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Moreno E, Cervantes I, Gutiérrez JP, Fernández I, Goyache F. Analysing the pedigree to identify undesirable losses of genetic diversity and to prioritize management decisions in captive breeding: a case study. Heredity (Edinb) 2024:10.1038/s41437-024-00723-z. [PMID: 39289561 DOI: 10.1038/s41437-024-00723-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 08/21/2024] [Accepted: 08/22/2024] [Indexed: 09/19/2024] Open
Abstract
When prevention of species extinction is the priority, captive breeding is a key component in conservation programmes, allowing the recording of pedigree information in studbooks. The genealogical information registered in Cuvier's gazelle studbook between 1975 and 2023 was analysed to (a) assess if the implemented mating policy was successful in preserving the genetic background of the founders (1 male:3 females) in the present population, and b) improve future management and breeding decisions. Although the maternal contribution of one founder female was lost and the mean inbreeding of the total live population was high (0.305 ± 0.095), the breeding policy applied produced better results than expected from a population starting from four founders. It was successful in keeping the individual increase in inbreeding low (0.047 ± 0.021), and, notably, the inbreeding tended to decrease during the last three decades of the breeding programme, ensuring the viability of this highly inbred population. Historical dissemination of individuals among the zoos of Europe and North America caused population structuring and genetic differentiation of the live North American population. However, it did not risk the viability of the captive population. The average relatedness coefficients allowed the identification of individuals with underrepresented genotypes, which is relevant to plan future mating guidelines to keep the founders' representation balanced in the next generations. This study highlights the importance of keeping long-term pedigree information to monitor changes in the genetic diversity of captive populations, which is crucial to implement optimal mating decisions and assuring their long-term viability within an ex situ conservation programme.
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Affiliation(s)
- Eulalia Moreno
- Departamento de Ecología Funcional y Evolutiva, Estación Experimental de Zonas Áridas (Consejo Superior de Investigaciones Científicas), Carretera de Sacramento s/n, La Cañada de San Urbano, Almería, E- 04120, Spain.
| | - Isabel Cervantes
- Departamento de Producción Animal, Universidad Complutense de Madrid, Avda. Puerta de Hierro s/n, Madrid, E-28040, Spain
| | - Juan Pablo Gutiérrez
- Departamento de Producción Animal, Universidad Complutense de Madrid, Avda. Puerta de Hierro s/n, Madrid, E-28040, Spain
| | - Iván Fernández
- SERIDA-Deva, Camino de Rioseco 1225, E-33394, Gijón (Asturias), Spain
| | - Félix Goyache
- SERIDA-Deva, Camino de Rioseco 1225, E-33394, Gijón (Asturias), Spain
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2
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Nagy I, Nguyen TA. Characterizing and Eliminating the Inbreeding Load. Vet Sci 2023; 11:8. [PMID: 38250914 PMCID: PMC10819885 DOI: 10.3390/vetsci11010008] [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: 10/29/2023] [Revised: 11/28/2023] [Accepted: 12/19/2023] [Indexed: 01/23/2024] Open
Abstract
The authors evaluated the relevant literature related to purging, which is the interaction between selection and inbreeding in which the population may eliminate its inbreeding load at least partially. According to the relevant literature, the inbreeding load and the process of purging were evaluated via pedigree methods based on ancestral inbreeding, the inbreeding-purging model, and expressed opportunity of purging, along with genomic methods. Most ancestral inbreeding-related studies were performed in zoos, where only a small proportion of the studied populations show signs of purging. The inbreeding-purging model was developed with Drosophila, and it was used to evaluate different zoo ungulates and Pannon white rabbits. Purging was detected in both studies. The expressed opportunity of purging was applied in Jersey cattle and Pannon white rabbits. In the Jersey cattle, it had an effect of 12.6% for fitness, while in the Pannon white rabbits, the inbreeding load was between 40% and 80% of its original value. The genomic studies also signalled purging, but they also made it clear that, contrary to the detected purging, the evaluated populations still suffered from inbreeding depression. Therefore, especially for domesticated animals, it can be concluded that deliberate inbreeding with the purpose of generating purging is not advocated.
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Affiliation(s)
- István Nagy
- Institute of Animal Sciences, Hungarian University of Agriculture and Life Sciences (MATE), Guba Sándor u. 40, 7400 Kaposvár, Hungary;
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3
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Analysis of Inbreeding Effects on Survival at Birth of Pannon White Rabbits Using the Inbreeding-Purging Model. DIVERSITY 2023. [DOI: 10.3390/d15010071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Mating between related animals is an inevitable consequence of a closed population structure especially when it coincides with a small population size. As a result, inbreeding depression may be encountered especially when considering fitness traits. However, under certain circumstances, the joint effects of inbreeding and selection may at least partly purge the detrimental genes from the population. In the course of this study, our objective was to determine the status of purging and to quantify the magnitude of the eliminated genetic load for the survival at birth of Pannon White rabbit kits maintained in a closed nucleus population. The evolution of the survival at birth was evaluated by applying the PurgeR R package based on the inbreeding-purging model. In the period from 1992 to 2017, 22.718 kindling records were analyzed. According to the heuristic approach, the purging coefficient reached the maximum possible value of 0.5 when estimating between 1992 and 1997. Based on the expected fitness over generations and on the expressed opportunity of purging, the beneficial effects of purging could be expected after 10 generations. The proportion of the purged genetic load could be between 20% and 60%. While the results obtained are not entirely conclusive, they do raise the possibility that some of the inbreeding load was caused, at least in part, by genes that could be successfully removed from the population by purging.
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Pérez‐Pereira N, López‐Cortegano E, García‐Dorado A, Caballero A. Prediction of fitness under different breeding designs in conservation programs. Anim Conserv 2022. [DOI: 10.1111/acv.12804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- N. Pérez‐Pereira
- Centro de Investigación Mariña Universidade de Vigo, Facultade de Bioloxía Vigo Spain
| | - E. López‐Cortegano
- Centro de Investigación Mariña Universidade de Vigo, Facultade de Bioloxía Vigo Spain
| | - A. García‐Dorado
- Departamento de Genética, Facultad de Ciencias Biológicas Universidad Complutense Madrid Spain
| | - A. Caballero
- Centro de Investigación Mariña Universidade de Vigo, Facultade de Bioloxía Vigo Spain
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Alvarez‐Estape M, Fontsere C, Serres‐Armero A, Kuderna LFK, Dobrynin P, Guidara H, Pukazhenthi BS, Koepfli K, Marques‐Bonet T, Moreno E, Lizano E. Insights from the rescue and breeding management of Cuvier's gazelle ( Gazella cuvieri) through whole-genome sequencing. Evol Appl 2022; 15:351-364. [PMID: 35386395 PMCID: PMC8965372 DOI: 10.1111/eva.13336] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 12/03/2021] [Indexed: 11/29/2022] Open
Abstract
Captive breeding programmes represent the most intensive type of ex situ population management for threatened species. One example is the Cuvier's gazelle programme that started in 1975 with only four founding individuals, and after more than four decades of management in captivity, a reintroduction effort was undertaken in Tunisia in 2016, to establish a population in an area historically included within its range. Here, we aim to determine the genetic consequences of this reintroduction event by assessing the genetic diversity of the founder stock as well as of their descendants. We present the first whole-genome sequencing dataset of 30 Cuvier's gazelles including captive-bred animals, animals born in Tunisia after a reintroduction and individuals from a genetically unrelated Moroccan population. Our analyses revealed no difference between the founder and the offspring cohorts in genome-wide heterozygosity and inbreeding levels, and in the amount and length of runs of homozygosity. The captive but unmanaged Moroccan gazelles have the lowest genetic diversity of all genomes analysed. Our findings demonstrate that the Cuvier's gazelle captive breeding programme can serve as source populations for future reintroductions of this species. We believe that this study can serve as a starting point for global applications of genomics to the conservation plan of this species.
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Affiliation(s)
| | | | | | | | - Pavel Dobrynin
- Computer Technologies LaboratoryITMO UniversitySt. PetersburgRussian Federation
- Center for Species SurvivalNational Zoological ParkSmithsonian Conservation Biology InstituteFront RoyalVirginiaUSA
- Center for Species SurvivalNational Zoological ParkSmithsonian Conservation Biology InstituteWashingtonDistrict of ColumbiaUSA
| | | | - Budhan S. Pukazhenthi
- Center for Species SurvivalNational Zoological ParkSmithsonian Conservation Biology InstituteFront RoyalVirginiaUSA
- Center for Species SurvivalNational Zoological ParkSmithsonian Conservation Biology InstituteWashingtonDistrict of ColumbiaUSA
| | - Klaus‐Peter Koepfli
- Computer Technologies LaboratoryITMO UniversitySt. PetersburgRussian Federation
- Center for Species SurvivalNational Zoological ParkSmithsonian Conservation Biology InstituteFront RoyalVirginiaUSA
- Center for Species SurvivalNational Zoological ParkSmithsonian Conservation Biology InstituteWashingtonDistrict of ColumbiaUSA
- Smithsonian‐Mason School of ConservationFront RoyalVirginiaUSA
| | - Tomas Marques‐Bonet
- Institute of Evolutionary Biology, (UPF‐CSIC)PRBBBarcelonaSpain
- CNAG‐CRGCentre for Genomic Regulation (CRG)Barcelona Institute of Science and Technology (BIST)BarcelonaSpain
- Universitat Autònoma de Barcelona (UAB)Edifici ICTA‐ICPInstitut Català de Paleontologia Miquel CrusafontBarcelonaSpain
- Catalan Institution of Research and Advanced Studies (ICREA)BarcelonaSpain
| | - Eulalia Moreno
- Dept. Ecología Funcional y EvolutivaEstación Experimental de Zonas Áridas‐CSICAlmeríaSpain
| | - Esther Lizano
- Institute of Evolutionary Biology, (UPF‐CSIC)PRBBBarcelonaSpain
- Universitat Autònoma de Barcelona (UAB)Edifici ICTA‐ICPInstitut Català de Paleontologia Miquel CrusafontBarcelonaSpain
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López-Cortegano E, Moreno E, García-Dorado A. Genetic purging in captive endangered ungulates with extremely low effective population sizes. Heredity (Edinb) 2021; 127:433-442. [PMID: 34584227 PMCID: PMC8551332 DOI: 10.1038/s41437-021-00473-2] [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: 03/17/2021] [Revised: 09/09/2021] [Accepted: 09/09/2021] [Indexed: 02/07/2023] Open
Abstract
Inbreeding threatens the survival of small populations by producing inbreeding depression, but also exposes recessive deleterious effects in homozygosis allowing for genetic purging. Using inbreeding-purging theory, we analyze early survival in four pedigreed captive breeding programs of endangered ungulates where population growth was prioritized so that most adult females were allowed to contribute offspring according to their fitness. We find evidence that purging can substantially reduce inbreeding depression in Gazella cuvieri (with effective population size Ne = 14) and Nanger dama (Ne = 11). No purging is detected in Ammotragus lervia (Ne = 4), in agreement with the notion that drift overcomes purging under fast inbreeding, nor in G. dorcas (Ne = 39) where, due to the larger population size, purging is slower and detection is expected to require more generations. Thus, although smaller populations are always expected to show smaller fitness (as well as less adaptive potential) than larger ones due to higher homozygosis and deleterious fixation, our results show that a substantial fraction of their inbreeding load and inbreeding depression can be purged when breeding contributions are governed by natural selection. Since management strategies intended to maximize the ratio from the effective to the actual population size tend to reduce purging, the search for a compromise between these strategies and purging could be beneficial in the long term. This could be achieved either by allowing some level of random mating and some role of natural selection in determining breeding contributions, or by undertaking reintroductions into the wild at the earliest opportunity.
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Affiliation(s)
- Eugenio López-Cortegano
- grid.4305.20000 0004 1936 7988Institute of Evolutionary Biology, University of Edinburgh, EH9 3FL Edinburgh, UK
| | - Eulalia Moreno
- grid.466639.80000 0004 0547 1725Estación Experimental de Zonas Áridas (CSIC), 04120 Almería, Spain
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Pérez-Pereira N, Pouso R, Rus A, Vilas A, López-Cortegano E, García-Dorado A, Quesada H, Caballero A. Long-term exhaustion of the inbreeding load in Drosophila melanogaster. Heredity (Edinb) 2021; 127:373-383. [PMID: 34400819 PMCID: PMC8478893 DOI: 10.1038/s41437-021-00464-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 07/29/2021] [Accepted: 07/29/2021] [Indexed: 02/07/2023] Open
Abstract
Inbreeding depression, the decline in fitness of inbred individuals, is a ubiquitous phenomenon of great relevance in evolutionary biology and in the fields of animal and plant breeding and conservation. Inbreeding depression is due to the expression of recessive deleterious alleles that are concealed in heterozygous state in noninbred individuals, the so-called inbreeding load. Genetic purging reduces inbreeding depression by removing these alleles when expressed in homozygosis due to inbreeding. It is generally thought that fast inbreeding (such as that generated by full-sib mating lines) removes only highly deleterious recessive alleles, while slow inbreeding can also remove mildly deleterious ones. However, a question remains regarding which proportion of the inbreeding load can be removed by purging under slow inbreeding in moderately large populations. We report results of two long-term slow inbreeding Drosophila experiments (125-234 generations), each using a large population and a number of derived lines with effective sizes about 1000 and 50, respectively. The inbreeding load was virtually exhausted after more than one hundred generations in large populations and between a few tens and over one hundred generations in the lines. This result is not expected from genetic drift alone, and is in agreement with the theoretical purging predictions. Computer simulations suggest that these results are consistent with a model of relatively few deleterious mutations of large homozygous effects and partially recessive gene action.
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Affiliation(s)
- Noelia Pérez-Pereira
- grid.6312.60000 0001 2097 6738Centro de Investigación Mariña, Universidade de Vigo, Facultade de Bioloxía, Vigo, Spain
| | - Ramón Pouso
- grid.6312.60000 0001 2097 6738Centro de Investigación Mariña, Universidade de Vigo, Facultade de Bioloxía, Vigo, Spain
| | - Ana Rus
- grid.6312.60000 0001 2097 6738Centro de Investigación Mariña, Universidade de Vigo, Facultade de Bioloxía, Vigo, Spain
| | - Ana Vilas
- grid.6312.60000 0001 2097 6738Centro de Investigación Mariña, Universidade de Vigo, Facultade de Bioloxía, Vigo, Spain
| | - Eugenio López-Cortegano
- grid.6312.60000 0001 2097 6738Centro de Investigación Mariña, Universidade de Vigo, Facultade de Bioloxía, Vigo, Spain ,grid.4305.20000 0004 1936 7988Present Address: Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Aurora García-Dorado
- grid.4795.f0000 0001 2157 7667Facultad de Ciencias Biológicas, Departamento de Genética, Universidad Complutense, Madrid, Spain
| | - Humberto Quesada
- grid.6312.60000 0001 2097 6738Centro de Investigación Mariña, Universidade de Vigo, Facultade de Bioloxía, Vigo, Spain
| | - Armando Caballero
- grid.6312.60000 0001 2097 6738Centro de Investigación Mariña, Universidade de Vigo, Facultade de Bioloxía, Vigo, Spain
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Moreno E, Jebali A, Espeso G, Benzal J. Reintroducing Cuvier’s gazelle. Better than expected from captive-bred founders. Glob Ecol Conserv 2020. [DOI: 10.1016/j.gecco.2020.e01094] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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9
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Curik I, Kövér G, Farkas J, Szendrő Z, Romvári R, Sölkner J, Nagy I. Inbreeding depression for kit survival at birth in a rabbit population under long-term selection. Genet Sel Evol 2020; 52:39. [PMID: 32640975 PMCID: PMC7346452 DOI: 10.1186/s12711-020-00557-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 06/26/2020] [Indexed: 01/01/2023] Open
Abstract
Background Accumulation of detrimental mutations in small populations leads to inbreeding depression of fitness traits and a higher frequency of genetic defects, thus increasing risk of extinction. Our objective was to quantify the magnitude of inbreeding depression for survival at birth, in a closed rabbit population under long-term selection. Methods We used an information theory-based approach and multi-model inference to estimate inbreeding depression and its purging with respect to the trait ‘kit survival at birth’ over a 25-year period in a closed population of Pannon White rabbits, by analysing 22,718 kindling records. Generalised linear mixed models based on the logit link function were applied, which take polygenic random effects into account. Results Our results indicated that inbreeding depression occurred during the period 1992–1997, based on significant estimates of the z-standardised classical inbreeding coefficient z.FL (CI95% − 0.12 to − 0.03) and of the new inbreeding coefficient of the litter z.FNEWL (CI95% − 0.13 to − 0.04) as well as a 59.2% reduction in contributing founders. Inbreeding depression disappeared during the periods 1997–2007 and 2007–2017. For the period 1992–1997, the best model resulted in a significantly negative standardised estimate of the new inbreeding coefficient of the litter and a significantly positive standardised estimate of Kalinowski’s ancestral inbreeding coefficient of the litter (CI95% 0.01 to 0.17), which indicated purging of detrimental load. Kindling season and parity had effects on survival at birth that differed across the three periods of 1992–1997, 1997–2007 and 2007–2017. Conclusions Our results support the existence of inbreeding depression and its purging with respect to kit survival at birth in this Pannon White rabbit population. However, we were unable to exclude possible confounding from the effects of parity and potentially other environmental factors during the study period, thus our results need to be extended and confirmed in other populations.
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Affiliation(s)
- Ino Curik
- Department of Animal Science, Faculty of Agriculture, University of Zagreb, Zagreb, Croatia.
| | - György Kövér
- Institute of Methodology, Faculty of Economic Science, Kaposvár University, Kaposvár, Hungary
| | - János Farkas
- Institute of Methodology, Faculty of Economic Science, Kaposvár University, Kaposvár, Hungary
| | - Zsolt Szendrő
- Institute of Animal Science, Faculty of Agricultural and Environmental Sciences, Kaposvár University, Kaposvár, Hungary
| | - Róbert Romvári
- Institute of Animal Science, Faculty of Agricultural and Environmental Sciences, Kaposvár University, Kaposvár, Hungary
| | - Johann Sölkner
- Division of Livestock Sciences, University of Natural Resources and Applied Life Sciences, Vienna, Austria
| | - Istvan Nagy
- Institute of Animal Science, Faculty of Agricultural and Environmental Sciences, Kaposvár University, Kaposvár, Hungary.
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Kubátová A, Štochlová K, Brandlová K, Jůnková Vymyslická P, Černá Bolfíková B. Comparison of divergent breeding management strategies in two species of semi-captive eland in Senegal. Sci Rep 2020; 10:8841. [PMID: 32483255 PMCID: PMC7264215 DOI: 10.1038/s41598-020-65598-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 05/06/2020] [Indexed: 11/18/2022] Open
Abstract
Breeding management of small populations may have a critical influence on the development of population characteristics in terms of levels of genetic diversity and inbreeding. Two populations of antelope sister species - Critically Endangered Western Derby eland (Tauroragus derbianus derbianus) and non-native Least Concern Cape eland (Taurotragus oryx oryx) bred under different management strategies were studied in Senegal, Western Africa. The aims of the study were to compare the population genetic parameters of the two species and to test for the presence of interspecific hybrids. In total, blood and tissue samples from 76 Western Derby elands and 26 Cape elands were investigated, using 12 microsatellite markers. No hybrid individuals were detected in the sampled animals within the multispecies enclosure in Bandia Reserve, Senegal. The parameters of genetic polymorphism indicated much lower genetic diversity in Western Derby elands compared to Cape elands. On the other hand, the coefficient of inbreeding was low in both species. It is hypothesized that this could be a positive effect of strict population management of Western Derby elands, which, despite the loss of genetic diversity, minimizes inbreeding.
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Affiliation(s)
- Anna Kubátová
- Department of Animal Science and Food Processing, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, Prague, Czech Republic
| | - Kateřina Štochlová
- Department of Animal Science and Food Processing, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, Prague, Czech Republic
| | - Karolína Brandlová
- Department of Animal Science and Food Processing, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, Prague, Czech Republic
| | - Pavla Jůnková Vymyslická
- Department of Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Prague, Czech Republic
| | - Barbora Černá Bolfíková
- Department of Animal Science and Food Processing, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, Prague, Czech Republic.
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Varona L, Altarriba J, Moreno C, Martínez-Castillero M, Casellas J. A multivariate analysis with direct additive and inbreeding depression load effects. Genet Sel Evol 2019; 51:78. [PMID: 31878872 PMCID: PMC6933709 DOI: 10.1186/s12711-019-0521-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 12/17/2019] [Indexed: 11/16/2022] Open
Abstract
Background Inbreeding is caused by mating between related individuals and its most common consequence is inbreeding depression. Several studies have detected heterogeneity in inbreeding depression among founder individuals, and recently a procedure for predicting hidden inbreeding depression loads associated with founders and the Mendelian sampling of non-founders has been developed. The objectives of our study were to expand this model to predict the inbreeding loads for all individuals in the pedigree and to estimate the covariance between the inbreeding loads and the additive genetic effects for the trait of interest. We tested the proposed approach with simulated data and with two datasets of records on weaning weight from the Spanish Pirenaica and Rubia Gallega beef cattle breeds. Results The posterior estimates of the variance components with the simulated datasets did not differ significantly from the simulation parameters. In addition, the correlation between the predicted and simulated inbreeding loads were always positive and ranged from 0.27 to 0.82. The beef cattle datasets comprised 35,126 and 75,194 records on weights between 170 and 250 days of age, and pedigrees of 308,836 and 384,434 individual-sire-dam entries for the Pirenaica and Rubia Gallega breeds, respectively. The posterior mean estimates of the variance of inbreeding depression loads were 29,967.8 and 28,222.4 for the Pirenaica and Rubia Gallega breeds, respectively. They were larger than those of the additive variance (695.0 and 439.8 for Pirenaica and Rubia Gallega, respectively), because they should be understood as the variance of the inbreeding depression achieved by a fully inbred (100%) descendant. Therefore, the inbreeding loads have to be rescaled for smaller inbreeding coefficients. In addition, a strong negative correlation (− 0.43 ± 0.10) between additive effects and inbreeding loads was detected in the Pirenaica, but not in the Rubia Gallega breed. Conclusions The results of the simulation study confirmed the ability of the proposed procedure to predict inbreeding depression loads for all individuals in the populations. Furthermore, the results obtained from the two real datasets confirmed the variability in the inbreeding depression loads in both breeds and suggested a negative correlation of the inbreeding loads with the additive genetic effects in the Pirenaica breed.
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Affiliation(s)
- Luis Varona
- Departamento de Anatomía Embriología y Genética Animal, Instituto Agroalimentario de Aragón (IA2), Universidad de Zaragoza, 50013, Saragossa, Spain.
| | - Juan Altarriba
- Departamento de Anatomía Embriología y Genética Animal, Instituto Agroalimentario de Aragón (IA2), Universidad de Zaragoza, 50013, Saragossa, Spain
| | - Carlos Moreno
- Departamento de Anatomía Embriología y Genética Animal, Instituto Agroalimentario de Aragón (IA2), Universidad de Zaragoza, 50013, Saragossa, Spain
| | - María Martínez-Castillero
- Dipartimento di Agronomia Animali, Alimenti Risorce Naturali e Ambiente, Università degli Studi di Padova, 35122, Padua, Italy
| | - Joaquim Casellas
- Departament de Ciència Animal i dels Aliments, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
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Malo AF, Gilbert TC, Riordan P. Drivers of sex ratio bias in the eastern bongo: lower inbreeding increases the probability of being born male. Proc Biol Sci 2019; 286:20190345. [PMID: 31064305 PMCID: PMC6532524 DOI: 10.1098/rspb.2019.0345] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 04/14/2019] [Indexed: 01/13/2023] Open
Abstract
Parent sex ratio allocation has consequences for individual fitness, population dynamics, and conservation. Theory predicts that parents should adjust offspring sex ratio when the fitness returns of producing male or female offspring varies. Previous studies have assumed that only mothers are capable of biasing offspring sex ratios, but have neglected fathers, given the expectation of an equal proportion of X- and Y-chromosome-bearing (CBS) sperm in ejaculates due to sex chromosome segregation at meiosis. This assumption has been recently refuted and both paternal fertility and paternal genetic quality have been shown to bias sex ratios. Here, we simultaneously test the relative contribution of paternal, maternal, and individual genetic quality, as measured by inbreeding, on the probability of being born a son or a daughter, using pedigree and lifelong offspring sex ratio data for the eastern bongo ( Tragelaphus eurycerus isaaci). Our models showed first, that surprisingly, as individual inbreeding decreases the probability of being born male increases, second, that paternal genetic effects on sex ratio were stronger than maternal genetic effects (which were absent). Furthermore, paternal effects were opposite in sign to those predicted; father inbreeding increases the probability of having sons. Previous paternal effects have been interpreted as adaptive due to sex-specific inbreeding depression for reproductive traits. We argue that in the eastern bongo, the opposite sign of the paternal effect on sex ratios results from a reversed sex-specific inbreeding depression pattern (present for female but not male reproductive traits). We anticipate that this research will help stimulate research on evolutionary constraints to sex ratios. Finally, the results open a new avenue of research to predict sex ratio allocation in an applied conservation context. Future models of sex ratio allocation should also include the predicted inbreeding level of the offspring and paternal inbreeding levels.
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Affiliation(s)
- Aurelio F. Malo
- GLOCEE - Global Change Ecology and Evolution Group, Department of Life Sciences, Universidad de Alcalá, 28871, Spain
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK
| | - Tania C. Gilbert
- Marwell Wildlife, Thompsons Lane, Winchester, Hampshire SO21 1JH, UK
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Philip Riordan
- Marwell Wildlife, Thompsons Lane, Winchester, Hampshire SO21 1JH, UK
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton SO17 1BJ, UK
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Lichtenauer W, van de Pol M, Cockburn A, Brouwer L. Indirect fitness benefits through extra-pair mating are large for an inbred minority, but cannot explain widespread infidelity among red-winged fairy-wrens. Evolution 2019; 73:467-480. [PMID: 30666623 PMCID: PMC7172280 DOI: 10.1111/evo.13684] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 12/30/2018] [Accepted: 01/03/2019] [Indexed: 11/30/2022]
Abstract
Extra‐pair paternity (EPP) has been suggested to improve the genetic quality of offspring, but evidence has been equivocal. Benefits of EPP may be only available to specific individuals or under certain conditions. Red‐winged fairy‐wrens have extremely high levels of EPP, suggesting fitness benefits might be large and available to most individuals. Furthermore, extreme philopatry commonly leads to incestuous social pairings, so inbreeding avoidance may be an important selection pressure. Here, we quantified the fitness benefits of EPP under varying conditions and across life‐stages. Extra‐pair offspring (EPO) did not appear to have higher fitness than within‐pair offspring (WPO), neither in poor years nor in the absence of helpers‐at‐the‐nest. However, EPP was beneficial for closely related social pairs, because inbred WPO suffered an overall 75% reduction in fitness. Inbreeding depression was nonlinear and reduced nestling body condition, first year survival and reproductive success. Our comprehensive study indicates that EPP should be favored for the 17% of females paired incestuously, but cannot explain the widespread infidelity in this species. Furthermore, our finding that fitness benefits of EPP only become apparent for a small part of the population could potentially explain the apparent absence of fitness differences in population wide comparisons of EPO and WPO.
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Affiliation(s)
- Wendy Lichtenauer
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia.,Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.,Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - Martijn van de Pol
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia.,Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands
| | - Andrew Cockburn
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Lyanne Brouwer
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia.,Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.,Department of Animal Ecology and Physiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, The Netherlands
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14
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Marchi N, Mennecier P, Georges M, Lafosse S, Hegay T, Dorzhu C, Chichlo B, Ségurel L, Heyer E. Close inbreeding and low genetic diversity in Inner Asian human populations despite geographical exogamy. Sci Rep 2018; 8:9397. [PMID: 29925873 PMCID: PMC6010435 DOI: 10.1038/s41598-018-27047-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 04/13/2018] [Indexed: 01/12/2023] Open
Abstract
When closely related individuals mate, they produce inbred offspring, which often have lower fitness than outbred ones. Geographical exogamy, by favouring matings between distant individuals, is thought to be an inbreeding avoidance mechanism; however, no data has clearly tested this prediction. Here, we took advantage of the diversity of matrimonial systems in humans to explore the impact of geographical exogamy on genetic diversity and inbreeding. We collected ethno-demographic data for 1,344 individuals in 16 populations from two Inner Asian cultural groups with contrasting dispersal behaviours (Turko-Mongols and Indo-Iranians) and genotyped genome-wide single nucleotide polymorphisms in 503 individuals. We estimated the population exogamy rate and confirmed the expected dispersal differences: Turko-Mongols are geographically more exogamous than Indo-Iranians. Unexpectedly, across populations, exogamy patterns correlated neither with the proportion of inbred individuals nor with their genetic diversity. Even more surprisingly, among Turko-Mongols, descendants from exogamous couples were significantly more inbred than descendants from endogamous couples, except for large distances (>40 km). Overall, 37% of the descendants from exogamous couples were closely inbred. This suggests that in Inner Asia, geographical exogamy is neither efficient in increasing genetic diversity nor in avoiding inbreeding, which might be due to kinship endogamy despite the occurrence of dispersal.
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Affiliation(s)
- Nina Marchi
- Eco-anthropologie et Ethnobiologie, UMR 7206 CNRS, MNHN, Univ Paris Diderot, Sorbonne Paris Cité, Sorbonne Universités, 75016, Paris, France.
| | - Philippe Mennecier
- Eco-anthropologie et Ethnobiologie, UMR 7206 CNRS, MNHN, Univ Paris Diderot, Sorbonne Paris Cité, Sorbonne Universités, 75016, Paris, France
| | - Myriam Georges
- Eco-anthropologie et Ethnobiologie, UMR 7206 CNRS, MNHN, Univ Paris Diderot, Sorbonne Paris Cité, Sorbonne Universités, 75016, Paris, France.,LM2E-UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, Institut Universitaire Européen de la Mer, Technopôle Brest-Iroise, Plouzane, 29280, France
| | - Sophie Lafosse
- Eco-anthropologie et Ethnobiologie, UMR 7206 CNRS, MNHN, Univ Paris Diderot, Sorbonne Paris Cité, Sorbonne Universités, 75016, Paris, France
| | - Tatyana Hegay
- Republican Scientific Center of Immunology, Ministry of Public Health, Tashkent, 100060, Uzbekistan
| | - Choduraa Dorzhu
- Department of biology and ecology, Tuvan State University, Kyzyl, 667000, Russia
| | - Boris Chichlo
- Eco-anthropologie et Ethnobiologie, UMR 7206 CNRS, MNHN, Univ Paris Diderot, Sorbonne Paris Cité, Sorbonne Universités, 75016, Paris, France
| | - Laure Ségurel
- Eco-anthropologie et Ethnobiologie, UMR 7206 CNRS, MNHN, Univ Paris Diderot, Sorbonne Paris Cité, Sorbonne Universités, 75016, Paris, France
| | - Evelyne Heyer
- Eco-anthropologie et Ethnobiologie, UMR 7206 CNRS, MNHN, Univ Paris Diderot, Sorbonne Paris Cité, Sorbonne Universités, 75016, Paris, France.
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15
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Todd ET, Ho SYW, Thomson PC, Ang RA, Velie BD, Hamilton NA. Founder-specific inbreeding depression affects racing performance in Thoroughbred horses. Sci Rep 2018; 8:6167. [PMID: 29670190 PMCID: PMC5906619 DOI: 10.1038/s41598-018-24663-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 04/05/2018] [Indexed: 11/18/2022] Open
Abstract
The Thoroughbred horse has played an important role in both sporting and economic aspects of society since the establishment of the breed in the 1700s. The extensive pedigree and phenotypic information available for the Thoroughbred horse population provides a unique opportunity to examine the effects of 300 years of selective breeding on genetic load. By analysing the relationship between inbreeding and racing performance of 135,572 individuals, we found that selective breeding has not efficiently alleviated the Australian Thoroughbred population of its genetic load. However, we found evidence for purging in the population that might have improved racing performance over time. Over 80% of inbreeding in the contemporary population is accounted for by a small number of ancestors from the foundation of the breed. Inbreeding to these ancestors has variable effects on fitness, demonstrating that an understanding of the distribution of genetic load is important in improving the phenotypic value of a population in the future. Our findings hold value not only for Thoroughbred and other domestic breeds, but also for small and endangered populations where such comprehensive information is not available.
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Affiliation(s)
- Evelyn T Todd
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia.
| | - Simon Y W Ho
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Peter C Thomson
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Rachel A Ang
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Brandon D Velie
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, 75007, Uppsala, Sweden
| | - Natasha A Hamilton
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
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Moreno E, Pérez-González J, Carranza J, Moya-Laraño J. Correction: Better Fitness in Captive Cuvier's Gazelle despite Inbreeding Increase: Evidence of Purging? PLoS One 2016; 11:e0152542. [PMID: 27010461 PMCID: PMC4806906 DOI: 10.1371/journal.pone.0152542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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