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Damm E, Ullrich KK, Amos WB, Odenthal-Hesse L. Evolution of the recombination regulator PRDM9 in minke whales. BMC Genomics 2022; 23:212. [PMID: 35296233 PMCID: PMC8925151 DOI: 10.1186/s12864-022-08305-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 01/11/2022] [Indexed: 11/16/2022] Open
Abstract
Background PRDM9 is a key regulator of meiotic recombination in most metazoans, responsible for reshuffling parental genomes. During meiosis, the PRDM9 protein recognizes and binds specific target motifs via its array of C2H2 zinc-fingers encoded by a rapidly evolving minisatellite. The gene coding for PRDM9 is the only speciation gene identified in vertebrates to date and shows high variation, particularly in the DNA-recognizing positions of the zinc-finger array, within and between species. Across all vertebrate genomes studied for PRDM9 evolution, only one genome lacks variability between repeat types – that of the North Pacific minke whale. This study aims to understand the evolution and diversity of Prdm9 in minke whales, which display the most unusual genome reference allele of Prdm9 so far discovered in mammals. Results Minke whales possess all the features characteristic of PRDM9-directed recombination, including complete KRAB, SSXRD and SET domains and a rapidly evolving array of C2H2-type-Zincfingers (ZnF) with evidence of rapid evolution, particularly at DNA-recognizing positions that evolve under positive diversifying selection. Seventeen novel PRDM9 variants were identified within the Antarctic minke whale species, plus a single distinct PRDM9 variant in Common minke whales – shared across North Atlantic and North Pacific minke whale subspecies boundaries. Conclusion The PRDM9 ZnF array evolves rapidly, in minke whales, with at least one DNA-recognizing position under positive selection. Extensive PRDM9 diversity is observed, particularly in the Antarctic in minke whales. Common minke whales shared a specific Prdm9 allele across subspecies boundaries, suggesting incomplete speciation by the mechanisms associated with PRDM9 hybrid sterility. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08305-1.
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Affiliation(s)
- Elena Damm
- Department Evolutionary Genetics, Research Group Meiotic Recombination and Genome Instability, Max Planck Institute for Evolutionary Biology, August-Thienemann Str. 2, D-24306, Plön, Germany
| | - Kristian K Ullrich
- Department Evolutionary Genetics, Research Group Meiotic Recombination and Genome Instability, Max Planck Institute for Evolutionary Biology, August-Thienemann Str. 2, D-24306, Plön, Germany
| | - William B Amos
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Linda Odenthal-Hesse
- Department Evolutionary Genetics, Research Group Meiotic Recombination and Genome Instability, Max Planck Institute for Evolutionary Biology, August-Thienemann Str. 2, D-24306, Plön, Germany.
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2
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Adavoudi R, Pilot M. Consequences of Hybridization in Mammals: A Systematic Review. Genes (Basel) 2021; 13:50. [PMID: 35052393 PMCID: PMC8774782 DOI: 10.3390/genes13010050] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 12/14/2021] [Accepted: 12/20/2021] [Indexed: 12/18/2022] Open
Abstract
Hybridization, defined as breeding between two distinct taxonomic units, can have an important effect on the evolutionary patterns in cross-breeding taxa. Although interspecific hybridization has frequently been considered as a maladaptive process, which threatens species genetic integrity and survival via genetic swamping and outbreeding depression, in some cases hybridization can introduce novel adaptive variation and increase fitness. Most studies to date focused on documenting hybridization events and analyzing their causes, while relatively little is known about the consequences of hybridization and its impact on the parental species. To address this knowledge gap, we conducted a systematic review of studies on hybridization in mammals published in 2010-2021, and identified 115 relevant studies. Of 13 categories of hybridization consequences described in these studies, the most common negative consequence (21% of studies) was genetic swamping and the most common positive consequence (8%) was the gain of novel adaptive variation. The total frequency of negative consequences (49%) was higher than positive (13%) and neutral (38%) consequences. These frequencies are biased by the detection possibilities of microsatellite loci, the most common genetic markers used in the papers assessed. As negative outcomes are typically easier to demonstrate than positive ones (e.g., extinction vs hybrid speciation), they may be over-represented in publications. Transition towards genomic studies involving both neutral and adaptive variation will provide a better insight into the real impacts of hybridization.
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Affiliation(s)
| | - Małgorzata Pilot
- Museum and Institute of Zoology, Polish Academy of Sciences, ul. Nadwiślańska 108, 80-680 Gdańsk, Poland;
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3
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Nishimura F, Kim Y, Bando T, Fujise Y, Nakamura G, Murase H, Kato H. Morphological differences in skulls and feeding apparatuses between Antarctic (Balaenoptera bonaerensis) and common (Balaenoptera acutorostrata) minke whales, and the implication for their feeding ecology. CAN J ZOOL 2021. [DOI: 10.1139/cjz-2020-0237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The differences in rorqual feeding ecology have been linked to the presence of different morphological markers. The Antarctic minke whale (Balaenoptera bonaerensis Burmeister, 1867) and the common minke whale (Balaenoptera acutorostrata Lacépède, 1804) are closely related species, but their morphological differences have not been fully investigated. In this study, we compared 21 skull and 11 feeding apparatus (baleen and mouth-related parts) measurement points between these two species using hundreds of individuals covering a wide range of body lengths in both sexes. Their engulfment capacities were estimated using these measurements. Our results show that Antarctic minke whales have (i) proportionally larger skulls to the body length, (ii) more dorsoventrally and laterally curved rostra, (iii) proportionally larger feeding apparatuses to the condylobasal length, and (iv) significantly larger engulfment capacity than common minke whales. These differences could indicate that Antarctic minke whales have developed a feeding strategy suitable for feeding on krill, which forms large schools. In contrast, common minke whales have adapted to prey on small pelagic fishes that are agile and form small schools.
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Affiliation(s)
- F. Nishimura
- Laboratory of Cetacean Biology, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, Japan
| | - Y. Kim
- Laboratory of Cetacean Biology, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, Japan
| | - T. Bando
- Institute of Cetacean Research, Toyomi Shinko Building 5F, 4-5 Toyomi-cho, Chuo-ku, Tokyo 104-0055, Japan
| | - Y. Fujise
- Institute of Cetacean Research, Toyomi Shinko Building 5F, 4-5 Toyomi-cho, Chuo-ku, Tokyo 104-0055, Japan
| | - G. Nakamura
- Laboratory of Cetacean Biology, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, Japan
| | - H. Murase
- Laboratory of Cetacean Biology, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, Japan
| | - H. Kato
- Laboratory of Cetacean Biology, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, Japan
- Institute of Cetacean Research, Toyomi Shinko Building 5F, 4-5 Toyomi-cho, Chuo-ku, Tokyo 104-0055, Japan
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4
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New genetic evidences for distinct populations of the common minke whale (Balaenoptera acutorostrata) in the Southern Hemisphere. Polar Biol 2021. [DOI: 10.1007/s00300-021-02897-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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5
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Pampoulie C, Gíslason D, Ólafsdóttir G, Chosson V, Halldórsson SD, Mariani S, Elvarsson BÞ, Rasmussen MH, Iversen MR, Daníelsdóttir AK, Víkingsson GA. Evidence of unidirectional hybridization and second-generation adult hybrid between the two largest animals on Earth, the fin and blue whales. Evol Appl 2021; 14:314-321. [PMID: 33664778 PMCID: PMC7896702 DOI: 10.1111/eva.13091] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 08/04/2020] [Indexed: 11/30/2022] Open
Abstract
Biodiversity in the oceans has dramatically declined since the beginning of the industrial era, with accelerated loss of marine biodiversity impairing the ocean's capacity to maintain vital ecosystem services. A few organisms epitomize the damaging and long-lasting effects of anthropogenic exploitation: Some whale species, for instance, were brought to the brink of extinction, with their population sizes reduced to such low levels that may have caused a significant disruption to their reproductive dynamics and facilitated hybridization events. The incidence of hybridization is nevertheless believed to be rare, and very little information exists on its directionality. Here, using genetic markers, we show that all but one whale hybrid sample collected in Icelandic waters originated from the successful mating of male fin whale and female blue whale, thus suggesting unidirectional hybridization. We also demonstrate for the first time the existence of a second-generation adult (male) hybrid resulting from a backcross between a female hybrid and a pure male fin whale. The incidence of hybridization events between fin and blue whales is likely underestimated and the observed unidirectional hybridization (for F1 and F2 hybrids) is likely to induce a reproductive loss in blue whale, which may represent an additional challenge to its recovery in the Atlantic Ocean compared to other rorquals.
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Affiliation(s)
| | | | | | - Valérie Chosson
- Marine and Freshwater Research InstituteHafnarfjörðurIceland
| | | | - Stefano Mariani
- School of Biological and Environmental SciencesLiverpool John Moores UniversityLiverpoolUK
| | | | | | - Maria R. Iversen
- The University of Iceland’s Research Center in HúsavíkHúsavíkIceland
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6
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Gridley T, Elwen SH, Harris G, Moore DM, Hoelzel AR, Lampen F. Hybridization in bottlenose dolphins-A case study of Tursiops aduncus × T. truncatus hybrids and successful backcross hybridization events. PLoS One 2018; 13:e0201722. [PMID: 30208020 PMCID: PMC6135391 DOI: 10.1371/journal.pone.0201722] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 07/20/2018] [Indexed: 11/18/2022] Open
Abstract
The bottlenose dolphin, genus Tursiops is one of the best studied of all the Cetacea with a minimum of two species widely recognised. Common bottlenose dolphins (T. truncatus), are the cetacean species most frequently held in captivity and are known to hybridize with species from at least 6 different genera. In this study, we document several intra-generic hybridization events between T. truncatus and T. aduncus held in captivity. We demonstrate that the F1 hybrids are fertile and can backcross producing apparently healthy offspring, thereby showing introgressive inter-specific hybridization within the genus. We document that female F1 hybrids can reach sexual maturity at 4 yr and 3 mo of age, and can become pregnant and give birth before being fully weaned. The information presented has implications for understanding hybrid reticulation among cetacean species and practical implications for captive facilities housing either Tursiops species or hybrids thereof.
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Affiliation(s)
- T. Gridley
- Centre for Statistics in Ecology, Environment and Conservation, Department of Statistical Sciences, University of Cape Town, C/o Sea Search Research and Conservation NPC, Muizenberg Cape Town, South Africa
- * E-mail:
| | - S. H. Elwen
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, C/o Sea Search Research and Conservation NPC, Muizenberg Cape Town, South Africa
| | - G. Harris
- The South African Association for Marine Biological Research, uShaka Sea World, Point, Durban, South Africa
| | - D. M. Moore
- Department of Biosciences, Durham University, Durham, United Kingdom
| | - A. R. Hoelzel
- Department of Biosciences, Durham University, Durham, United Kingdom
| | - F. Lampen
- The South African Association for Marine Biological Research, uShaka Sea World, Point, Durban, South Africa
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7
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Malde K, Seliussen BB, Quintela M, Dahle G, Besnier F, Skaug HJ, Øien N, Solvang HK, Haug T, Skern-Mauritzen R, Kanda N, Pastene LA, Jonassen I, Glover KA. Whole genome resequencing reveals diagnostic markers for investigating global migration and hybridization between minke whale species. BMC Genomics 2017; 18:76. [PMID: 28086785 PMCID: PMC5237217 DOI: 10.1186/s12864-016-3416-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 12/12/2016] [Indexed: 11/24/2022] Open
Abstract
Background In the marine environment, where there are few absolute physical barriers, contemporary contact between previously isolated species can occur across great distances, and in some cases, may be inter-oceanic. An example of this can be seen in the minke whale species complex. Antarctic minke whales are genetically and morphologically distinct from the common minke found in the north Atlantic and Pacific oceans, and the two species are estimated to have been isolated from each other for 5 million years or more. Recent atypical migrations from the southern to the northern hemisphere have been documented and fertile hybrids and back-crossed individuals between both species have also been identified. However, it is not known whether this represents a contemporary event, potentially driven by ecosystem changes in the Antarctic, or a sporadic occurrence happening over an evolutionary time-scale. We successfully used whole genome resequencing to identify a panel of diagnostic SNPs which now enable us address this evolutionary question. Results A large number of SNPs displaying fixed or nearly fixed allele frequency differences among the minke whale species were identified from the sequence data. Five panels of putatively diagnostic markers were established on a genotyping platform for validation of allele frequencies; two panels (26 and 24 SNPs) separating the two species of minke whale, and three panels (22, 23, and 24 SNPs) differentiating the three subspecies of common minke whale. The panels were validated against a set of reference samples, demonstrating the ability to accurately identify back-crossed whales up to three generations. Conclusions This work has resulted in the development of a panel of novel diagnostic genetic markers to address inter-oceanic and global contact among the genetically isolated minke whale species and sub-species. These markers, including a globally relevant genetic reference data set for this species complex, are now openly available for researchers interested in identifying other potential whale hybrids in the world’s oceans. The approach used here, combining whole genome resequencing and high-throughput genotyping, represents a universal approach to develop similar tools for other species and population complexes. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3416-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ketil Malde
- Institute of Marine Research, PO box 1870, Nordnes, N-5817, Bergen, Norway.,Department of Informatics, University of Bergen, N-5020, Bergen, Norway
| | | | - María Quintela
- Institute of Marine Research, PO box 1870, Nordnes, N-5817, Bergen, Norway
| | - Geir Dahle
- Institute of Marine Research, PO box 1870, Nordnes, N-5817, Bergen, Norway
| | - Francois Besnier
- Institute of Marine Research, PO box 1870, Nordnes, N-5817, Bergen, Norway
| | - Hans J Skaug
- Institute of Marine Research, PO box 1870, Nordnes, N-5817, Bergen, Norway.,Department of Mathematics, University of Bergen, N-5020, Bergen, Norway
| | - Nils Øien
- Institute of Marine Research, PO box 1870, Nordnes, N-5817, Bergen, Norway
| | - Hiroko K Solvang
- Institute of Marine Research, PO box 1870, Nordnes, N-5817, Bergen, Norway
| | - Tore Haug
- Institute of Marine Research, PO box 6404, N-9294, Tromsø, Norway
| | | | - Naohisa Kanda
- Institute of Cetacean Research, Toyomi-cho 4-5, Chuo-ku, Tokyo, 104-0055, Japan.,Japan NUS Co., Ltd, Nishi-Shinjuku Kimuraya Bldg 5F, 7-5-25, Nishi-Shinjuku, 160-0023, Japan
| | - Luis A Pastene
- Institute of Cetacean Research, Toyomi-cho 4-5, Chuo-ku, Tokyo, 104-0055, Japan
| | - Inge Jonassen
- Department of Informatics, University of Bergen, N-5020, Bergen, Norway
| | - Kevin A Glover
- Institute of Marine Research, PO box 1870, Nordnes, N-5817, Bergen, Norway. .,Department of Biology, University of Bergen, N-5020, Bergen, Norway.
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8
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Miralles L, Oremus M, Silva MA, Planes S, Garcia-Vazquez E. Interspecific Hybridization in Pilot Whales and Asymmetric Genetic Introgression in Northern Globicephala melas under the Scenario of Global Warming. PLoS One 2016; 11:e0160080. [PMID: 27508496 PMCID: PMC4980017 DOI: 10.1371/journal.pone.0160080] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Accepted: 07/06/2016] [Indexed: 11/19/2022] Open
Abstract
Pilot whales are two cetacean species (Globicephala melas and G. macrorhynchus) whose distributions are correlated with water temperature and partially overlap in some areas like the North Atlantic Ocean. In the context of global warming, distribution range shifts are expected to occur in species affected by temperature. Consequently, a northward displacement of the tropical pilot whale G. macrorynchus is expected, eventually leading to increased secondary contact areas and opportunities for interspecific hybridization. Here, we describe genetic evidences of recurrent hybridization between pilot whales in northeast Atlantic Ocean. Based on mitochondrial DNA sequences and microsatellite loci, asymmetric introgression of G. macrorhynchus genes into G. melas was observed. For the latter species, a significant correlation was found between historical population growth rate estimates and paleotemperature oscillations. Introgressive hybridization, current temperature increases and lower genetic variation in G. melas suggest that this species could be at risk in its northern range. Under increasing environmental and human-mediated stressors in the North Atlantic Ocean, it seems recommendable to develop a conservation program for G. melas.
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Affiliation(s)
- Laura Miralles
- Department of Functional Biology, University of Oviedo, 33006, Oviedo, Spain
- * E-mail:
| | - Marc Oremus
- 16 rue Henri Niautou, 98800, Noumea, New Caledonia
| | - Mónica A. Silva
- MARE–Marine and Environmental Sciences Centre and Centre of IMAR- Institute of Marine Research, University of the Azores, 9901–862, Horta, Portugal
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, United States of America
| | - Serge Planes
- Laboratoire d’Excellence “CORAIL”, Centre de Recherche Insulaire et Observatoire de l'Environnement (CRIOBE), USR 3278 CNRS-EPHE-UPVD, BP 1013 Papetoai, 98729, Moorea, Polynésie Française
| | - Eva Garcia-Vazquez
- Department of Functional Biology, University of Oviedo, 33006, Oviedo, Spain
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9
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Jančúchová-Lásková J, Landová E, Frynta D. Experimental Crossing of Two Distinct Species of Leopard Geckos, Eublepharis angramainyu and E. macularius: Viability, Fertility and Phenotypic Variation of the Hybrids. PLoS One 2015; 10:e0143630. [PMID: 26633648 PMCID: PMC4669172 DOI: 10.1371/journal.pone.0143630] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 11/07/2015] [Indexed: 12/01/2022] Open
Abstract
Hybridization between distinct species of animals and subsequent genetic introgression plays a considerable role in the speciation process and the emergence of adaptive characters. Fitness of between-species hybrids usually sharply decreases with the divergence time of the concerned species and the divergence depth, which still allows for a successful crossing differs among principal clades of vertebrates. Recently, a review of hybridization events among distinct lizard species revealed that lizards belong to vertebrates with a highly developed ability to hybridize. In spite of this, reliable reports of experimental hybridizations between genetically fairly divergent species are only exceptional. Here, we show the results of the crossing of two distinct allopatric species of eyelid geckos possessing temperature sex determination and lacking sex chromosomes: Eublepharis macularius distributed in Pakistan/Afghanistan area and E. angramainyu, which inhabits Mesopotamia and adjacent areas. We demonstrated that F1 hybrids were viable and fertile, and the introgression of E. angramainyu genes into the E. macularius genome can be enabled via a backcrossing. The examined hybrids (except those of the F2 generation) displayed neither malformations nor a reduced survival. Analyses of morphometric and coloration traits confirmed phenotypic distinctness of both parental species and their F1 hybrids. These findings contrast with long-term geographic and an evolutionary separation of the studied species. Thus, the occurrence of fertile hybrids of comparably divergent species, such as E. angramainyu and E. macularius, may also be expected in other taxa of squamates. This would violate the current estimates of species diversity in lizards.
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Affiliation(s)
| | - Eva Landová
- Department of Zoology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Daniel Frynta
- Department of Zoology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
- * E-mail:
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10
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Investigating population genetic structure in a highly mobile marine organism: the minke whale Balaenoptera acutorostrata acutorostrata in the North East Atlantic. PLoS One 2014; 9:e108640. [PMID: 25268591 PMCID: PMC4182549 DOI: 10.1371/journal.pone.0108640] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 08/04/2014] [Indexed: 11/19/2022] Open
Abstract
Inferring the number of genetically distinct populations and their levels of connectivity is of key importance for the sustainable management and conservation of wildlife. This represents an extra challenge in the marine environment where there are few physical barriers to gene-flow, and populations may overlap in time and space. Several studies have investigated the population genetic structure within the North Atlantic minke whale with contrasting results. In order to address this issue, we analyzed ten microsatellite loci and 331 bp of the mitochondrial D-loop on 2990 whales sampled in the North East Atlantic in the period 2004 and 2007-2011. The primary findings were: (1) No spatial or temporal genetic differentiations were observed for either class of genetic marker. (2) mtDNA identified three distinct mitochondrial lineages without any underlying geographical pattern. (3) Nuclear markers showed evidence of a single panmictic population in the NE Atlantic according STRUCTURE's highest average likelihood found at K = 1. (4) When K = 2 was accepted, based on the Evanno's test, whales were divided into two more or less equally sized groups that showed significant genetic differentiation between them but without any sign of underlying geographic pattern. However, mtDNA for these individuals did not corroborate the differentiation. (5) In order to further evaluate the potential for cryptic structuring, a set of 100 in silico generated panmictic populations was examined using the same procedures as above showing genetic differentiation between two artificially divided groups, similar to the aforementioned observations. This demonstrates that clustering methods may spuriously reveal cryptic genetic structure. Based upon these data, we find no evidence to support the existence of spatial or cryptic population genetic structure of minke whales within the NE Atlantic. However, in order to conclusively evaluate population structure within this highly mobile species, more markers will be required.
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11
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Brown AM, Kopps AM, Allen SJ, Bejder L, Littleford-Colquhoun B, Parra GJ, Cagnazzi D, Thiele D, Palmer C, Frère CH. Population differentiation and hybridisation of Australian snubfin (Orcaella heinsohni) and Indo-Pacific humpback (Sousa chinensis) dolphins in north-western Australia. PLoS One 2014; 9:e101427. [PMID: 24988113 PMCID: PMC4079686 DOI: 10.1371/journal.pone.0101427] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 06/06/2014] [Indexed: 12/02/2022] Open
Abstract
Little is known about the Australian snubfin (Orcaella heinsohni) and Indo-Pacific humpback (Sousa chinensis) dolphins (‘snubfin’ and ‘humpback dolphins’, hereafter) of north-western Australia. While both species are listed as ‘near threatened’ by the IUCN, data deficiencies are impeding rigorous assessment of their conservation status across Australia. Understanding the genetic structure of populations, including levels of gene flow among populations, is important for the assessment of conservation status and the effective management of a species. Using nuclear and mitochondrial DNA markers, we assessed population genetic diversity and differentiation between snubfin dolphins from Cygnet (n = 32) and Roebuck Bays (n = 25), and humpback dolphins from the Dampier Archipelago (n = 19) and the North West Cape (n = 18). All sampling locations were separated by geographic distances >200 km. For each species, we found significant genetic differentiation between sampling locations based on 12 (for snubfin dolphins) and 13 (for humpback dolphins) microsatellite loci (FST = 0.05–0.09; P<0.001) and a 422 bp sequence of the mitochondrial control region (FST = 0.50–0.70; P<0.001). The estimated proportion of migrants in a population ranged from 0.01 (95% CI 0.00–0.06) to 0.13 (0.03–0.24). These are the first estimates of genetic diversity and differentiation for snubfin and humpback dolphins in Western Australia, providing valuable information towards the assessment of their conservation status in this rapidly developing region. Our results suggest that north-western Australian snubfin and humpback dolphins may exist as metapopulations of small, largely isolated population fragments, and should be managed accordingly. Management plans should seek to maintain effective population size and gene flow. Additionally, while interactions of a socio-sexual nature between these two species have been observed previously, here we provide strong evidence for the first documented case of hybridisation between a female snubfin dolphin and a male humpback dolphin.
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Affiliation(s)
- Alexander M. Brown
- Murdoch University Cetacean Research Unit, School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia
- * E-mail:
| | - Anna M. Kopps
- Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, United Kingdom
- Marine Evolution and Conservation, Centre for Ecological and Evolutionary Studies, University of Groningen, Groningen, The Netherlands
| | - Simon J. Allen
- Murdoch University Cetacean Research Unit, School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia
| | - Lars Bejder
- Murdoch University Cetacean Research Unit, School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia
| | | | - Guido J. Parra
- Cetacean Ecology, Behaviour and Evolution Lab, School of Biological Sciences, Flinders University, Adelaide, South Australia, Australia
- South Australian Research and Development Institute, Adelaide, South Australia, Australia
| | - Daniele Cagnazzi
- Marine Ecology Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, New South Wales, Australia
| | - Deborah Thiele
- Fenner School of Environment & Society, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Carol Palmer
- Marine Ecosystems, Flora and Fauna Division, Department of Land Resource Management, Palmerston, Northern Territory, Australia
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Celine H. Frère
- GeneCology Research Centre, University of the Sunshine Coast, Maroochydore DC, Queensland, Australia
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12
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Proietti MC, Reisser J, Marins LF, Marcovaldi MA, Soares LS, Monteiro DS, Wijeratne S, Pattiaratchi C, Secchi ER. Hawksbill × loggerhead sea turtle hybrids at Bahia, Brazil: where do their offspring go? PeerJ 2014; 2:e255. [PMID: 24688839 PMCID: PMC3932845 DOI: 10.7717/peerj.255] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 01/11/2014] [Indexed: 11/20/2022] Open
Abstract
Hybridization between hawksbill (Eretmochelys imbricata) and loggerhead (Caretta caretta) breeding groups is unusually common in Bahia state, Brazil. Such hybridization is possible because hawksbill and loggerhead nesting activities overlap temporally and spatially along the coast of this state. Nevertheless, the destinations of their offspring are not yet known. This study is the first to identify immature hawksbill × loggerhead hybrids (n = 4) from this rookery by analyzing the mitochondrial DNA (mtDNA) of 157 immature turtles morphologically identified as hawksbills. We also compare for the first time modeled dispersal patterns of hawksbill, loggerhead, and hybrid offspring considering hatching season and oceanic phase duration of turtles. Particle movements varied according to season, with a higher proportion of particles dispersing southwards throughout loggerhead and hybrid hatching seasons, and northwards during hawksbill season. Hybrids from Bahia were not present in important hawksbill feeding grounds of Brazil, being detected only at areas more common for loggerheads. The genetic and oceanographic findings of this work indicate that these immature hybrids, which are morphologically similar to hawksbills, could be adopting behavioral traits typical of loggerheads, such as feeding in temperate waters of the western South Atlantic. Understanding the distribution, ecology, and migrations of these hybrids is essential for the development of adequate conservation and management plans.
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Affiliation(s)
- Maira C Proietti
- Instituto de Oceanografia, Universidade Federal do Rio Grande , Rio Grande , Brazil
| | - Julia Reisser
- School of Environmental Systems Engineering & Oceans Institute, University of Western Australia , Perth , Australia ; CSIRO Wealth from Oceans Flagship , Perth , Australia
| | - Luis F Marins
- Instituto de Ciências Biológicas, Universidade Federal do Rio Grande , Rio Grande , Brazil
| | | | - Luciano S Soares
- Archie Carr Center for Sea Turtle Research & Department of Biology, University of Florida, Gainesville , FL , USA
| | - Danielle S Monteiro
- Instituto de Oceanografia, Universidade Federal do Rio Grande , Rio Grande , Brazil ; Núcleo de Educação e Monitoramento Ambiental , Rio Grande , Brazil
| | - Sarath Wijeratne
- School of Environmental Systems Engineering & Oceans Institute, University of Western Australia , Perth , Australia
| | - Charitha Pattiaratchi
- School of Environmental Systems Engineering & Oceans Institute, University of Western Australia , Perth , Australia
| | - Eduardo R Secchi
- Núcleo de Educação e Monitoramento Ambiental , Rio Grande , Brazil
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