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Hurtado-Gómez JP, Vargas-Ramírez M, Iverson JB, Joyce WG, McCranie JR, Paetzold C, Fritz U. Diversity and biogeography of South American mud turtles elucidated by multilocus DNA sequencing (Testudines: Kinosternidae). Mol Phylogenet Evol 2024; 197:108083. [PMID: 38679303 DOI: 10.1016/j.ympev.2024.108083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 04/02/2024] [Accepted: 04/24/2024] [Indexed: 05/01/2024]
Abstract
Kinosternon is the most speciose genus of extant turtles, with 22 currently recognized species, distributed across large parts of the Americas. Most species have small distributions, but K. leucostomum and K. scorpioides range from Mexico to South America. Previous studies have found discordance between mitochondrial and nuclear phylogenies in some kinosternid groups, with the current taxonomy following the nuclear-based results. Herein, based on extended molecular, geographic, and taxonomic sampling, we explore the phylogeographic structure and taxonomic limits for K. leucostomum and the K. scorpioides group and present a fossil-calibrated nuclear time tree for Kinosternon. Our results reveal contrasting differentiation patterns for the K. scorpioides group and K. leucostomum, despite overlapping distributions. Kinosternon leucostomum shows only shallow geographic divergence, whereas the K. scorpioides group is polyphyletic with up to 10 distinct taxa, some of them undescribed. We support the elevation of K. s. albogulare and K. s. cruentatum to species level. Given the deep divergence within the genus Kinosternon, we propose the recognition of three subgenera, Kinosternon, Cryptochelys and Thyrosternum, and the abandonment of the group-based classification, at least for the K. leucostomum and K. scorpioides groups. Our results show an initial split in Kinosternon that gave rise to two main radiations, one Nearctic and one mainly Neotropical. Most speciation events in Kinosternon occurred during the Quaternary and we hypothesize that they were mediated by both climatic and geological events. Additionally, our data imply that at least three South American colonizations occurred, two in the K. leucostomum group, and one in the K. scorpioides group. Additionally, we hypothesize that discordance between mitochondrial and nuclear phylogenetic signal is due to mitochondrial capture from an extinct kinosternine lineage.
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Affiliation(s)
| | - Mario Vargas-Ramírez
- Grupo Biodiversidad y Conservación Genética, Instituto de Genética, Universidad Nacional de Colombia, Bogotá, Colombia; Estación de Biología Tropical Roberto Franco (EBTRF), Universidad Nacional de Colombia, Villavicencio, Colombia
| | - John B Iverson
- Department of Biology, Earlham College, Richmond, IN 47374, USA
| | - Walter G Joyce
- Department of Geosciences, University of Fribourg, 1700 Fribourg, Switzerland
| | - James R McCranie
- Smithsonian Research Associate, 10770 SW 164th Street, Miami, FL 33157, USA
| | - Claudia Paetzold
- Museum of Zoology, Senckenberg Natural History Collections Dresden, 01109 Dresden, Germany
| | - Uwe Fritz
- Museum of Zoology, Senckenberg Natural History Collections Dresden, 01109 Dresden, Germany.
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2
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Horníková M, Lanier HC, Marková S, Escalante MA, Searle JB, Kotlík P. Genetic admixture drives climate adaptation in the bank vole. Commun Biol 2024; 7:863. [PMID: 39009753 PMCID: PMC11251159 DOI: 10.1038/s42003-024-06549-z] [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: 07/20/2023] [Accepted: 07/03/2024] [Indexed: 07/17/2024] Open
Abstract
Genetic admixture introduces new variants at relatively high frequencies, potentially aiding rapid responses to environmental changes. Here, we evaluate its role in adaptive variation related to climatic conditions in bank voles (Clethrionomys glareolus) in Britain, using whole-genome data. Our results reveal loci showing excess ancestry from one of the two postglacial colonist populations inconsistent with overall admixture patterns. Notably, loci associated with climate adaptation exhibit disproportionate amounts of excess ancestry, highlighting the impact of admixture between colonist populations on local adaptation. The results suggest strong and localized selection on climate-adaptive loci, as indicated by steep clines and/or shifted cline centres, during population replacement. A subset, including a haemoglobin gene, is associated with oxidative stress responses, underscoring a role of oxidative stress in local adaptation. Our study highlights the important contribution of admixture during secondary contact between populations from distinct climatic refugia enriching adaptive diversity. Understanding these dynamics is crucial for predicting future adaptive capacity to anthropogenic climate change.
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Affiliation(s)
- Michaela Horníková
- Laboratory of Molecular Ecology, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Liběchov, Czech Republic
| | - Hayley C Lanier
- Department of Biology, Program in Ecology & Evolutionary Biology, University of Oklahoma, Norman, OK, USA
- Sam Noble Museum, University of Oklahoma, Norman, OK, USA
| | - Silvia Marková
- Laboratory of Molecular Ecology, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Liběchov, Czech Republic
| | - Marco A Escalante
- Laboratory of Molecular Ecology, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Liběchov, Czech Republic
| | - Jeremy B Searle
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
| | - Petr Kotlík
- Laboratory of Molecular Ecology, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Liběchov, Czech Republic.
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3
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Farleigh K, Ascanio A, Farleigh ME, Schield DR, Card DC, Leal M, Castoe TA, Jezkova T, Rodríguez-Robles JA. Signals of differential introgression in the genome of natural hybrids of Caribbean anoles. Mol Ecol 2023; 32:6000-6017. [PMID: 37861454 DOI: 10.1111/mec.17170] [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: 12/28/2021] [Revised: 08/30/2023] [Accepted: 10/03/2023] [Indexed: 10/21/2023]
Abstract
Hybridization facilitates recombination between divergent genetic lineages and can be shaped by both neutral and selective processes. Upon hybridization, loci with no net fitness effects introgress randomly from parental species into the genomes of hybrid individuals. Conversely, alleles from one parental species at some loci may provide a selective advantage to hybrids, resulting in patterns of introgression that do not conform to random expectations. We investigated genomic patterns of differential introgression in natural hybrids of two species of Caribbean anoles, Anolis pulchellus and A. krugi in Puerto Rico. Hybrids exhibit A. pulchellus phenotypes but possess A. krugi mitochondrial DNA, originated from multiple, independent hybridization events, and appear to have replaced pure A. pulchellus across a large area in western Puerto Rico. Combining genome-wide SNP datasets with bioinformatic methods to identify signals of differential introgression in hybrids, we demonstrate that the genomes of hybrids are dominated by pulchellus-derived alleles and show only 10%-20% A. krugi ancestry. The majority of A. krugi loci in hybrids exhibit a signal of non-random differential introgression and include loci linked to genes involved in development and immune function. Three of these genes (delta like canonical notch ligand 1, jagged1 and notch receptor 1) affect cell differentiation and growth and interact with mitochondrial function. Our results suggest that differential non-random introgression for a subset of loci may be driven by selection favouring the inheritance of compatible mitochondrial and nuclear-encoded genes in hybrids.
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Affiliation(s)
- Keaka Farleigh
- Department of Biology, Miami University, Oxford, Ohio, USA
| | | | | | - Drew R Schield
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, USA
| | - Daren C Card
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
- Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, USA
| | - Manuel Leal
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, USA
| | - Todd A Castoe
- Department of Biology, University of Texas, Arlington, Arlington, Texas, USA
| | - Tereza Jezkova
- Department of Biology, Miami University, Oxford, Ohio, USA
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4
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Wang C, Yap ZY, Wan P, Chen K, Folk RA, Damrel DZ, Barger W, Diamond A, Horn C, Landry GP, Samarakoon T, Harvey S, Morgan DR, Qiu Y, Li P. Molecular phylogeography and historical demography of a widespread herbaceous species from eastern North America, Podophyllum peltatum. AMERICAN JOURNAL OF BOTANY 2023; 110:e16254. [PMID: 37938809 DOI: 10.1002/ajb2.16254] [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: 02/10/2023] [Revised: 09/22/2023] [Accepted: 09/25/2023] [Indexed: 11/10/2023]
Abstract
PREMISE Glacial/interglacial cycles and topographic complexity are both considered to have shaped today's diverse phylogeographic patterns of taxa from unglaciated eastern North America (ENA). However, few studies have focused on the phylogeography and population dynamics of wide-ranging ENA herbaceous species occurring in forest understory habitat. We examined the phylogeographic pattern and evolutionary history of Podophyllum peltatum L., a widely distributed herb inhabiting deciduous forests of ENA. METHODS Using chloroplast DNA (cpDNA) sequences and nuclear microsatellite loci, we investigated the population structure and genetic diversity of the species. Molecular dating, demographic history analyses, and ecological niche modeling were also performed to illustrate the phylogeographic patterns. RESULTS Our cpDNA results identified three main groups that are largely congruent with boundaries along the Appalachian Mountains and the Mississippi River, two major geographic barriers in ENA. Populations located to the east of the Appalachians and along the central Appalachians exhibited relatively higher levels of genetic diversity. Extant lineages may have diverged during the late Miocene, and range expansions of different groups may have happened during the Pleistocene glacial/interglacial cycles. CONCLUSIONS Our findings indicate that geographic barriers may have started to facilitate the population divergence in P. peltatum before the Pleistocene. Persistence in multiple refugia, including areas around the central Appalachians during the Quaternary glacial period, and subsequent expansions under hospitable climatic condition, especially westward expansion, are likely responsible for the species' contemporary genetic structure and phylogeographic pattern.
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Affiliation(s)
- Chenxi Wang
- Systematic & Evolutionary Botany and Biodiversity group, MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Zhao-Yan Yap
- Systematic & Evolutionary Botany and Biodiversity group, MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Penglei Wan
- Systematic & Evolutionary Botany and Biodiversity group, MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Kuangqi Chen
- Systematic & Evolutionary Botany and Biodiversity group, MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Ryan A Folk
- Department of Biological Sciences, Mississippi State University, Starkville, Mississippi, 39762, USA
| | - Dixie Z Damrel
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, 29634-0314, USA
| | - Wayne Barger
- Department of Conservation and Natural Resources, State Lands Division, Natural Heritage Section, Montgomery, Alabama, 36130, USA
| | - Alvin Diamond
- Department of Biological and Environmental Sciences, Troy University, Troy, Alabama, 36082, USA
| | - Charles Horn
- Department of Sciences and Mathematics, Newberry College, Newberry, South Carolina, 29108, USA
| | | | | | - Stephanie Harvey
- Department of Biology, Georgia Southwestern State University, Americus, Georgia, 31709-4376, USA
| | - David R Morgan
- Department of Natural Sciences, University of West Georgia, Carrollton, Georgia, 30118-2220, USA
| | - Yingxiong Qiu
- Systematic & Evolutionary Botany and Biodiversity group, MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
- Plant Biodiversity Research Centre, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, Hubei, 430074, China
| | - Pan Li
- Systematic & Evolutionary Botany and Biodiversity group, MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
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5
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Regmi B, Douglas MR, Wangchuk K, Zbinden ZD, Edds DR, Tshering S, Douglas ME. The Himalayan uplift and evolution of aquatic biodiversity across Asia: Snowtrout (Cyprininae: Schizothorax) as a test case. PLoS One 2023; 18:e0289736. [PMID: 37874844 PMCID: PMC10597529 DOI: 10.1371/journal.pone.0289736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 07/26/2023] [Indexed: 10/26/2023] Open
Abstract
Global biodiversity hotspots are often remote, tectonically active areas undergoing climatic fluctuations, such as the Himalaya Mountains and neighboring Qinghai-Tibetan Plateau (QTP). They provide biogeographic templates upon which endemic biodiversity can be mapped to infer diversification scenarios. Yet, this process can be somewhat opaque for the Himalaya, given substantial data gaps separating eastern and western regions. To help clarify, we evaluated phylogeographic and phylogenetic hypotheses for a widespread fish (Snowtrout: Cyprininae; Schizothorax) by sequencing 1,140 base pair of mtDNA cytochrome-b (cytb) from Central Himalaya samples (Nepal: N = 53; Bhutan: N = 19), augmented with 68 GenBank sequences (N = 60 Schizothorax/N = 8 outgroups). Genealogical relationships (N = 132) were analyzed via maximum likelihood (ML), Bayesian (BA), and haplotype network clustering, with clade divergence estimated via TimeTree. Snowtrout seemingly originated in Central Asia, dispersed across the QTP, then into Bhutan via southward-flowing tributaries of the east-flowing Yarlung-Tsangpo River (YLTR). Headwaters of five large Asian rivers provided dispersal corridors from Central into eastern/southeastern Asia. South of the Himalaya, the YLTR transitions into the Brahmaputra River, facilitating successive westward colonization of Himalayan drainages first in Bhutan, then Nepal, followed by far-western drainages subsequently captured by the (now) westward-flowing Indus River. Two distinct Bhutanese phylogenetic groups were recovered: Bhutan-1 (with three subclades) seemingly represents southward dispersal from the QTP; Bhutan-2 apparently illustrates northward colonization from the Lower Brahmaputra. The close phylogenetic/phylogeographic relationships between the Indus River (Pakistan) and western tributaries of the Upper Ganges (India/Nepal) potentially implicate an historic, now disjunct connection. Greater species-divergences occurred across rather than within-basins, suggesting vicariance as a driver. The Himalaya is a component of the Earth's largest glacial reservoir (i.e., the "third-pole") separate from the Arctic/Antarctic. Its unique aquatic biodiversity must be defined and conserved through broad, trans-national collaborations. Our study provides an initial baseline for this process.
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Affiliation(s)
- Binod Regmi
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, United States of America
| | - Marlis R. Douglas
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, United States of America
| | - Karma Wangchuk
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, United States of America
- National Research & Development Centre for Riverine and Lake Fisheries, Ministry of Agriculture & Forests, Royal Government of Bhutan, Thimphu, Bhutan
| | - Zachery D. Zbinden
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, United States of America
| | - David R. Edds
- Department of Biological Sciences, Emporia State University, Emporia, Kansas, United States of America
| | - Singye Tshering
- National Research & Development Centre for Riverine and Lake Fisheries, Ministry of Agriculture & Forests, Royal Government of Bhutan, Thimphu, Bhutan
| | - Michael E. Douglas
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, United States of America
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6
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Non-parallel morphological divergence following colonization of a new host plant. Evol Ecol 2022. [DOI: 10.1007/s10682-022-10189-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractAdaptation to new ecological niches is known to spur population diversification and may lead to speciation if gene flow is ceased. While adaptation to the same ecological niche is expected to be parallel, it is more difficult to predict whether selection against maladaptive hybridization in secondary sympatry results in parallel divergence also in traits that are not directly related to the ecological niches. Such parallelisms in response to selection for reproductive isolation can be identified through estimating parallelism in reproductive character displacement across different zones of secondary contact. Here, we use a host shift in the phytophagous peacock fly Tephritis conura, with both host races represented in two geographically separate areas East and West of the Baltic Sea to investigate convergence in morphological adaptations. We asked (i) if there are consistent morphological adaptations to a host plant shift and (ii) if the response to secondary sympatry with the alternate host race is parallel across contact zones. We found surprisingly low and variable, albeit significant, divergence between host races. Only one trait, the length of the female ovipositor, which serves an important function in the interaction with the hosts, was consistently different between host races. Instead, co-existence with the other host race significantly affected the degree of morphological divergence, but the divergence was largely driven by different traits in different contact zones. Thus, local stochastic fixation or reinforcement could generate trait divergence, and additional evidence is needed to conclude whether divergence is locally adaptive.
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7
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Payne C, Bovio R, Powell DL, Gunn TR, Banerjee SM, Grant V, Rosenthal GG, Schumer M. Genomic insights into variation in thermotolerance between hybridizing swordtail fishes. Mol Ecol 2022. [PMID: 35510780 DOI: 10.1111/mec.16489] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 02/22/2022] [Accepted: 04/19/2022] [Indexed: 11/30/2022]
Abstract
Understanding how organisms adapt to changing environments is a core focus of research in evolutionary biology. One common mechanism is adaptive introgression, which has received increasing attention as a potential route to rapid adaptation in populations struggling in the face of ecological change, particularly global climate change. However, hybridization can also result in deleterious genetic interactions that may limit the benefits of adaptive introgression. Here, we used a combination of genome-wide quantitative trait locus mapping and differential gene expression analyses between the swordtail fish species Xiphophorus malinche and X. birchmanni to study the consequences of hybridization on thermotolerance. While these two species are adapted to different thermal environments, we document a complicated architecture of thermotolerance in hybrids. We identify a region of the genome that contributes to reduced thermotolerance in individuals heterozygous for X. malinche and X. birchmanni ancestry, as well as widespread misexpression in hybrids of genes that respond to thermal stress in the parental species, particularly in the circadian clock pathway. We also show that a previously mapped hybrid incompatibility between X. malinche and X. birchmanni contributes to reduced thermotolerance in hybrids. Together, our results highlight the challenges of understanding the impact of hybridization on complex ecological traits and its potential impact on adaptive introgression.
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Affiliation(s)
- Cheyenne Payne
- Department of Biology, Stanford University, Stanford, California, USA
- Centro de Investigaciones Científicas de las Huastecas "Aguazarca", A.C., Calnali, Hidalgo, México
| | - Richard Bovio
- Centro de Investigaciones Científicas de las Huastecas "Aguazarca", A.C., Calnali, Hidalgo, México
- Department of Biology, Texas A&M University, College Station, Texas, USA
| | - Daniel L Powell
- Department of Biology, Stanford University, Stanford, California, USA
- Centro de Investigaciones Científicas de las Huastecas "Aguazarca", A.C., Calnali, Hidalgo, México
| | - Theresa R Gunn
- Department of Biology, Stanford University, Stanford, California, USA
- Centro de Investigaciones Científicas de las Huastecas "Aguazarca", A.C., Calnali, Hidalgo, México
| | - Shreya M Banerjee
- Department of Biology, Stanford University, Stanford, California, USA
- Centro de Investigaciones Científicas de las Huastecas "Aguazarca", A.C., Calnali, Hidalgo, México
| | - Victoria Grant
- Department of Biology, Stanford University, Stanford, California, USA
- Centro de Investigaciones Científicas de las Huastecas "Aguazarca", A.C., Calnali, Hidalgo, México
| | - Gil G Rosenthal
- Centro de Investigaciones Científicas de las Huastecas "Aguazarca", A.C., Calnali, Hidalgo, México
- Department of Biology, Texas A&M University, College Station, Texas, USA
- Department of Biology, University of Padua, Italy
| | - Molly Schumer
- Department of Biology, Stanford University, Stanford, California, USA
- Centro de Investigaciones Científicas de las Huastecas "Aguazarca", A.C., Calnali, Hidalgo, México
- Department of Biology, University of Padua, Italy
- Hanna H. Gray Fellow, Howard Hughes Medical Institute, Stanford, California, USA
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8
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Burbrink FT, Bernstein JM, Kuhn A, Gehara M, Ruane S. Ecological Divergence and the History of Gene Flow in the Nearctic Milksnakes (Lampropeltis triangulum Complex). Syst Biol 2021; 71:839-858. [PMID: 35043210 DOI: 10.1093/sysbio/syab093] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 11/11/2021] [Accepted: 11/15/2021] [Indexed: 11/13/2022] Open
Abstract
Many phylogeographic studies on species with large ranges have found genetic-geographic structure associated with changes in habitat and physical barriers preventing or reducing gene flow. These interactions with geographic space, contemporary and historical climate, and biogeographic barriers have complex effects on contemporary population genetic structure and processes of speciation. While allopatric speciation at biogeographic barriers is considered the primary mechanism for generating species, more recently it has been shown that parapatric modes of divergence may be equally or even more common. With genomic data and better modeling capabilities, we can more clearly define causes of speciation in relation to biogeography and migration between lineages, the location of hybrid zones with respect to the ecology of parental lineages, and differential introgression of genes between taxa. Here, we examine the origins of three Nearctic milksnakes (Lampropeltis elapsoides, Lampropeltis triangulum and Lampropeltis gentilis) using genome-scale data to better understand species diversification. Results from artificial neural networks show that a mix of a strong biogeographic barrier, environmental changes, and physical space has affected genetic structure in these taxa. These results underscore conspicuous environmental changes that occur as the sister taxa L. triangulum and L. gentilis diverged near the Great Plains into the forested regions of the Eastern Nearctic. This area has been recognized as a region for turnover for many vertebrate species, but as we show here the contemporary boundary does not isolate these sister species. These two species likely formed in the mid-Pleistocene and have remained partially reproductively isolated over much of this time, showing differential introgression of loci. We also demonstrate that when L. triangulum and L. gentilis are each in contact with the much older L. elapsoides, some limited gene flow has occurred. Given the strong agreement between nuclear and mtDNA genomes, along with estimates of ecological niche, we suggest that all three lineages should continue to be recognized as unique species. Furthermore, this work emphasizes the importance of considering complex modes of divergence and differential allelic introgression over a complex landscape when testing mechanisms of speciation. [Cline; delimitation; Eastern Nearctic; Great Plains; hybrids; introgression; speciation.].
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Affiliation(s)
- Frank T Burbrink
- Department of Herpetology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA
| | - Justin M Bernstein
- Department of Biological Sciences, Rutgers University Newark, 195 University Ave, Newark, NJ 07102, USA
| | - Arianna Kuhn
- Department of Herpetology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA
| | - Marcelo Gehara
- Department of Earth and Environmental Sciences, Rutgers University Newark, 195 University Ave, Newark, NJ 07102, USA
| | - Sara Ruane
- Department of Earth and Environmental Sciences, Rutgers University Newark, 195 University Ave, Newark, NJ 07102, USA.,Amphibian and Reptile Collection, Negaunee Integrative Research Center, Field Museum of Natural History, 1400 S Lake Shore Dr, Chicago, IL 60605, USA
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9
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Martin BT, Chafin TK, Douglas MR, Douglas ME. ClineHelpR: an R package for genomic cline outlier detection and visualization. BMC Bioinformatics 2021; 22:501. [PMID: 34656096 PMCID: PMC8520269 DOI: 10.1186/s12859-021-04423-x] [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: 07/27/2021] [Accepted: 10/04/2021] [Indexed: 11/30/2022] Open
Abstract
Background Patterns of multi-locus differentiation (i.e., genomic clines) often extend broadly across hybrid zones and their quantification can help diagnose how species boundaries are shaped by adaptive processes, both intrinsic and extrinsic. In this sense, the transitioning of loci across admixed individuals can be contrasted as a function of the genome-wide trend, in turn allowing an expansion of clinal theory across a much wider array of biodiversity. However, computational tools that serve to interpret and consequently visualize ‘genomic clines’ are limited, and users must often write custom, relatively complex code to do so. Results Here, we introduce the ClineHelpR R-package for visualizing genomic clines and detecting outlier loci using output generated by two popular software packages, bgc and Introgress. ClineHelpR bundles both input generation (i.e., filtering datasets and creating specialized file formats) and output processing (e.g., MCMC thinning and burn-in) with functions that directly facilitate interpretation and hypothesis testing. Tools are also provided for post-hoc analyses that interface with external packages such as ENMeval and RIdeogram. Conclusions Our package increases the reproducibility and accessibility of genomic cline methods, thus allowing an expanded user base and promoting these methods as mechanisms to address diverse evolutionary questions in both model and non-model organisms. Furthermore, the ClineHelpR extended functionality can evaluate genomic clines in the context of spatial and environmental features, allowing users to explore underlying processes potentially contributing to the observed patterns and helping facilitate effective conservation management strategies.
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Affiliation(s)
- Bradley T Martin
- Arkansas Conservation and Molecular Ecology Laboratory, Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA. .,University of Arkansas Global Campus, Fayetteville, AR, 72701, USA.
| | - Tyler K Chafin
- Arkansas Conservation and Molecular Ecology Laboratory, Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA.,Ecology and Evolutionary Biology Department, University of Colorado, Boulder, CO, USA
| | - Marlis R Douglas
- Arkansas Conservation and Molecular Ecology Laboratory, Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA
| | - Michael E Douglas
- Arkansas Conservation and Molecular Ecology Laboratory, Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA
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10
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Gallego-García N, Caballero S, Shaffer HB. Are genomic updates of well-studied species worth the investment for conservation? A case study of the Critically Endangered Magdalena River turtle. J Hered 2021; 112:575-589. [PMID: 34628509 DOI: 10.1093/jhered/esab063] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 10/08/2021] [Indexed: 11/13/2022] Open
Abstract
As genomic-scale data sets become economically feasible for most organisms, a key question for conservation biology is whether the increased resolution offered by new genomic approaches justifies repeating earlier studies based on traditional markers, rather than investing those same time and monetary resources in less-known species. Genomic studies offer clear advantages when the objective is to identify adaptive loci that may be critical to conservation policy-makers. However, the answer is far less certain for the population and landscape studies based on neutral loci that dominate the conservation genetics research agenda. We used RADseq to revisit earlier molecular studies of the IUCN Critically Endangered Magdalena River turtle (Podocnemis lewyana), documenting the conservation insights gained by increasing the number of neutral markers by several orders of magnitude. Earlier research indicated that P. lewyana has the lowest genetic diversity known for any chelonian, and little or no population differentiation among independent rivers. In contrast, the RADseq data revealed discrete population structure with isolation-by-distance within river segments and identified precise population breaks clearly delineating management units. It also confirmed that the species does not have extremely low heterozygosity and that effective population sizes are probably sufficient to maintain long-term evolutionary potential. Contrary to earlier inferences from more limited population genetic markers, our genomic data suggest that management strategies should shift from active genetic rescue to more passive protection without extreme interventions. We conclude with a list of examples of conservation studies in other vertebrates indicating that for many systems a genomic update is worth the investment.
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Affiliation(s)
- Natalia Gallego-García
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA.,Departamento de Ciencias Biológicas, Laboratorio de Ecología Molecular de Vertebrados Acuáticos LEMVA, Universidad de los Andes, Bogotá, Colombia
| | - Susana Caballero
- Departamento de Ciencias Biológicas, Laboratorio de Ecología Molecular de Vertebrados Acuáticos LEMVA, Universidad de los Andes, Bogotá, Colombia
| | - H Bradley Shaffer
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA.,La Kretz Center for California Conservation Science, and Institute of the Environment and Sustainability, University of California, Los Angeles, CA, USA
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11
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Chafin TK, Regmi B, Douglas MR, Edds DR, Wangchuk K, Dorji S, Norbu P, Norbu S, Changlu C, Khanal GP, Tshering S, Douglas ME. Parallel introgression, not recurrent emergence, explains apparent elevational ecotypes of polyploid Himalayan snowtrout. ROYAL SOCIETY OPEN SCIENCE 2021; 8:210727. [PMID: 34729207 PMCID: PMC8548808 DOI: 10.1098/rsos.210727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 10/01/2021] [Indexed: 06/13/2023]
Abstract
The recurrence of similar evolutionary patterns within different habitats often reflects parallel selective pressures acting upon either standing or independently occurring genetic variation to produce a convergence of phenotypes. This interpretation (i.e. parallel divergences within adjacent streams) has been hypothesized for drainage-specific morphological 'ecotypes' observed in polyploid snowtrout (Cyprinidae: Schizothorax). However, parallel patterns of differential introgression during secondary contact are a viable alternative hypothesis. Here, we used ddRADseq (N = 35 319 de novo and N = 10 884 transcriptome-aligned SNPs), as derived from Nepali/Bhutanese samples (N = 48 each), to test these competing hypotheses. We first employed genome-wide allelic depths to derive appropriate ploidy models, then a Bayesian approach to yield genotypes statistically consistent under the inferred expectations. Elevational 'ecotypes' were consistent in geometric morphometric space, but with phylogenetic relationships at the drainage level, sustaining a hypothesis of independent emergence. However, partitioned analyses of phylogeny and admixture identified subsets of loci under selection that retained genealogical concordance with morphology, suggesting instead that apparent patterns of morphological/phylogenetic discordance are driven by widespread genomic homogenization. Here, admixture occurring in secondary contact effectively 'masks' previous isolation. Our results underscore two salient factors: (i) morphological adaptations are retained despite hybridization and (ii) the degree of admixture varies across tributaries, presumably concomitant with underlying environmental or anthropogenic factors.
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Affiliation(s)
- Tyler K. Chafin
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder 80309, USA
| | - Binod Regmi
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA
- National Institute of Arthritis, Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health, Bethesda, MD 20892, USA
| | - Marlis R. Douglas
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA
| | - David R. Edds
- Department of Biological Sciences, Emporia State University, Emporia, KS 66801, USA
| | - Karma Wangchuk
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA
- National Research and Development Centre for Riverine and Lake Fisheries, Ministry of Agriculture and Forests, Royal Government of Bhutan, Haa, Bhutan
| | - Sonam Dorji
- National Research and Development Centre for Riverine and Lake Fisheries, Ministry of Agriculture and Forests, Royal Government of Bhutan, Haa, Bhutan
| | - Pema Norbu
- National Research and Development Centre for Riverine and Lake Fisheries, Ministry of Agriculture and Forests, Royal Government of Bhutan, Haa, Bhutan
| | - Sangay Norbu
- National Research and Development Centre for Riverine and Lake Fisheries, Ministry of Agriculture and Forests, Royal Government of Bhutan, Haa, Bhutan
| | - Changlu Changlu
- National Research and Development Centre for Riverine and Lake Fisheries, Ministry of Agriculture and Forests, Royal Government of Bhutan, Haa, Bhutan
| | - Gopal Prasad Khanal
- National Research and Development Centre for Riverine and Lake Fisheries, Ministry of Agriculture and Forests, Royal Government of Bhutan, Haa, Bhutan
| | - Singye Tshering
- National Research and Development Centre for Riverine and Lake Fisheries, Ministry of Agriculture and Forests, Royal Government of Bhutan, Haa, Bhutan
| | - Michael E. Douglas
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA
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12
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Burbrink FT, Ruane S. Contemporary Philosophy and Methods for Studying Speciation and Delimiting Species. ICHTHYOLOGY & HERPETOLOGY 2021. [DOI: 10.1643/h2020073] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Frank T. Burbrink
- Department of Herpetology, American Museum of Natural History, Central Park West at 79th Street, New York, New York 10024; . Send reprint requests to this address
| | - Sara Ruane
- Earth and Environmental Sciences: Ecology and Evolution, Rutgers University–Newark, 195 University Avenue, Newark, New Jersey 07102
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13
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Chafin TK, Zbinden ZD, Douglas MR, Martin BT, Middaugh CR, Gray MC, Ballard JR, Douglas ME. Spatial population genetics in heavily managed species: Separating patterns of historical translocation from contemporary gene flow in white-tailed deer. Evol Appl 2021; 14:1673-1689. [PMID: 34178112 PMCID: PMC8210790 DOI: 10.1111/eva.13233] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 03/10/2021] [Indexed: 01/16/2023] Open
Abstract
Approximately 100 years ago, unregulated harvest nearly eliminated white-tailed deer (Odocoileus virginianus) from eastern North America, which subsequently served to catalyze wildlife management as a national priority. An extensive stock-replenishment effort soon followed, with deer broadly translocated among states as a means of re-establishment. However, an unintended consequence was that natural patterns of gene flow became obscured and pretranslocation signatures of population structure were replaced. We applied cutting-edge molecular and biogeographic tools to disentangle genetic signatures of historical management from those reflecting spatially heterogeneous dispersal by evaluating 35,099 single nucleotide polymorphisms (SNPs) derived via reduced-representation genomic sequencing from 1143 deer sampled statewide in Arkansas. We then employed Simpson's diversity index to summarize ancestry assignments and visualize spatial genetic transitions. Using sub-sampled transects across these transitions, we tested clinal patterns across loci against theoretical expectations of their response under scenarios of re-colonization and restricted dispersal. Two salient results emerged: (A) Genetic signatures from historic translocations are demonstrably apparent; and (B) Geographic filters (major rivers; urban centers; highways) now act as inflection points for the distribution of this contemporary ancestry. These results yielded a statewide assessment of contemporary population structure in deer as driven by historic translocations as well as ongoing processes. In addition, the analytical framework employed herein to effectively decipher extant/historic drivers of deer distribution in Arkansas is also applicable for other biodiversity elements with similarly complex demographic histories.
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Affiliation(s)
- Tyler K. Chafin
- Department of Biological SciencesUniversity of ArkansasFayettevilleARUSA
- Present address:
Department of Ecology and Evolutionary BiologyUniversity of ColoradoBoulderCOUSA
| | - Zachery D. Zbinden
- Department of Biological SciencesUniversity of ArkansasFayettevilleARUSA
| | - Marlis R. Douglas
- Department of Biological SciencesUniversity of ArkansasFayettevilleARUSA
| | - Bradley T. Martin
- Department of Biological SciencesUniversity of ArkansasFayettevilleARUSA
| | | | - M. Cory Gray
- Research DivisionArkansas Game and Fish CommissionLittle RockARUSA
| | | | - Michael E. Douglas
- Department of Biological SciencesUniversity of ArkansasFayettevilleARUSA
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14
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García NC, Robinson WD. Current and Forthcoming Approaches for Benchmarking Genetic and Genomic Diversity. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.622603] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The current attrition of biodiversity extends beyond loss of species and unique populations to steady loss of a vast genomic diversity that remains largely undescribed. Yet the accelerating development of new techniques allows us to survey entire genomes ever faster and cheaper, to obtain robust samples from a diversity of sources including degraded DNA and residual DNA in the environment, and to address conservation efforts in new and innovative ways. Here we review recent studies that highlight the importance of carefully considering where to prioritize collection of genetic samples (e.g., organisms in rapidly changing landscapes or along edges of geographic ranges) and what samples to collect and archive (e.g., from individuals of little-known subspecies or populations, even of species not currently considered endangered). Those decisions will provide the sample infrastructure to detect the disappearance of certain genotypes or gene complexes, increases in inbreeding levels, and loss of genomic diversity as environmental conditions change. Obtaining samples from currently endangered, protected, and rare species can be particularly difficult, thus we also focus on studies that use new, non-invasive ways of obtaining genomic samples and analyzing them in these cases where other sampling options are highly constrained. Finally, biological collections archiving such samples face an inherent contradiction: their main goal is to preserve biological material in good shape so it can be used for scientific research for centuries to come, yet the technologies that can make use of such materials are advancing faster than collections can change their standardized practices. Thus, we also discuss current and potential new practices in biological collections that might bolster their usefulness for future biodiversity conservation research.
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15
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Martin BT, Chafin TK, Douglas MR, Placyk JS, Birkhead RD, Phillips CA, Douglas ME. The choices we make and the impacts they have: Machine learning and species delimitation in North American box turtles (Terrapene spp.). Mol Ecol Resour 2021; 21:2801-2817. [PMID: 33566450 DOI: 10.1111/1755-0998.13350] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 01/20/2021] [Accepted: 02/05/2021] [Indexed: 12/26/2022]
Abstract
Model-based approaches that attempt to delimit species are hampered by computational limitations as well as the unfortunate tendency by users to disregard algorithmic assumptions. Alternatives are clearly needed, and machine-learning (M-L) is attractive in this regard as it functions without the need to explicitly define a species concept. Unfortunately, its performance will vary according to which (of several) bioinformatic parameters are invoked. Herein, we gauge the effectiveness of M-L-based species-delimitation algorithms by parsing 64 variably-filtered versions of a ddRAD-derived SNP data set collected from North American box turtles (Terrapene spp.). Our filtering strategies included: (i) minor allele frequencies (MAF) of 5%, 3%, 1%, and 0% (= none), and (ii) maximum missing data per-individual/per-population at 25%, 50%, 75%, and 100% (= no filtering). We found that species-delimitation via unsupervised M-L impacted the signal-to-noise ratio in our data, as well as the discordance among resolved clades. The latter may also reflect biogeographic history, gene flow, incomplete lineage sorting, or combinations thereof (as corroborated from previously observed patterns of differential introgression). Our results substantiate M-L as a viable species-delimitation method, but also demonstrate how commonly observed patterns of phylogenetic discordance can seriously impact M-L-classification.
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Affiliation(s)
- Bradley T Martin
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA
| | - Tyler K Chafin
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA
| | - Marlis R Douglas
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA
| | - John S Placyk
- Department of Biology, University of Texas, Tyler, TX, USA.,Science Division, Trinity Valley Community College, Athens, Texas, USA
| | | | - Christopher A Phillips
- Illinois Natural History Survey, Prairie Research Institute, University of Illinois, Champaign, IL, USA
| | - Michael E Douglas
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA
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