico.
| | - Cheyenne Y Payne
- Department of Biology, Stanford University, Stanford, CA, USA
- Centro de Investigaciones Científicas de las Huastecas 'Aguazarca', A.C., Calnali, Hidalgo, Mexico
| | - Daniel L Powell
- Department of Biology, Stanford University, Stanford, CA, USA
- Centro de Investigaciones Científicas de las Huastecas 'Aguazarca', A.C., Calnali, Hidalgo, Mexico
| | - Erik N K Iverson
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
| | | | | | - Quinn K Langdon
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Theresa R Gunn
- Department of Biology, Stanford University, Stanford, CA, USA
| | | | - Angel Madero
- Department of Biology, Stanford University, Stanford, CA, USA
| | - John J Baczenas
- Department of Biology, Stanford University, Stanford, CA, USA
| | | | - Fang Liu
- Stanford University Mass Spectrometry Core, Stanford University, Stanford, CA, USA
| | - Rowan Matney
- Stanford University Mass Spectrometry Core, Stanford University, Stanford, CA, USA
| | - Kratika Singhal
- Stanford University Mass Spectrometry Core, Stanford University, Stanford, CA, USA
| | - Ryan D Leib
- Stanford University Mass Spectrometry Core, Stanford University, Stanford, CA, USA
| | - Osvaldo Hernandez-Perez
- Centro de Investigaciones Científicas de las Huastecas 'Aguazarca', A.C., Calnali, Hidalgo, Mexico
| | - Russell Corbett-Detig
- Genomics Institute, University of California Santa Cruz, Santa Cruz, CA, USA
- Department of Biomolecular Engineering, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Judith Frydman
- Department of Biology, Stanford University, Stanford, CA, USA
- Department of Genetics, Stanford University, Stanford, CA, USA
| | - Casey Gifford
- Department of Genetics, Stanford University, Stanford, CA, USA
- Department of Pediatrics, Stanford University, Stanford, CA, USA
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, CA, USA
| | - Manfred Schartl
- The Xiphophorus Genetic Stock Center, Texas State University, San Marcos, TX, USA
- Developmental Biochemistry, Biozentrum, University of Würzburg, Würzburg, Germany
| | - Justin C Havird
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
| | - Molly Schumer
- Department of Biology, Stanford University, Stanford, CA, USA.
- Centro de Investigaciones Científicas de las Huastecas 'Aguazarca', A.C., Calnali, Hidalgo, Mexico.
- Howard Hughes Medical Institute, Stanford, CA, USA.
| |
Collapse
|
3
|
Langdon QK, Groh JS, Aguillon SM, Powell DL, Gunn T, Payne C, Baczenas JJ, Donny A, Dodge TO, Du K, Schartl M, Ríos-Cárdenas O, Gutierrez-Rodríguez C, Morris M, Schumer M. Genome evolution is surprisingly predictable after initial hybridization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.21.572897. [PMID: 38187753 PMCID: PMC10769416 DOI: 10.1101/2023.12.21.572897] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Over the past two decades, evolutionary biologists have come to appreciate that hybridization, or genetic exchange between distinct lineages, is remarkably common - not just in particular lineages but in taxonomic groups across the tree of life. As a result, the genomes of many modern species harbor regions inherited from related species. This observation has raised fundamental questions about the degree to which the genomic outcomes of hybridization are repeatable and the degree to which natural selection drives such repeatability. However, a lack of appropriate systems to answer these questions has limited empirical progress in this area. Here, we leverage independently formed hybrid populations between the swordtail fish Xiphophorus birchmanni and X. cortezi to address this fundamental question. We find that local ancestry in one hybrid population is remarkably predictive of local ancestry in another, demographically independent hybrid population. Applying newly developed methods, we can attribute much of this repeatability to strong selection in the earliest generations after initial hybridization. We complement these analyses with time-series data that demonstrates that ancestry at regions under selection has remained stable over the past ~40 generations of evolution. Finally, we compare our results to the well-studied X. birchmanni×X. malinche hybrid populations and conclude that deeper evolutionary divergence has resulted in stronger selection and higher repeatability in patterns of local ancestry in hybrids between X. birchmanni and X. cortezi.
Collapse
Affiliation(s)
- Quinn K. Langdon
- Department of Biology, Stanford University
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C
- Gladstone Institute of Virology, Gladstone Institutes, San Francisco, California
| | - Jeffrey S. Groh
- Center for Population Biology and Department of Evolution and Ecology, University of California, Davis
| | - Stepfanie M. Aguillon
- Department of Biology, Stanford University
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles
| | - Daniel L. Powell
- Department of Biology, Stanford University
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C
| | - Theresa Gunn
- Department of Biology, Stanford University
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C
| | - Cheyenne Payne
- Department of Biology, Stanford University
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C
| | | | - Alex Donny
- Department of Biology, Stanford University
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C
| | - Tristram O. Dodge
- Department of Biology, Stanford University
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C
| | - Kang Du
- Xiphophorus Genetic Stock Center, Texas State University San Marcos
| | - Manfred Schartl
- Xiphophorus Genetic Stock Center, Texas State University San Marcos
- Developmental Biochemistry, Biocenter, University of Würzburg
| | | | | | | | - Molly Schumer
- Department of Biology, Stanford University
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C
- Freeman Hrabowski Fellow, Howard Hughes Medical Institute
| |
Collapse
|
4
|
Nikolakis ZL, Schield DR, Westfall AK, Perry BW, Ivey KN, Orton RW, Hales NR, Adams RH, Meik JM, Parker JM, Smith CF, Gompert Z, Mackessy SP, Castoe TA. Evidence that genomic incompatibilities and other multilocus processes impact hybrid fitness in a rattlesnake hybrid zone. Evolution 2022; 76:2513-2530. [PMID: 36111705 DOI: 10.1111/evo.14612] [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: 09/04/2021] [Revised: 06/24/2022] [Accepted: 08/15/2022] [Indexed: 01/22/2023]
Abstract
Hybrid zones provide valuable opportunities to understand the genomic mechanisms that promote speciation by providing insight into factors involved in intermediate stages of speciation. Here, we investigate introgression in a hybrid zone between two rattlesnake species (Crotalus viridis and Crotalus oreganus concolor) that have undergone historical allopatric divergence and recent range expansion and secondary contact. We use Bayesian genomic cline models to characterize genomic patterns of introgression between these lineages and identify loci potentially subject to selection in hybrids. We find evidence for a large number of genomic regions with biased ancestry that deviate from the genomic background in hybrids (i.e., excess ancestry loci), which tend to be associated with genomic regions with higher recombination rates. We also identify suites of excess ancestry loci that show highly correlated allele frequencies (including conspecific and heterospecific combinations) across physically unlinked genomic regions in hybrids. Our findings provide evidence for multiple multilocus evolutionary processes impacting hybrid fitness in this system.
Collapse
Affiliation(s)
- Zachary L Nikolakis
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019
| | - Drew R Schield
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019.,Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, 80309
| | - Aundrea K Westfall
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019
| | - Kathleen N Ivey
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019
| | - Richard W Orton
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019
| | - Nicole R Hales
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019
| | - Richard H Adams
- Department of Biological and Environmental Sciences, Georgia College and State University, Milledgeville, Georgia, 31061
| | - Jesse M Meik
- Department of Biological Sciences, Tarleton State University, Stephenville, Texas, 76402
| | - Joshua M Parker
- Department of Life Sciences, Fresno City College, Fresno, California, 93741
| | - Cara F Smith
- School of Biological Sciences, University of Northern Colorado, Greeley, Colorado, 80639
| | | | - Stephen P Mackessy
- School of Biological Sciences, University of Northern Colorado, Greeley, Colorado, 80639
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019
| |
Collapse
|
5
|
Muralidhar P, Coop G, Veller C. Assortative mating enhances postzygotic barriers to gene flow via ancestry bundling. Proc Natl Acad Sci U S A 2022; 119:e2122179119. [PMID: 35858444 PMCID: PMC9335313 DOI: 10.1073/pnas.2122179119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 06/06/2022] [Indexed: 01/21/2023] Open
Abstract
Hybridization and subsequent genetic introgression are now known to be common features of the histories of many species, including our own. Following hybridization, selection often purges introgressed DNA genome-wide. While assortative mating can limit hybridization in the first place, it is also known to play an important role in postzygotic selection against hybrids and, thus, the purging of introgressed DNA. However, this role is usually thought of as a direct one: a tendency for mates to be conspecific reduces the sexual fitness of hybrids, reducing the transmission of introgressed ancestry. Here, we explore a second, indirect role of assortative mating as a postzygotic barrier to gene flow. Under assortative mating, parents covary in their ancestry, causing ancestry to be "bundled" in their offspring and later generations. This bundling effect increases ancestry variance in the population, enhancing the efficiency with which postzygotic selection purges introgressed DNA. Using whole-genome simulations, we show that the bundling effect can comprise a substantial portion of mate choice's overall effect as a postzygotic barrier to gene flow. We then derive a simple method for estimating the impact of the bundling effect from standard metrics of assortative mating. Applying this method to data from a diverse set of hybrid zones, we find that the bundling effect increases the purging of introgressed DNA by between 1.2-fold (in a baboon system with weak assortative mating) and 14-fold (in a swordtail system with strong assortative mating). Thus, assortative mating's bundling effect contributes substantially to the genetic isolation of species.
Collapse
Affiliation(s)
- Pavitra Muralidhar
- Department of Evolution and Ecology, University of California, 95616 Davis, CA
- Center for Population Biology, University of California, 95616 Davis, CA
| | - Graham Coop
- Department of Evolution and Ecology, University of California, 95616 Davis, CA
- Center for Population Biology, University of California, 95616 Davis, CA
| | - Carl Veller
- Department of Evolution and Ecology, University of California, 95616 Davis, CA
- Center for Population Biology, University of California, 95616 Davis, CA
| |
Collapse
|
6
|
Langdon QK, Powell DL, Kim B, Banerjee SM, Payne C, Dodge TO, Moran B, Fascinetto-Zago P, Schumer M. Predictability and parallelism in the contemporary evolution of hybrid genomes. PLoS Genet 2022; 18:e1009914. [PMID: 35085234 PMCID: PMC8794199 DOI: 10.1371/journal.pgen.1009914] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 10/28/2021] [Indexed: 12/28/2022] Open
Abstract
Hybridization between species is widespread across the tree of life. As a result, many species, including our own, harbor regions of their genome derived from hybridization. Despite the recognition that this process is widespread, we understand little about how the genome stabilizes following hybridization, and whether the mechanisms driving this stabilization tend to be shared across species. Here, we dissect the drivers of variation in local ancestry across the genome in replicated hybridization events between two species pairs of swordtail fish: Xiphophorus birchmanni × X. cortezi and X. birchmanni × X. malinche. We find unexpectedly high levels of repeatability in local ancestry across the two types of hybrid populations. This repeatability is attributable in part to the fact that the recombination landscape and locations of functionally important elements play a major role in driving variation in local ancestry in both types of hybrid populations. Beyond these broad scale patterns, we identify dozens of regions of the genome where minor parent ancestry is unusually low or high across species pairs. Analysis of these regions points to shared sites under selection across species pairs, and in some cases, shared mechanisms of selection. We show that one such region is a previously unknown hybrid incompatibility that is shared across X. birchmanni × X. cortezi and X. birchmanni × X. malinche hybrid populations.
Collapse
Affiliation(s)
- Quinn K. Langdon
- Department of Biology, Stanford University, Stanford, California, United States of America
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Mexico
| | - Daniel L. Powell
- Department of Biology, Stanford University, Stanford, California, United States of America
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Mexico
| | - Bernard Kim
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Shreya M. Banerjee
- Department of Biology, Stanford University, Stanford, California, United States of America
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Mexico
| | - Cheyenne Payne
- Department of Biology, Stanford University, Stanford, California, United States of America
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Mexico
| | - Tristram O. Dodge
- Department of Biology, Stanford University, Stanford, California, United States of America
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Mexico
| | - Ben Moran
- Department of Biology, Stanford University, Stanford, California, United States of America
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Mexico
| | - Paola Fascinetto-Zago
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Mexico
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
| | - Molly Schumer
- Department of Biology, Stanford University, Stanford, California, United States of America
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Mexico
- Hanna H. Gray Fellow, Howard Hughes Medical Institutes, Chevy Chase, Maryland, United States of America
| |
Collapse
|
7
|
Janzen T, Miró Pina V. Estimating the time since admixture from phased and unphased molecular data. Mol Ecol Resour 2021; 22:908-926. [PMID: 34599646 PMCID: PMC9291888 DOI: 10.1111/1755-0998.13519] [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: 09/29/2020] [Revised: 09/20/2021] [Accepted: 09/22/2021] [Indexed: 11/26/2022]
Abstract
After admixture, recombination breaks down genomic blocks of contiguous ancestry. The breakdown of these blocks forms a new “molecular clock” that ticks at a much faster rate than the mutation clock, enabling accurate dating of admixture events in the recent past. However, existing theory on the breakdown of these blocks, or the accumulation of delineations between blocks, so‐called “junctions”, has mostly been limited to using regularly spaced markers on phased data. Here, we present an extension to the theory of junctions using the ancestral recombination graph that describes the expected number of junctions for any distribution of markers along the genome. Furthermore, we provide a new framework to infer the time since admixture using unphased data. We demonstrate both the phased and unphased methods on simulated data and show that our new extensions have improved accuracy with respect to previous methods, especially for smaller population sizes and more ancient admixture times. Lastly, we demonstrate the applicability of our method on three empirical data sets, including labcrosses of yeast (Saccharomyces cerevisae) and two case studies of hybridization in swordtail fish and Populus trees.
Collapse
Affiliation(s)
- Thijs Janzen
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands.,Carl von Ossietzky University, Oldenburg, Germany
| | - Verónica Miró Pina
- Instituto de Investigaciones en Matemáticas Aplicadas y Sistemas (IIMAS), Universidad Nacional Autónoma de México (UNAM), México City, México.,Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra (UPF), Barcelona, Spain
| |
Collapse
|