1
|
Dadras H, Dadras F, Imentai A, Malinovskyi O, Pěnka T, Kolářová J, Policar T. Fine ultrastructural features of germ cells and spermatozoa during spermatogenesis in the European grayling, Thymallus thymallus (Teleostei, Salmoniformes, Salmonidae). Front Vet Sci 2023; 10:1188479. [PMID: 37323849 PMCID: PMC10267372 DOI: 10.3389/fvets.2023.1188479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 05/16/2023] [Indexed: 06/17/2023] Open
Abstract
This study aimed to examine the ultrastructure of spermatogenic stages and mature spermatozoa in the European grayling, Thymallus thymallus. The testes were examined microscopically with a transmission electron microscope to find out details of the structure and morphology of the grayling germ cells, spermatozoa and some somatic cells. The grayling testis has a tubular shape, with cysts or clusters of germ cells within seminiferous lobules. The spermatogenic cells, including spermatogonia, spermatocytes, and spermatids, can be found along seminiferous tubules. There are electron-dense bodies in germ cells from the primary spermatogonia to secondary spermatocyte stages. These undergo mitosis to reach the secondary spermatogonia stage, when they form primary and secondary spermatocytes. Spermatids undergo three different stages of differentiation during spermiogenesis, characterized by the level of chromatin condensation, elimination of cytoplasm, and the occurrence of the flagellum. The midpiece of spermatozoa is short and contains spherical or ovoid mitochondria. The sperm flagellum has an axoneme with nine doublets of peripheral microtubules and two central microtubules. The result of this study is valuable to be used as a standard reference for germ cell development, which is of great importance to get a clear insight into the process of grayling breeding practice.
Collapse
|
2
|
Kodela T, Jesenšek D, Sušnik Bajec S. Reproduction parameters of hatchery reared grayling (Thymallus thymallus) females. Anim Reprod Sci 2023; 249:107196. [PMID: 36680926 DOI: 10.1016/j.anireprosci.2023.107196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/16/2023] [Accepted: 01/16/2023] [Indexed: 01/19/2023]
Abstract
European grayling (Thymallus thymallus) is an endangered salmonid fish species and its populations have decreased considerably in European waters in recent decades. One of the conservation measures applied to grayling is stocking with hatchery-reared fish. To advance the knowledge of grayling reproduction in the hatchery, husbandry data were systematically collected in the period from 2006 to 2015 during grayling spawning seasons and analyzed to quantify grayling female reproductive parameters such as fecundity, egg size, and embryo survival to the eyed egg stage. Data was collected for first time spawners (3 years old) and repeat spawners reared in the hatchery. Statistically significant differences were found for the number of eggs between first time spawners, producing on average 3600 eggs, and repeat spawners, producing on average 8000 eggs. Absolute fecundity was positively correlated to grayling female total length and weight for both first time and repeat spawners. However, relative fecundity did not correlate with these parameters. A positive correlation was observed between female total length and mean egg weight for repeat spawners, while the correlation was negative for first time spawners. Heavier eggs tended to have a higher rate of survival until the eyed egg stage, though the correlation was stronger for first time spawners than for repeat spawners. Due to the higher reproductive success of repeat spawners, it could be concluded that larger and older grayling females should be included in hatchery reproduction.
Collapse
Affiliation(s)
- Tjaša Kodela
- Fisheries Research Institute of Slovenia, Spodnje Gameljne 61 a, 1211 Ljubljana-Šmartno, Slovenia
| | - Dušan Jesenšek
- Zavod Sara Vuri, Prekomorskih brigad 10, 5220 Tolmin, Slovenia
| | - Simona Sušnik Bajec
- University of Ljubljana, Biotechnical Faculty, Jamnikarjeva 101, 1000 Ljubljana, Slovenia.
| |
Collapse
|
3
|
Secci-Petretto G, Englmaier GK, Weiss SJ, Antonov A, Persat H, Denys GPJ, Schenekar T, Romanov VI, Taylor EB, Froufe E. Evaluating a species phylogeny using ddRAD SNPs: Cyto-nuclear discordance and introgression in the salmonid genus Thymallus (Salmonidae). Mol Phylogenet Evol 2023; 178:107654. [PMID: 36336233 DOI: 10.1016/j.ympev.2022.107654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 10/05/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022]
Abstract
Hybridization and introgression are very common among freshwater fishes due to the dynamic nature of hydrological landscapes. Cyclic patterns of allopatry and secondary contact provide numerous opportunities for interspecific gene flow, which can lead to discordant paths of evolution for mitochondrial and nuclear genomes. Here, we used double digest restriction-site associated DNA sequencing (ddRADseq) to obtain a genome-wide single nucleotide polymorphism (SNP) dataset comprehensive for allThymallus (Salmonidae)species to infer phylogenetic relationships and evaluate potential recent and historical gene flow among species. The newly obtained nuclear phylogeny was largely concordant with a previously published mitogenome-based topology but revealed a few cyto-nuclear discordances. These incongruencies primarily involved the placement of internal nodes rather than the resolution of species, except for one European species where anthropogenic stock transfers are thought to be responsible for the observed pattern. The analysis of four contact zones where multiple species are found revealed a few cases of mitochondrial capture and limited signals of nuclear introgression. Interestingly, the mechanisms restricting interspecific gene flow might be distinct; while in zones of secondary contact, small-scale physical habitat separation appeared as a limiting factor, biologically based reinforcement mechanisms are presumed to be operative in areas where species presumably evolved in sympatry. Signals of historical introgression were largely congruent with the routes of species dispersal previously inferred from mitogenome data. Overall, the ddRADseq dataset provided a robust phylogenetic reconstruction of the genus Thymallus including new insights into historical hybridization and introgression, opening up new questions concerning their evolutionary history.
Collapse
Affiliation(s)
- Giulia Secci-Petretto
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, S/N, 4450-208 Matosinhos, Portugal; Department of Biology, Faculty of Sciences, U. Porto - University of Porto, Portugal
| | - Gernot K Englmaier
- University of Graz, Institute of Biology, Universitätsplatz 2, 8010 Graz, Austria
| | - Steven J Weiss
- University of Graz, Institute of Biology, Universitätsplatz 2, 8010 Graz, Austria.
| | - Alexander Antonov
- Institute of Water and Ecological Problems, Far East Branch, Russian Academy of Sciences, ul. Kim Yu Chena 65, Khabarovsk, 680063 Russia
| | - Henri Persat
- Société Française d'Ichthyologie, Muséum National d'Histoire Naturelle Paris, France, 57 rue Cuvier CP26, 75005 Paris, France
| | - Gael P J Denys
- Unité Patrimoine Naturel - Centre d'expertise et de données (2006 OFB - CNRS - MNHN), Muséum national d'Histoire naturelle, 36 rue Geoffroy Saint-Hilaire CP 41, 75005 Paris, France; Biologie des organismes et écosystèmes aquatiques (BOREA 8067), MNHN, CNRS, IRD, SU, UCN, UA, 57 rue Cuvier CP26, 75005 Paris, France
| | - Tamara Schenekar
- University of Graz, Institute of Biology, Universitätsplatz 2, 8010 Graz, Austria
| | | | - Eric B Taylor
- Department of Zoology, Biodiversity Research Centre and Beaty Biodiversity Museum, University of British Columbia, 6270 University Blvd, Vancouver, BC V6T 1Z, Canada
| | - Elsa Froufe
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, S/N, 4450-208 Matosinhos, Portugal.
| |
Collapse
|
4
|
Application of high hydrostatic pressure (HHP) shock to induce triploid development in the European grayling (Thymallus thymallus L.). Anim Reprod Sci 2022; 237:106929. [DOI: 10.1016/j.anireprosci.2022.106929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 01/03/2022] [Accepted: 01/17/2022] [Indexed: 11/01/2022]
|
5
|
Weiss SJ, Gonçalves DV, Secci-Petretto G, Englmaier GK, Gomes-Dos-Santos A, Denys GPJ, Persat H, Antonov A, Hahn C, Taylor EB, Froufe E. Global systematic diversity, range distributions, conservation and taxonomic assessments of graylings (Teleostei: Salmonidae; Thymallus spp.). ORG DIVERS EVOL 2020. [DOI: 10.1007/s13127-020-00468-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
AbstractGraylings (Thymallus) are among the less well-studied groups of salmonid fishes, especially across their Asian distribution range. Here we perform a comprehensive global review of their phylogeography, systematic diversity and range distributions, including biogeographic reconstruction and assessment of both conservation and taxonomic status of each species. Based on a mitogenomic phylogenetic analysis, three approaches to the delineation of molecular operational units, and evaluation of 15 a-priori defined species, we provide biological support for the recognition of 13 grayling species, plus two additional species tentatively. Several instances of paraphyly and its potential effect on systematic inferences are discussed. Overall, the genus displays increasing species diversity and decreasing range size from higher to lower latitudes and ancestral trait reconstruction supports an East Asian origin for extant diversity, most likely centred in the Amur River drainage. Europe’s colonization by Thymallus took place as early as the late Miocene, at least two colonisations of North America are supported, and multiple dispersal events likely took place into Western Siberia. The conservation status for the 15 taxa was estimated to be: 6 least concern, 1 near-threatened, 2 vulnerable, 3 endangered and 3 data deficient.
Collapse
|
6
|
Palandačić A, Kruckenhauser L, Ahnelt H, Mikschi E. European minnows through time: museum collections aid genetic assessment of species introductions in freshwater fishes (Cyprinidae: Phoxinus species complex). Heredity (Edinb) 2020; 124:410-422. [PMID: 31896822 DOI: 10.1038/s41437-019-0292-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 12/18/2019] [Accepted: 12/18/2019] [Indexed: 11/09/2022] Open
Abstract
Massive fish introductions have taken place throughout much of the world, mostly over the last 70 years, and present a major threat to the genetic diversity of native fishes. Introductions have been reported for European Phoxinus, a ubiquitous small cyprinid that populates a wide variety of habitats. Species delineation in European Phoxinus has proven difficult with one reason being ranges of distribution that often traverse drainage boundaries. The present study combines recent samples with museum samples to better understand the current distribution of Phoxinus species and their distributions prior to the massive introductions of fishes in Europe, and to evaluate the use of museum specimens for species distribution studies. For these purposes, genetic lineages from sites collected prior to 1900 (n = 14), and between 1900 and 1950 (n = 8), were analysed using two mitochondrial and nuclear markers. Although possible fish introductions were detected, our results show that the distribution of genetic lineages of museum samples is comparable to that of the extant lineages of European Phoxinus present in those areas. These observations suggest that in the studied ranges the distribution of Phoxinus lineages has been driven by natural processes.
Collapse
Affiliation(s)
- Anja Palandačić
- First Zoological Department, Vienna Museum of Natural History, Burgring 7, 1010, Vienna, Austria.
| | - Luise Kruckenhauser
- Laboratory of Molecular Systematics, Vienna Museum of Natural History, Burgring 7, 1010, Vienna, Austria
| | - Harald Ahnelt
- First Zoological Department, Vienna Museum of Natural History, Burgring 7, 1010, Vienna, Austria.,Department of Theoretical Biology, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
| | - Ernst Mikschi
- First Zoological Department, Vienna Museum of Natural History, Burgring 7, 1010, Vienna, Austria
| |
Collapse
|
7
|
Weiss S, Secci‐Petretto G, Antonov A, Froufe E. Multiple species of grayling (Thymallussp.) found in sympatry in a remote tributary of the Amur River. ZOOL SCR 2019. [DOI: 10.1111/zsc.12393] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Steven Weiss
- Institute of Biology University of Graz Graz Austria
| | - Giulia Secci‐Petretto
- CIIMAR/CIMAR Interdisciplinary Centre of Marine and Environmental Research Terminal de Cruzeiros do Porto de Leixões University of Porto Matosinhos Portugal
- Department of Biology Faculty of Sciences U. Porto ‐ University of Porto Porto Portugal
| | - Alexander Antonov
- Institute of Water and Ecological Problems Far Eastern Division Russian Academy of Sciences Khabarovsk Russia
| | - Elsa Froufe
- CIIMAR/CIMAR Interdisciplinary Centre of Marine and Environmental Research Terminal de Cruzeiros do Porto de Leixões University of Porto Matosinhos Portugal
| |
Collapse
|
8
|
Kása E, Lujić J, Marinović Z, Kollár T, Bernáth G, Bokor Z, Urbányi B, Lefler KK, Jesenšek D, Horváth Á. Development of sperm vitrification protocols for two endangered salmonid species: the Adriatic grayling, Thymallus thymallus, and the marble trout, Salmo marmoratus. FISH PHYSIOLOGY AND BIOCHEMISTRY 2018; 44:1499-1507. [PMID: 29779063 DOI: 10.1007/s10695-018-0516-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 05/08/2018] [Indexed: 06/08/2023]
Abstract
Vitrification was applied to the sperm of two endangered fish species of Soča River basin in Slovenia, the Adriatic grayling (Thymallus thymallus) and marble trout (Salmo marmoratus) following testing different cooling devices and vitrifying media. Sperm was collected, diluted in species-specific non-activating media containing cryoprotectants, and vitrified by plunging directly into liquid nitrogen without pre-cooling. Progressive motility, curvilinear velocity, and straightness of fresh and vitrified-warmed sperm were evaluated with computer-assisted sperm analysis (CASA). Fertilization trials were carried out to test the effectiveness of vitrification in the case of grayling. A protocol utilizing a glucose-based extender, 30% cryoprotectants (15% methanol + 15% propylene glycol), 1:1 dilution ratio, and droplets of 2 μl on a Cryotop as cooling device yielded the highest post-thaw motility values for both Adriatic grayling (7.5 ± 6.5%) and marble trout (26.6 ± 15.8%). Viable embryos were produced by fertilizing eggs with vitrified grayling sperm (hatching 13.1 ± 11.7%, control hatching 73.9 ± 10.4%). The vitrification protocol developed in this study can be utilized in the conservation efforts for the two species as an alternative to slow-rate freezing when working in field conditions or when specific equipment necessary for slow-rate freezing is not available.
Collapse
Affiliation(s)
- Eszter Kása
- Department of Aquaculture, Szent István University, Páter Károly u. 1., Gödöllő, 2100, Hungary.
| | - Jelena Lujić
- Department of Aquaculture, Szent István University, Páter Károly u. 1., Gödöllő, 2100, Hungary
| | - Zoran Marinović
- Department of Aquaculture, Szent István University, Páter Károly u. 1., Gödöllő, 2100, Hungary
| | - Tímea Kollár
- Department of Aquaculture, Szent István University, Páter Károly u. 1., Gödöllő, 2100, Hungary
| | - Gergely Bernáth
- Department of Aquaculture, Szent István University, Páter Károly u. 1., Gödöllő, 2100, Hungary
| | - Zoltán Bokor
- Department of Aquaculture, Szent István University, Páter Károly u. 1., Gödöllő, 2100, Hungary
| | - Béla Urbányi
- Department of Aquaculture, Szent István University, Páter Károly u. 1., Gödöllő, 2100, Hungary
| | - Kinga Katalin Lefler
- Department of Aquaculture, Szent István University, Páter Károly u. 1., Gödöllő, 2100, Hungary
| | - Dušan Jesenšek
- Ribiška družina Tolmin, Trg 1. maja 7, 5220, Tolmin, Slovenia
| | - Ákos Horváth
- Department of Aquaculture, Szent István University, Páter Károly u. 1., Gödöllő, 2100, Hungary
| |
Collapse
|
9
|
Bajić A, Jojić V, Snoj A, Miljanović B, Askeyev O, Askeyev I, Marić S. Comparative body shape variation of the European grayling Thymallus thymallus (Actinopterygii, Salmonidae) from wild populations and hatcheries. ZOOL ANZ 2018. [DOI: 10.1016/j.jcz.2017.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
10
|
Carrera-García E, Rochard E, Acolas ML. Effects of rearing practice on post-release young-of-the-year behavior: Acipenser sturio early life in freshwater. ENDANGER SPECIES RES 2017. [DOI: 10.3354/esr00854] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
11
|
Ozerov MY, Gross R, Bruneaux M, Vähä JP, Burimski O, Pukk L, Vasemägi A. Genomewide introgressive hybridization patterns in wild Atlantic salmon influenced by inadvertent gene flow from hatchery releases. Mol Ecol 2016; 25:1275-93. [PMID: 26840557 DOI: 10.1111/mec.13570] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 01/13/2016] [Accepted: 01/26/2016] [Indexed: 12/26/2022]
Abstract
Many salmonid fish populations are threatened by genetic homogenization, primarily due to introgressive hybridization with hatchery-reared conspecifics. By applying genomewide analysis using two molecular marker types (1986 SNPs and 17 microsatellites), we assessed the genetic impacts of inadvertent gene flow via straying from hatchery releases on wild populations of Atlantic salmon in the Gulf of Finland, Baltic Sea, over 16 years (1996-2012). Both microsatellites and SNPs revealed congruent population genetic structuring, indicating that introgression changed the genetic make-up of wild populations by increasing genetic diversity and reducing genetic divergence. However, the degree of genetic introgression varied among studied populations, being higher in the eastern part and lower in the western part of Estonia, which most likely reflects the history of past stocking activities. Using kernel smoothing and permutation testing, we detected considerable heterogeneity in introgression patterns across the genome, with a large number of regions exhibiting nonrandom introgression widely dispersed across the genome. We also observed substantial variation in nonrandom introgression patterns within populations, as the majority of genomic regions showing elevated or reduced introgression were not consistently detected among temporal samples. This suggests that recombination, selection and stochastic processes may contribute to complex nonrandom introgression patterns. Our results suggest that (i) some genomic regions in Atlantic salmon are more vulnerable to introgressive hybridization, while others show greater resistance to unidirectional gene flow; and (ii) the hybridization of previously separated populations leads to complex and dynamic nonrandom introgression patterns that most likely have functional consequences for indigenous populations.
Collapse
Affiliation(s)
- M Y Ozerov
- Department of Biology, University of Turku, 20014, Turku, Finland.,Kevo Subarctic Research Institute, University of Turku, 20014, Turku, Finland
| | - R Gross
- Department of Aquaculture, Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, 51014, Tartu, Estonia
| | - M Bruneaux
- Department of Biology, University of Turku, 20014, Turku, Finland
| | - J-P Vähä
- Department of Biology, University of Turku, 20014, Turku, Finland.,Kevo Subarctic Research Institute, University of Turku, 20014, Turku, Finland
| | - O Burimski
- Department of Aquaculture, Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, 51014, Tartu, Estonia
| | - L Pukk
- Department of Aquaculture, Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, 51014, Tartu, Estonia
| | - A Vasemägi
- Department of Biology, University of Turku, 20014, Turku, Finland.,Department of Aquaculture, Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, 51014, Tartu, Estonia
| |
Collapse
|
12
|
Antognazza CM, Andreou D, Zaccara S, Britton RJ. Loss of genetic integrity and biological invasions result from stocking and introductions of Barbus barbus: insights from rivers in England. Ecol Evol 2016; 6:1280-92. [PMID: 26843923 PMCID: PMC4729780 DOI: 10.1002/ece3.1906] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 12/02/2015] [Accepted: 12/03/2015] [Indexed: 11/18/2022] Open
Abstract
Anthropogenic activities, including the intentional releases of fish for enhancing populations (stocking), are recognized as adversely impacting the adaptive potential of wild populations. Here, the genetic characteristics of European barbel Barbus barbus were investigated using 18 populations in England, where it is indigenous to eastern‐flowing rivers and where stocking has been used to enhance these populations. Invasive populations are also present in western‐flowing rivers following introductions of translocated fish. Two genetic clusters were evident in the indigenous range, centered on catchments in northeast and southeast England. However, stocking activities, including the release of hatchery‐reared fish, have significantly reduced the genetic differentiation across the majority of this range. In addition, in smaller indigenous rivers, populations appeared to mainly comprise fish of hatchery origin. In the nonindigenous range, genetic data largely aligned to historical stocking records, corroborating information that one particular river (Kennet) in southeast England was the original source of most invasive B. barbus in England. It is recommended that these genetic outputs inform management measures to either restore or maintain the original genetic diversity of the indigenous rivers, as this should help ensure populations can maintain their ability to adapt to changing environmental conditions. Where stocking is considered necessary, it is recommended that only broodstock from within the catchment is used.
Collapse
Affiliation(s)
- Caterina Maria Antognazza
- Department of Life and Environmental Sciences Bournemouth University BH12 5BB Poole Dorset UK; Dipartimento di Scienze Teoriche e Applicate Università degli Studi de ll'Insubria 21100 Varese Italy
| | - Demetra Andreou
- Department of Life and Environmental Sciences Bournemouth University BH12 5BB Poole Dorset UK
| | - Serena Zaccara
- Dipartimento di Scienze Teoriche e Applicate Università degli Studi dell'Insubria 21100 Varese Italy
| | - Robert J Britton
- Department of Life and Environmental Sciences Bournemouth University BH12 5BB Poole Dorset UK
| |
Collapse
|
13
|
Harvey AC, Glover KA, Taylor MI, Creer S, Carvalho GR. A common garden design reveals population-specific variability in potential impacts of hybridization between populations of farmed and wild Atlantic salmon, Salmo salar L. Evol Appl 2016; 9:435-49. [PMID: 26989435 PMCID: PMC4778114 DOI: 10.1111/eva.12346] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 11/13/2015] [Indexed: 11/30/2022] Open
Abstract
Released individuals can have negative impacts on native populations through various mechanisms, including competition, disease transfer and introduction of maladapted gene complexes. Previous studies indicate that the level of farmed Atlantic salmon introgression in native populations is population specific. However, few studies have explored the potential role of population diversity or river characteristics, such as temperature, on the consequences of hybridization. We compared freshwater growth of multiple families derived from two farmed, five wild and two F1 hybrid salmon populations at three contrasting temperatures (7°C, 12°C and 16°C) in a common garden experiment. As expected, farmed salmon outgrew wild salmon at all temperatures, with hybrids displaying intermediate growth. However, differences in growth were population specific and some wild populations performed better than others relative to the hybrid and farmed populations at certain temperatures. Therefore, the competitive balance between farmed and wild salmon may depend both on the thermal profile of the river and on the genetic characteristics of the respective farmed and wild strains. While limited to F1 hybridization, this study shows the merits in adopting a more complex spatially resolved approach to risk management of local populations.
Collapse
Affiliation(s)
- Alison C Harvey
- Molecular Ecology and Fisheries Genetics Laboratory School of Biological Sciences Bangor University Bangor UK
| | | | - Martin I Taylor
- Molecular Ecology and Fisheries Genetics Laboratory School of Biological Sciences Bangor University Bangor UK; School of Biological Sciences University of East Anglia Norwich UK
| | - Simon Creer
- Molecular Ecology and Fisheries Genetics Laboratory School of Biological Sciences Bangor University Bangor UK
| | - Gary R Carvalho
- Molecular Ecology and Fisheries Genetics Laboratory School of Biological Sciences Bangor University Bangor UK
| |
Collapse
|
14
|
Denton RD, Kenyon LJ, Greenwald KR, Gibbs HL. Evolutionary basis of mitonuclear discordance between sister species of mole salamanders (Ambystoma sp.). Mol Ecol 2014; 23:2811-24. [PMID: 24787951 DOI: 10.1111/mec.12775] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Revised: 04/07/2014] [Accepted: 04/16/2014] [Indexed: 11/29/2022]
Abstract
Distinct genetic markers should show similar patterns of differentiation between species reflecting their common evolutionary histories, yet there are increasing examples of differences in the biogeographic distribution of species-specific nuclear (nuDNA) and mitochondrial DNA (mtDNA) variants within and between species. Identifying the evolutionary processes that underlie these anomalous patterns of genetic differentiation is an important goal. Here, we analyse the putative mitonuclear discordance observed between sister species of mole salamanders (Ambystoma barbouri and A. texanum) in which A. barbouri-specific mtDNA is found in animals located within the range of A. texanum. We test three hypotheses for this discordance (undetected range expansion, mtDNA introgression, and hybridization) using nuDNA and mtDNA data analysed with methods that varied in the parameters estimated and the timescales measured. Results from a Bayesian clustering technique (structure), bidirectional estimates of gene flow (migrate-n and IMa2) and phylogeny-based methods (*beast, bucky) all support the conclusion that the discordance is due to geographically restricted mtDNA introgression from A. barbouri into A. texanum. Limited data on species-specific tooth morphology match this conclusion. Significant differences in environmental conditions exist between sites where A. texanum with and without A. barbouri-like mtDNA occur, suggesting a possible role for selection in the process of introgression. Overall, our study provides a general example of the value of using complimentary analyses to make inferences of the directionality, timescale, and source of mtDNA introgression in animals.
Collapse
Affiliation(s)
- Robert D Denton
- Department of Evolution, Ecology, and Organismal Biology, Ohio State University, Columbus, OH, 43210, USA
| | | | | | | |
Collapse
|
15
|
Valiquette E, Perrier C, Thibault I, Bernatchez L. Loss of genetic integrity in wild lake trout populations following stocking: insights from an exhaustive study of 72 lakes from Québec, Canada. Evol Appl 2014; 7:625-44. [PMID: 25067947 PMCID: PMC4105915 DOI: 10.1111/eva.12160] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 03/17/2014] [Indexed: 11/29/2022] Open
Abstract
Stocking represents the most important management tool worldwide to increase and sustain commercial and recreational fisheries in a context of overexploitation. Genetic impacts of this practice have been investigated in many studies, which examined population and individual admixture, but few have investigated determinants of these processes. Here, we addressed these questions from the genotyping at 19 microsatellite loci of 3341 adult lake trout (Salvelinus namaycush) from 72 unstocked and stocked lakes. Results showed an increase in genetic diversity and a twofold decrease in the extent of genetic differentiation among stocked populations when compared to unstocked. Stocked populations were characterized by significant admixture at both population and individual levels. Moreover, levels of admixture in stocked populations were strongly correlated with stocking intensity and a threshold value of total homogenization between source and stocked populations was identified. Our results also suggest that under certain scenarios, the genetic impacts of stocking could be of short duration. Overall, our study emphasizes the important alteration of the genetic integrity of stocked populations and the need to better understand determinants of admixture to optimize stocking strategies and to conserve the genetic integrity of wild populations.
Collapse
Affiliation(s)
- Eliane Valiquette
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval Québec, QC, Canada
| | - Charles Perrier
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval Québec, QC, Canada
| | - Isabel Thibault
- Ministère du Développement durable, de l'Environnement de la Faune et des Parcs Québec, QC, Canada
| | - Louis Bernatchez
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval Québec, QC, Canada
| |
Collapse
|
16
|
Meraner A, Cornetti L, Gandolfi A. Defining conservation units in a stocking-induced genetic melting pot: unraveling native and multiple exotic genetic imprints of recent and historical secondary contact in Adriatic grayling. Ecol Evol 2014; 4:1313-27. [PMID: 24834328 PMCID: PMC4020691 DOI: 10.1002/ece3.931] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 11/18/2013] [Accepted: 11/24/2013] [Indexed: 12/05/2022] Open
Abstract
The definition of conservation units is crucial for the sustainable management of endangered species, though particularly challenging when recent and past anthropogenic and natural gene flow might have played a role. The conservation of the European grayling, Thymallus thymallus, is particularly complex in its southern distribution area, where the Adriatic evolutionary lineage is endangered by a long history of anthropogenic disturbance, intensive stocking and potentially widespread genetic introgression. We provide mtDNA sequence and microsatellite data of 683 grayling from 30 sites of Adriatic as well as Danubian and Atlantic origin. We apply Bayesian clustering and Approximate Bayesian Computation (ABC) to detect microgeographic population structure and to infer the demographic history of the Adriatic populations, to define appropriate conservation units. Varying frequencies of indigenous genetic signatures of the Adriatic grayling were revealed, spanning from marginal genetic introgression to the collapse of native gene pools. Genetic introgression involved multiple exotic source populations of Danubian and Atlantic origin, thus evidencing the negative impact of few decades of stocking. Within the Adige River system, a contact zone of western Adriatic and eastern Danubian populations was detected, with ABC analyses suggesting a historical anthropogenic origin of eastern Adige populations, most likely founded by medieval translocations. Substantial river-specific population substructure within the Adriatic grayling Evolutionary Significant Unit points to the definition of different conservation units. We finally propose a catalog of management measures, including the legal prohibition of stocking exotic grayling and the use of molecular markers in supportive- and captive-breeding programs.
Collapse
Affiliation(s)
- Andreas Meraner
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach Via E. Mach 1, 38010, San Michele all'Adige, TN, Italy
| | - Luca Cornetti
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach Via E. Mach 1, 38010, San Michele all'Adige, TN, Italy
| | - Andrea Gandolfi
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach Via E. Mach 1, 38010, San Michele all'Adige, TN, Italy
| |
Collapse
|
17
|
Dantas HL, dos Santos Neto MA, Oliveira KKC, Severi W, Diniz FM, Coimbra MRM. Genetic Diversity of Captive and Wild Threatened CatfishPseudoplatystoma corruscansin the São Francisco River. ACTA ACUST UNITED AC 2013. [DOI: 10.1080/10641262.2013.800787] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
|
18
|
Amador C, Toro MÁ, Fernández J. Molecular markers allow to remove introgressed genetic background: a simulation study. PLoS One 2012; 7:e49409. [PMID: 23152901 PMCID: PMC3494676 DOI: 10.1371/journal.pone.0049409] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 10/10/2012] [Indexed: 11/25/2022] Open
Abstract
The maintenance of genetically differentiated populations can be important for several reasons (whether for wild species or domestic breeds of economic interest). When those populations are introgressed by foreign individuals, methods to eliminate the exogenous alleles can be implemented to recover the native genetic background. This study used computer simulations to explore the usefulness of several molecular based diagnostic approaches to recover of a native population after suffering an introgression event where some exogenous alleles were admixed for a few generations. To remove the exogenous alleles, different types of molecular markers were used in order to decide which of the available individuals contributed descendants to next generation and their number of offspring. Recovery was most efficient using diagnostic markers (i.e., with private alleles) and least efficient when using alleles present in both native and exogenous populations at different frequencies. The increased inbreeding was a side-effect of the management strategy. Both values (% of native alleles and inbreeding) were largely dependent on the amount of exogenous individuals entering the population and the number of generations of admixture that occurred prior to management.
Collapse
|
19
|
Lemer S, Planes S. Translocation of wild populations: conservation implications for the genetic diversity of the black-lipped pearl oyster Pinctada margaritifera. Mol Ecol 2012; 21:2949-62. [PMID: 22548374 DOI: 10.1111/j.1365-294x.2012.05588.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Translocation has been widely studied as a tool for conservation management to restore or enhance degraded populations. On the contrary, few studies have been conducted on translocation for commercial purposes. In this study, we evaluate the genetic consequences of translocation of wild individuals of Pinctada margaritifera on farmed and adjacent wild populations. We tested the hypotheses that translocations would induce high genetic heterogeneity in farmed populations and this heterogeneity would then leak into the adjacent wild populations. In fact, farmed samples exhibit high levels of heterogeneity and low pairwise relatedness compared to wild populations, highlighting the pooling of genetically divergent populations into farms. We also demonstrate that this heterogeneity is transmitted to adjacent wild populations as a result of interbreeding. Adjacent wild populations tend to have higher genetic diversity values and greater pairwise relatedness coefficient with farmed populations than wild populations. Overall, pearl culture in French Polynesia promotes the mixing of unrelated individuals in farmed locations and reduces genetic divergence among geographically distant populations as well as among farmed and wild populations of a same lagoon. We also studied for the first time a farmed population originating from spat collected in a lagoon where release of hatchery-produced larvae occurred 10 years ago and we were able to identify four distinct genetic groups. These groups contribute highly to reproduction and caused considerable genetic drift in the lagoon, suggesting that hatchery-produced larvae are neither sustainable method for pearl culture nor for conserving the diversity of P. margaritifera in French Polynesia.
Collapse
Affiliation(s)
- Sarah Lemer
- USR 3278 CRIOBE CNRS-EPHE, CBETM de l'Université de Perpignan, 66860 Perpignan Cedex, France.
| | | |
Collapse
|
20
|
|
21
|
Marie AD, Bernatchez L, Garant D. Empirical assessment of software efficiency and accuracy to detect introgression under variable stocking scenarios in brook charr (Salvelinus fontinalis). CONSERV GENET 2011. [DOI: 10.1007/s10592-011-0224-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
22
|
Marić S, Razpet A, Nikolić V, Simonović P. Genetic differentiation of European grayling (Thymallus thymallus) populations in Serbia, based on mitochondrial and nuclear DNA analyses. Genet Sel Evol 2011; 43:2. [PMID: 21235756 PMCID: PMC3036601 DOI: 10.1186/1297-9686-43-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Accepted: 01/14/2011] [Indexed: 12/05/2022] Open
Abstract
Background The structure and diversity of grayling (Thymallus thymallus) populations have been well studied in most of its native habitat; however the southernmost populations of the Balkan Peninsula remain largely unexplored. The purpose of this study was to assess the genetic diversity of Serbian grayling populations, detect the impact of stocking and provide guidelines for conservation and management. Methods Eighty grayling individuals were collected from four rivers (Ibar, Lim, Drina and Rzav). The mitochondrial DNA control region (CR; 595 bp of the 3'end and 74 bp of flanking tRNA) and the ATP6 gene (630 bp fragment) were sequenced for 20 individuals (five from each locality). In addition, all individuals were genotyped with 12 microsatellite loci. The diversity and structure of the populations as well as the recent and ancient population declines were studied using specialized software. Results We detected three new haplotypes in the mtDNA CR and four haplotypes in the ATP6 gene of which three had not been described before. Previously, one CR haplotype and two ATP6 gene haplotypes had been identified as allochthonous, originating from Slovenia. Reconstruction of phylogenetic relations placed the remaining two CR haplotypes from the River Danube drainage of Serbia into a new clade, which is related to the previously described sister Slovenian clade. These two clades form a new Balkan clade. Microsatellite marker analysis showed that all four populations are genetically distinct from each other without any sign of intra-population structure, although stocking of the most diverse population (Drina River) was confirmed by mtDNA analysis. Recent and historical population declines of Serbian grayling do not differ from those of other European populations. Conclusions Our study shows that (1) the Ibar, Lim and Drina Rivers grayling populations are genetically distinct from populations outside of Serbia and thus should be managed as native populations in spite of some introgression in the Drina River population and (2) the Rzav River population is not appropriate for further stocking activities since it originates from stocked Slovenian grayling. However, the Rzav River population does not represent an immediate danger to other populations because it is physically isolated from these.
Collapse
Affiliation(s)
- Saša Marić
- University of Belgrade, Faculty of Biology, Institute of Zoology, Studentski trg 16, 11001 Belgrade, Serbia.
| | | | | | | |
Collapse
|
23
|
Dawnay N, Dawnay L, Hughes RN, Cove R, Taylor MI. Substantial genetic structure among stocked and native populations of the European grayling (Thymallus thymallus, Salmonidae) in the United Kingdom. CONSERV GENET 2011. [DOI: 10.1007/s10592-010-0179-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
|
24
|
Pearse DE, Martinez E, Garza JC. Disruption of historical patterns of isolation by distance in coastal steelhead. CONSERV GENET 2010. [DOI: 10.1007/s10592-010-0175-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
25
|
Laikre L, Schwartz MK, Waples RS, Ryman N. Compromising genetic diversity in the wild: unmonitored large-scale release of plants and animals. Trends Ecol Evol 2010; 25:520-9. [DOI: 10.1016/j.tree.2010.06.013] [Citation(s) in RCA: 372] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 06/21/2010] [Accepted: 06/22/2010] [Indexed: 11/24/2022]
|
26
|
Hansen MM, Meier K, Mensberg KLD. Identifying footprints of selection in stocked brown trout populations: a spatio-temporal approach. Mol Ecol 2010; 19:1787-800. [PMID: 20345684 DOI: 10.1111/j.1365-294x.2010.04615.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Studies of interactions between farmed and wild salmonid fishes have suggested reduced fitness of farmed strains in the wild, but evidence for selection at the genic level is lacking. We studied three brown trout populations in Denmark which have been significantly admixed with stocked hatchery trout (19-64%), along with two hatchery strains used for stocking. The wild populations were represented by contemporary samples (2000-2006) and two of them by historical samples (1943-1956). We analysed 61 microsatellite loci, nine of which showed putative functional relationships [expressed sequence tag (EST)-linked or quantitative trait loci]. F(ST)-based outlier tests provided support for diversifying selection at chromosome regions marked by three loci, two anonymous and one EST-linked. Patterns of differentiation suggested that the loci were candidates for being under diversifying hitch-hiking selection in hatchery vs. wild environments. Analysis of hatchery strain admixture proportions showed that in one wild population, two of the loci showed significantly lower admixture proportions than the putatively neutral loci, implying contemporary selection against alleles introduced by hatchery strain trout. In the most strongly admixed population, however, there was no evidence for selection, possibly because of immigration by stocked trout overcoming selection against hatchery-derived alleles or supportive breeding practices allowing hatchery strain trout to escape natural selection. To our knowledge, this is the first study demonstrating footprints of selection in wild salmonid populations subject to spawning intrusion by farmed fish.
Collapse
Affiliation(s)
- Michael M Hansen
- Department of Biological Sciences, Aarhus University, Ny Munkegade 114, DK-8000 Aarhus C, Denmark.
| | | | | |
Collapse
|
27
|
Swatdipong A, Primmer CR, Vasemägi A. Historical and recent genetic bottlenecks in European grayling, Thymallus thymallus. CONSERV GENET 2009. [DOI: 10.1007/s10592-009-0031-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
|
28
|
Geist J, Kolahsa M, Gum B, Kuehn R. The importance of genetic cluster recognition for the conservation of migratory fish species: the example of the endangered European huchen Hucho hucho (L.). JOURNAL OF FISH BIOLOGY 2009; 75:1063-1078. [PMID: 20738598 DOI: 10.1111/j.1095-8649.2009.02377.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
European huchen Hucho hucho (L.) is an endangered flagship species, which is endemic to the Danube drainage in central Europe. To date, no genetic information has been available as a basis for ongoing conservation and breeding programmes for the species. It is suspected that most populations in the wild share one common gene pool and that they exclusively depend on stocking with hatchery fish. In this study, highly variable microsatellite markers were established and the genetic diversity and differentiation from four important hatchery-reared stocks were compared with that of eight H. hucho populations sampled in the wild. Overall, eight genetic clusters with a moderate to very great degree of genetic differentiation and high assignment rates were identified. Each cluster contained individuals from two to 10 different populations and 9-100% of specimens from hatchery stocks. It is proposed that genetic cluster-based management in the conservation of European huchen is advantageous compared with the consideration of single local populations. A combined approach of maintaining the evolutionary potential of wild populations and genetically variable hatchery stocks can maximize the conservation of the species' evolutionary potential.
Collapse
Affiliation(s)
- J Geist
- Unit of Functional Aquatic Ecology and Fish Biology, Department of Animal Science, Technische Universität München, D-85350 Freising, Germany
| | | | | | | |
Collapse
|
29
|
Swatdipong A, Vasemägi A, Koskinen MT, Piironen J, Primmer CR. Unanticipated population structure of European grayling in its northern distribution: implications for conservation prioritization. Front Zool 2009; 6:6. [PMID: 19331654 PMCID: PMC2676281 DOI: 10.1186/1742-9994-6-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Accepted: 03/30/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The European grayling (Thymallus thymallus) is a salmonid fish native to Europe, with a distribution ranging from England and France to the Ural Mountains of north-western Russia. The majority of grayling populations inhabit freshwater rivers and lakes but some populations also occupy brackish water in northern parts of the Baltic Sea. Previous population genetic studies have demonstrated that grayling populations in Finland, Estonia and Russia belong to a single mitochondrial lineage and exhibit high levels of differentiation even at a small geographic scale. As a result, we predicted that grayling populations should not cluster regionally. Despite the extensive amount of genetic research that has been carried out on grayling, comprehensive national-level information on population structure of grayling in Northern Europe is still lacking. Yet this is the level at which populations are currently managed. RESULTS We found unanticipated population structure of grayling clustering into three groups largely corresponding to the northern, Baltic and south-eastern geographic areas of Finland using 13 microsatellite loci. We also found a high level of genetic differentiation among the groups and moderate to high differentiation within the groups. This combined with low variability strongly indicates that genetic drift and limited migration have a major impact on grayling population structure. An allele size permutation test indicated that mutations at microsatellite loci have not significantly contributed to genetic differentiation among the three Finnish groups. However, at the European scale, mutations had significantly contributed to population differentiation. CONCLUSION This research provides novel genetic information on European grayling in its northern distribution range and has clear implications for supporting country-scale conservation efforts. Specifically, the strong between population divergence observed indicates that single populations should generally be recognized as separate management units. We also introduced an alternative prioritization strategy for population conservation based on the evaluation of the relative roles of different evolutionary forces shaping the gene pools. We envision that the proposed approach to categorize populations for conservation will be a useful tool for wildlife researchers and conservationists working on a diverse range of organisms.
Collapse
|
30
|
Kidd AG, Bowman J, Lesbarrères D, Schulte-Hostedde AI. Hybridization between escaped domestic and wild American mink (Neovison vison). Mol Ecol 2009; 18:1175-86. [PMID: 19243512 DOI: 10.1111/j.1365-294x.2009.04100.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The release of domesticated organisms into natural populations may adversely affect these populations through predation, resource competition, and the introduction of disease. Additionally, the potential for hybridization between wild and domestic conspecifics is of great concern because it can alter the evolutionary integrity of the affected populations. Wild American mink (Neovison vison) populations may be threatened not only by competition for resources with domestic mink originating from farms, but by breeding with such escapees. Using 10 microsatellite loci, we genotyped mink from Ontario, Canada, sampled from two farms, two putatively mixed populations in regions surrounding the mink farms, and two wild populations with no recent history of mink farming. Using individual-based Bayesian population assignment, we identified four population clusters, including one wild, and three domestic populations. The latter were not clustered by farm but rather by distinct line-bred colour phases. Population clustering also identified domestic and hybrid mink in the free-ranging populations. Nearly two-thirds of the mink sampled in the two putatively mixed populations (78% and 43%) were either farm escapees or descendants of escapees. Principal components analysis of allele frequencies supported our Bayesian assignment results. The power of our assignment test was assessed using simulated hybrid genotypes which suggested that our overall correct classification rate was 96.2%. The overwhelming presence of domestic animals and their hybridization with mink in natural populations is of great concern for the future sustainability of wild mink populations.
Collapse
Affiliation(s)
- A G Kidd
- Biology Department, Laurentian University, Sudbury, ON, Canada.
| | | | | | | |
Collapse
|
31
|
The selection of the 'wild': A combined molecular approach for the identification of pure indigenous fish from hybridised populations. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2007; 3:36-42. [PMID: 20483205 DOI: 10.1016/j.cbd.2007.02.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Revised: 02/20/2007] [Accepted: 02/21/2007] [Indexed: 11/23/2022]
Abstract
The identification of pure indigenous fish from hybridised populations represents a key issue in fisheries management and conservation biology. In the present study an approach for selection of purebred marble trout (Salmo trutta marmoratus C.) individuals out of admixed populations was set up and assessed. In a first step, baseline data sets of pure marble trout and pure brown trout specimens based on twelve microsatellite loci were used to simulate five consecutive generations of admixture. The baseline and the resulting simulation data sets were then combined with data of a 'real' hybridised marble trout population to perform a single individual assignment test as implemented in STRUCTURE. By this procedure the assignment approach was calibrated and it was possible to compare admixture coefficients obtained for individuals from different populations. The ranking of individual admixture coefficients on a plot and comparison with simulated data revealed that the test population was composed of pure marble trout individuals, first generation hybrids between marble trout and brown trout, and hybrid backcross specimens between both groups. However, by defining a critical q-value of 0.1 and additionally integrating individual sequence data of the mtDNA control region, it was possible to indicate individuals, which could be selected for the establishment of a pure marble trout strain.
Collapse
|
32
|
Vähä JP, Primmer CR. Efficiency of model-based Bayesian methods for detecting hybrid individuals under different hybridization scenarios and with different numbers of loci. Mol Ecol 2005; 15:63-72. [PMID: 16367830 DOI: 10.1111/j.1365-294x.2005.02773.x] [Citation(s) in RCA: 506] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Accurate detection of offspring resulting from hybridization between individuals of distinct populations has a range of applications in conservation and population genetics. We assessed the hybrid identification efficiency of two methods (implemented in the STRUCTURE and NEWHYBRIDS programs) which are tailored to identifying hybrid individuals but use different approaches. Simulated first- and second-generation hybrids were used to assess the performance of these two methods in detecting recent hybridization under scenarios with different levels of genetic divergence and varying numbers of loci. Despite the different approaches of the methods, the hybrid detection efficiency was generally similar and neither of the two methods outperformed the other in all scenarios assessed. Interestingly, hybrid detection efficiency was only minimally affected by whether reference population allele frequency information was included or not. In terms of genotyping effort, efficient detection of F1 hybrid individuals requires the use of 12 or 24 loci with pairwise F(ST) between hybridizing parental populations of 0.21 or 0.12, respectively. While achievable, these locus numbers are nevertheless higher than the number of loci currently commonly applied in population genetic studies. The method of STRUCTURE seemed to be less sensitive to the proportion of hybrids included in the sample, while NEWHYBRIDS seemed to perform slightly better when individuals from both backcross and F1 hybrid classes were present in the sample. However, separating backcrosses from purebred parental individuals requires a considerable genotyping effort (at least 48 loci), even when divergence between parental populations is high.
Collapse
Affiliation(s)
- Juha-Pekka Vähä
- Department of Biological and Environmental Sciences, PO Box 65, FIN-00014, University of Helsinki, Finland
| | | |
Collapse
|
33
|
Gum B, Gross R, Kuehn R. Mitochondrial and nuclear DNA phylogeography of European grayling (Thymallus thymallus): evidence for secondary contact zones in central Europe. Mol Ecol 2005; 14:1707-25. [PMID: 15836644 DOI: 10.1111/j.1365-294x.2005.02520.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mitochondrial and microsatellite DNA markers were applied to infer the phylogeography, intraspecific diversity and dynamics of the distributional history of European grayling (Thymallus thymallus) with focus on its central and northern European distribution range. Phylogenetic and nested clade analyses revealed at least four major mtDNA lineages, which evolved in geographical isolation during the Pleistocene. These lineages should be recognized as the basic evolutionary significant units (ESUs) for grayling in central and northern Europe. In addition, and in contrast to previous work on grayling, the results of Bayesian analysis of individual admixture coefficients, two-dimensional scaling analysis and spatial analysis of molecular variance provided evidence for a high level of admixture among major lineages in contact zones between drainages (e.g. the low mountain range of Germany), most likely resulting from glacial perturbations and ancient river connections between drainages during the Pleistocene glaciations. Even within river systems, a high level of differentiation among populations was revealed as indicated by the microsatellite data. Grayling sampled from 29 sites displayed high levels of differentiation (overall F(ST) = 0.367), a high number of private alleles and high bootstrap support for the genetic distance-based population clusters across 12 loci. We specifically discuss our results in context of phylogeograpic studies on other European freshwater fish species with habitat preferences similar to those of grayling. Our study shows that both large-scale phylogeographical and detailed genetic analyses on a fine scale are mandatory for developing appropriate conservation guidelines of endangered species.
Collapse
Affiliation(s)
- B Gum
- Wildlife Biology and Management Unit, Department for Ecosystem and Landscape Management, Technical University Munich-Weihenstephan, 85354 Freising, Germany.
| | | | | |
Collapse
|