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Kenny D, Carthy TR, Murphy CP, Sleator RD, Evans RD, Berry DP. The Association Between Genomic Heterozygosity and Carcass Merit in Cattle. Front Genet 2022; 13:789270. [PMID: 35281838 PMCID: PMC8908906 DOI: 10.3389/fgene.2022.789270] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 01/25/2022] [Indexed: 12/16/2022] Open
Abstract
The objective of the present study was to quantify the association between both pedigree and genome-based measures of global heterozygosity and carcass traits, and to identify single nucleotide polymorphisms (SNPs) exhibiting non-additive associations with these traits. The carcass traits of interest were carcass weight (CW), carcass conformation (CC) and carcass fat (CF). To define the genome-based measures of heterozygosity, and to quantify the non-additive associations between SNPs and the carcass traits, imputed, high-density genotype data, comprising of 619,158 SNPs, from 27,213 cattle were used. The correlations between the pedigree-based heterosis coefficient and the three defined genomic measures of heterozygosity ranged from 0.18 to 0.76. The associations between the different measures of heterozygosity and the carcass traits were biologically small, with positive associations for CW and CC, and negative associations for CF. Furthermore, even after accounting for the pedigree-based heterosis coefficient of an animal, part of the remaining variability in some of the carcass traits could be captured by a genomic heterozygosity measure. This signifies that the inclusion of both a heterosis coefficient based on pedigree information and a genome-based measure of heterozygosity could be beneficial to limiting bias in predicting additive genetic merit. Finally, one SNP located on Bos taurus (BTA) chromosome number 5 demonstrated a non-additive association with CW. Furthermore, 182 SNPs (180 SNPs on BTA 2 and two SNPs on BTA 21) demonstrated a non-additive association with CC, while 231 SNPs located on BTA 2, 5, 11, 13, 14, 18, 19 and 21 demonstrated a non-additive association with CF. Results demonstrate that heterozygosity both at a global level and at the level of individual loci contribute little to the variability in carcass merit.
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Affiliation(s)
- David Kenny
- Animal and Grassland Research and Innovation Centre, Teagasc, Fermoy, Ireland
- Department of Biological Sciences, Munster Technological University, Cork, Ireland
| | - Tara R. Carthy
- Animal and Grassland Research and Innovation Centre, Teagasc Grange, Dunsany, Ireland
| | - Craig P. Murphy
- Department of Biological Sciences, Munster Technological University, Cork, Ireland
| | - Roy D. Sleator
- Department of Biological Sciences, Munster Technological University, Cork, Ireland
| | | | - Donagh P. Berry
- Animal and Grassland Research and Innovation Centre, Teagasc, Fermoy, Ireland
- *Correspondence: Donagh P. Berry,
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Villanueva B, Fernández A, Saura M, Caballero A, Fernández J, Morales-González E, Toro MA, Pong-Wong R. The value of genomic relationship matrices to estimate levels of inbreeding. Genet Sel Evol 2021; 53:42. [PMID: 33933002 PMCID: PMC8088726 DOI: 10.1186/s12711-021-00635-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 04/19/2021] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Genomic relationship matrices are used to obtain genomic inbreeding coefficients. However, there are several methodologies to compute these matrices and there is still an unresolved debate on which one provides the best estimate of inbreeding. In this study, we investigated measures of inbreeding obtained from five genomic matrices, including the Nejati-Javaremi allelic relationship matrix (FNEJ), the Li and Horvitz matrix based on excess of homozygosity (FL&H), and the VanRaden (methods 1, FVR1, and 2, FVR2) and Yang (FYAN) genomic relationship matrices. We derived expectations for each inbreeding coefficient, assuming a single locus model, and used these expectations to explain the patterns of the coefficients that were computed from thousands of single nucleotide polymorphism genotypes in a population of Iberian pigs. RESULTS Except for FNEJ, the evaluated measures of inbreeding do not match with the original definitions of inbreeding coefficient of Wright (correlation) or Malécot (probability). When inbreeding coefficients are interpreted as indicators of variability (heterozygosity) that was gained or lost relative to a base population, both FNEJ and FL&H led to sensible results but this was not the case for FVR1, FVR2 and FYAN. When variability has increased relative to the base, FVR1, FVR2 and FYAN can indicate that it decreased. In fact, based on FYAN, variability is not expected to increase. When variability has decreased, FVR1 and FVR2 can indicate that it has increased. Finally, these three coefficients can indicate that more variability than that present in the base population can be lost, which is also unreasonable. The patterns for these coefficients observed in the pig population were very different, following the derived expectations. As a consequence, the rate of inbreeding depression estimated based on these inbreeding coefficients differed not only in magnitude but also in sign. CONCLUSIONS Genomic inbreeding coefficients obtained from the diagonal elements of genomic matrices can lead to inconsistent results in terms of gain and loss of genetic variability and inbreeding depression estimates, and thus to misleading interpretations. Although these matrices have proven to be very efficient in increasing the accuracy of genomic predictions, they do not always provide a useful measure of inbreeding.
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Affiliation(s)
- Beatriz Villanueva
- Departamento de Mejora Genética Animal, INIA, Ctra. de La Coruña, km 7.5, 28040 Madrid, Spain
| | - Almudena Fernández
- Departamento de Mejora Genética Animal, INIA, Ctra. de La Coruña, km 7.5, 28040 Madrid, Spain
| | - María Saura
- Departamento de Mejora Genética Animal, INIA, Ctra. de La Coruña, km 7.5, 28040 Madrid, Spain
| | - Armando Caballero
- Centro de Investigación Mariña, Universidade de Vigo, Departamento de Bioquímica, Genética E Inmunología, Campus de Vigo, 36310 Vigo, Spain
| | - Jesús Fernández
- Departamento de Mejora Genética Animal, INIA, Ctra. de La Coruña, km 7.5, 28040 Madrid, Spain
| | | | - Miguel A. Toro
- Departamento de Producción Agraria, ETSI Agrónomos, Universidad Politécnica de Madrid, 28040 Madrid, Spain
| | - Ricardo Pong-Wong
- Genetics and Genomics, The Roslin Institute and the R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG UK
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Mancin E, Ablondi M, Mantovani R, Pigozzi G, Sabbioni A, Sartori C. Genetic Variability in the Italian Heavy Draught Horse from Pedigree Data and Genomic Information. Animals (Basel) 2020; 10:E1310. [PMID: 32751586 PMCID: PMC7460293 DOI: 10.3390/ani10081310] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 07/17/2020] [Accepted: 07/28/2020] [Indexed: 12/26/2022] Open
Abstract
This study aimed to investigate the genetic diversity in the Italian Heavy Horse Breed from pedigree and genomic data. Pedigree information for 64,917 individuals were used to assess inbreeding level, effective population size (Ne), and effective numbers of founders and ancestors (fa/fe). Genotypic information from SNP markers were available for 267 individuals of both sexes, and it allowed estimating genomic inbreeding in two methods (observed versus expected homozygosity and from ROH) to study the breed genomic structure and possible selection signatures. Pedigree and genomic inbreeding were greatly correlated (0.65 on average). The inbreeding trend increased over time, apart from periods in which the base population enlarged, when Ne increased also. Recent bottlenecks did not occur in the genome, as fa/fe have shown. The observed homozygosity results were on average lower than expected, which was probably due to the use of French Breton stallions to support the breed genetic variability. High homozygous regions suggested that inbreeding increased in different periods. Two subpopulations were distinguished, which was probably due to the different inclusion of French animals by breeders. Few selection signatures were found at the population level, with possible associations to disease resistance. The almost low inbreeding rate suggested that despite the small breed size, conservation actions are not yet required.
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Affiliation(s)
- Enrico Mancin
- Department of Agronomy, Food, Natural resources, Animals and Environment—DAFNAE, University of Padova, Viale dell’Università 16, 35020 Legnaro (PD), Italy; (E.M.); (C.S.)
| | - Michela Ablondi
- Dipartimento di Scienze Medico-Veterinarie, University of Parma Via del Taglio 10, 43126 Parma, Italy; (M.A.); (A.S.)
| | - Roberto Mantovani
- Department of Agronomy, Food, Natural resources, Animals and Environment—DAFNAE, University of Padova, Viale dell’Università 16, 35020 Legnaro (PD), Italy; (E.M.); (C.S.)
| | - Giuseppe Pigozzi
- Italian Heavy Draught Horse Breeders Association (ANACAITPR), 37068 Vigasio (VR), Italy;
| | - Alberto Sabbioni
- Dipartimento di Scienze Medico-Veterinarie, University of Parma Via del Taglio 10, 43126 Parma, Italy; (M.A.); (A.S.)
| | - Cristina Sartori
- Department of Agronomy, Food, Natural resources, Animals and Environment—DAFNAE, University of Padova, Viale dell’Università 16, 35020 Legnaro (PD), Italy; (E.M.); (C.S.)
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4
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Li W, Zhang M, Wang K, Lu Y, Tang H, Wu K. A double-labeling marker-based method for estimating inbreeding and parental genomic components in a population under conservation. ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES 2019; 33:12-23. [PMID: 31480193 PMCID: PMC6946976 DOI: 10.5713/ajas.19.0035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Accepted: 06/11/2019] [Indexed: 01/13/2023]
Abstract
Objective The objective of a conservation program is to maintain maximum genetic diversity and preserve the viability of a breed. However, the efficiency of a program is influenced by the ability to accurately measure and predict genetic diversity. Methods To examine this question, we conducted a simulation in which common measures (i.e. heterozygosity) and novel measures (identity-by-descent probabilities and parental genomic components) were used to estimate genetic diversity within a conserved population using double-labeled single nucleotide polymorphism markers. Results The results showed that the accuracy and sensitivity of identity-by-state probabilities and heterozygosity were close to identity by descent (IBD) probabilities, which reflect the true genetic diversity. Expected heterozygosity most closely aligned with IBD. All common measures suggested that practices used in the current Chinese pig conservation program result in a ~5% loss in genetic diversity every 10 generations. Parental genomic components were also analyzed to monitor real-time changes in genomic components for each male and female ancestor. The analysis showed that ~7.5% of male families and ~30% of female families were lost every 5 generations. After 50 generations of simulated conservation, 4 male families lost ~50% of their initial genomic components, and the genomic components for 24.8% of the female families were lost entirely. Conclusion In summary, compared with the true genetic diversity value obtained using double-labeled markers, expected heterozygosity appears to be the optimal indicator. Parental genomic components analysis provides a more detailed picture of genetic diversity and can be used to guide conservation management practices.
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Affiliation(s)
- Wenting Li
- College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China.,College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, China
| | - Mengmeng Zhang
- College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Kejun Wang
- College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, China
| | - Yunfeng Lu
- School of Life Science and Technology, Nanyang Normal University, Nanyang Henan, 473061, China
| | - Hui Tang
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an, 271018, China
| | - Keliang Wu
- College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
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5
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Eynard SE, Windig JJ, Hulsegge I, Hiemstra SJ, Calus MPL. The impact of using old germplasm on genetic merit and diversity-A cattle breed case study. J Anim Breed Genet 2018; 135:311-322. [PMID: 29808552 DOI: 10.1111/jbg.12333] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 04/17/2018] [Accepted: 04/18/2018] [Indexed: 01/09/2023]
Abstract
Artificial selection and high genetic gains in livestock breeds led to a loss of genetic diversity. Current genetic diversity conservation actions focus on long-term maintenance of breeds under selection. Gene banks play a role in such actions by storing genetic materials for future use and the recent development of genomic information is facilitating characterization of gene bank material for better use. Using the Meuse-Rhine-Issel Dutch cattle breed as a case study, we inferred the potential role of germplasm of old individuals for genetic diversity conservation of the current population. First, we described the evolution of genetic merit and diversity over time and then we applied the optimal contribution (OC) strategy to select individuals for maximizing genetic diversity, or maximizing genetic merit while constraining loss of genetic diversity. In the past decades, genetic merit increased while genetic diversity decreased. Genetic merit and diversity were both higher in an OC scenario restricting the rate of inbreeding when old individuals were considered for selection, compared to considering only animals from the current population. Thus, our study shows that gene bank material, in the form of old individuals, has the potential to support long-term maintenance and selection of breeds.
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Affiliation(s)
- Sonia E Eynard
- Wageningen University & Research Animal Breeding and Genomics, Wageningen, The Netherlands
- Centre for Genetic Resources the Netherlands, Wageningen University & Research, Wageningen, The Netherlands
- GABI, INRA, AgroParisTech, Université Paris-Saclay, Jouy en Josas, France
- GenPhySE, Université de Toulouse, INRA, INPT, INP-ENVT, Castanet Tolosan, France
| | - Jack J Windig
- Wageningen University & Research Animal Breeding and Genomics, Wageningen, The Netherlands
- Centre for Genetic Resources the Netherlands, Wageningen University & Research, Wageningen, The Netherlands
| | - Ina Hulsegge
- Wageningen University & Research Animal Breeding and Genomics, Wageningen, The Netherlands
- Centre for Genetic Resources the Netherlands, Wageningen University & Research, Wageningen, The Netherlands
| | - Sipke-Joost Hiemstra
- Centre for Genetic Resources the Netherlands, Wageningen University & Research, Wageningen, The Netherlands
| | - Mario P L Calus
- Wageningen University & Research Animal Breeding and Genomics, Wageningen, The Netherlands
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Doekes HP, Veerkamp RF, Bijma P, Hiemstra SJ, Windig JJ. Trends in genome-wide and region-specific genetic diversity in the Dutch-Flemish Holstein-Friesian breeding program from 1986 to 2015. Genet Sel Evol 2018; 50:15. [PMID: 29642838 PMCID: PMC5896142 DOI: 10.1186/s12711-018-0385-y] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 03/27/2018] [Indexed: 12/19/2022] Open
Abstract
Background In recent decades, Holstein–Friesian (HF) selection schemes have undergone profound changes, including the introduction of optimal contribution selection (OCS; around 2000), a major shift in breeding goal composition (around 2000) and the implementation of genomic selection (GS; around 2010). These changes are expected to have influenced genetic diversity trends. Our aim was to evaluate genome-wide and region-specific diversity in HF artificial insemination (AI) bulls in the Dutch-Flemish breeding program from 1986 to 2015. Methods Pedigree and genotype data (~ 75.5 k) of 6280 AI-bulls were used to estimate rates of genome-wide inbreeding and kinship and corresponding effective population sizes. Region-specific inbreeding trends were evaluated using regions of homozygosity (ROH). Changes in observed allele frequencies were compared to those expected under pure drift to identify putative regions under selection. We also investigated the direction of changes in allele frequency over time. Results Effective population size estimates for the 1986–2015 period ranged from 69 to 102. Two major breakpoints were observed in genome-wide inbreeding and kinship trends. Around 2000, inbreeding and kinship levels temporarily dropped. From 2010 onwards, they steeply increased, with pedigree-based, ROH-based and marker-based inbreeding rates as high as 1.8, 2.1 and 2.8% per generation, respectively. Accumulation of inbreeding varied substantially across the genome. A considerable fraction of markers showed changes in allele frequency that were greater than expected under pure drift. Putative selected regions harboured many quantitative trait loci (QTL) associated to a wide range of traits. In consecutive 5-year periods, allele frequencies changed more often in the same direction than in opposite directions, except when comparing the 1996–2000 and 2001–2005 periods. Conclusions Genome-wide and region-specific diversity trends reflect major changes in the Dutch-Flemish HF breeding program. Introduction of OCS and the shift in breeding goal were followed by a drop in inbreeding and kinship and a shift in the direction of changes in allele frequency. After introduction of GS, rates of inbreeding and kinship increased substantially while allele frequencies continued to change in the same direction as before GS. These results provide insight in the effect of breeding practices on genomic diversity and emphasize the need for efficient management of genetic diversity in GS schemes. Electronic supplementary material The online version of this article (10.1186/s12711-018-0385-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Harmen P Doekes
- Animal Breeding and Genomics, Wageningen University & Research, P.O. Box 338, 6700 AH, Wageningen, The Netherlands. .,Centre for Genetic Resources the Netherlands, Wageningen University & Research, P.O. Box 338, 6700 AH, Wageningen, The Netherlands.
| | - Roel F Veerkamp
- Animal Breeding and Genomics, Wageningen University & Research, P.O. Box 338, 6700 AH, Wageningen, The Netherlands
| | - Piter Bijma
- Animal Breeding and Genomics, Wageningen University & Research, P.O. Box 338, 6700 AH, Wageningen, The Netherlands
| | - Sipke J Hiemstra
- Centre for Genetic Resources the Netherlands, Wageningen University & Research, P.O. Box 338, 6700 AH, Wageningen, The Netherlands
| | - Jack J Windig
- Animal Breeding and Genomics, Wageningen University & Research, P.O. Box 338, 6700 AH, Wageningen, The Netherlands.,Centre for Genetic Resources the Netherlands, Wageningen University & Research, P.O. Box 338, 6700 AH, Wageningen, The Netherlands
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Which Individuals To Choose To Update the Reference Population? Minimizing the Loss of Genetic Diversity in Animal Genomic Selection Programs. G3-GENES GENOMES GENETICS 2018; 8:113-121. [PMID: 29133511 PMCID: PMC5765340 DOI: 10.1534/g3.117.1117] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Genomic selection (GS) is commonly used in livestock and increasingly in plant breeding. Relying on phenotypes and genotypes of a reference population, GS allows performance prediction for young individuals having only genotypes. This is expected to achieve fast high genetic gain but with a potential loss of genetic diversity. Existing methods to conserve genetic diversity depend mostly on the choice of the breeding individuals. In this study, we propose a modification of the reference population composition to mitigate diversity loss. Since the high cost of phenotyping is the limiting factor for GS, our findings are of major economic interest. This study aims to answer the following questions: how would decisions on the reference population affect the breeding population, and how to best select individuals to update the reference population and balance maximizing genetic gain and minimizing loss of genetic diversity? We investigated three updating strategies for the reference population: random, truncation, and optimal contribution (OC) strategies. OC maximizes genetic merit for a fixed loss of genetic diversity. A French Montbéliarde dairy cattle population with 50K SNP chip genotypes and simulations over 10 generations were used to compare these different strategies using milk production as the trait of interest. Candidates were selected to update the reference population. Prediction bias and both genetic merit and diversity were measured. Changes in the reference population composition slightly affected the breeding population. Optimal contribution strategy appeared to be an acceptable compromise to maintain both genetic gain and diversity in the reference and the breeding populations.
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8
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Intra-chromosomal estimates of inbreeding and coancestry in the Spanish Holstein cattle population. Livest Sci 2016. [DOI: 10.1016/j.livsci.2016.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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Monitoring of genetic diversity in Taiwan conserved chickens assessed by pedigree and molecular data. Livest Sci 2016. [DOI: 10.1016/j.livsci.2015.12.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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10
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Gómez-Romano F, Villanueva B, Fernández J, Woolliams JA, Pong-Wong R. The use of genomic coancestry matrices in the optimisation of contributions to maintain genetic diversity at specific regions of the genome. Genet Sel Evol 2016; 48:2. [PMID: 26763889 PMCID: PMC5518098 DOI: 10.1186/s12711-015-0172-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 11/19/2015] [Indexed: 11/10/2022] Open
Abstract
Background Optimal contribution methods have proved to be very efficient for controlling the rates at which coancestry and inbreeding increase and therefore, for maintaining genetic diversity. These methods have usually relied on pedigree information for estimating genetic relationships between animals. However, with the large amount of genomic information now available such as high-density single nucleotide polymorphism (SNP) chips that contain thousands of SNPs, it becomes possible to calculate more accurate estimates of relationships and to target specific regions in the genome where there is a particular interest in maximising genetic diversity. The objective of this study was to investigate the effectiveness of using genomic coancestry matrices for: (1) minimising the loss of genetic variability at specific genomic regions while restricting the overall loss in the rest of the genome; or (2) maximising the overall genetic diversity while restricting the loss of diversity at specific genomic regions. Results Our study shows that the use of genomic coancestry was very successful at minimising the loss of diversity and outperformed the use of pedigree-based coancestry (genetic diversity even increased in some scenarios). The results also show that genomic information allows a targeted optimisation to maintain diversity at specific genomic regions, whether they are linked or not. The level of variability maintained increased when the targeted regions were closely linked. However, such targeted management leads to an important loss of diversity in the rest of the genome and, thus, it is necessary to take further actions to constrain this loss. Optimal contribution methods also proved to be effective at restricting the loss of diversity in the rest of the genome, although the resulting rate of coancestry was higher than the constraint imposed. Conclusions The use of genomic matrices when optimising contributions permits the control of genetic diversity and inbreeding at specific regions of the genome through the minimisation of partial genomic coancestry matrices. The formula used to predict coancestry in the next generation produces biased results and therefore it is necessary to refine the theory of genetic contributions when genomic matrices are used to optimise contributions.
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Affiliation(s)
| | | | - Jesús Fernández
- Departamento de Mejora Genética Animal, INIA, Madrid, Spain.
| | - John A Woolliams
- The Roslin Institute and the R(D)SVS, University of Edinburgh, Edinburgh, UK
| | - Ricardo Pong-Wong
- The Roslin Institute and the R(D)SVS, University of Edinburgh, Edinburgh, UK
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Karimi K, Esmailizadeh Koshkoiyeh A, Asadi Fozi M, Porto-Neto LR, Gondro C. Prioritization for conservation of Iranian native cattle breeds based on genome-wide SNP data. CONSERV GENET 2015. [DOI: 10.1007/s10592-015-0762-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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12
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Saura M, Fernández A, Rodríguez MC, Toro MA, Barragán C, Fernández AI, Villanueva B. Genome-wide estimates of coancestry and inbreeding in a closed herd of ancient Iberian pigs. PLoS One 2013; 8:e78314. [PMID: 24205195 PMCID: PMC3814548 DOI: 10.1371/journal.pone.0078314] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 09/11/2013] [Indexed: 01/19/2023] Open
Abstract
Maintaining genetic variation and controlling the increase in inbreeding are crucial requirements in animal conservation programs. The most widely accepted strategy for achieving these objectives is to maximize the effective population size by minimizing the global coancestry obtained from a particular pedigree. However, for most natural or captive populations genealogical information is absent. In this situation, microsatellites have been traditionally the markers of choice to characterize genetic variation, and several estimators of genealogical coefficients have been developed using marker data, with unsatisfactory results. The development of high-throughput genotyping techniques states the necessity of reviewing the paradigm that genealogical coancestry is the best parameter for measuring genetic diversity. In this study, the Illumina PorcineSNP60 BeadChip was used to obtain genome-wide estimates of rates of coancestry and inbreeding and effective population size for an ancient strain of Iberian pigs that is now in serious danger of extinction and for which very accurate genealogical information is available (the Guadyerbas strain). Genome-wide estimates were compared with those obtained from microsatellite and from pedigree data. Estimates of coancestry and inbreeding computed from the SNP chip were strongly correlated with genealogical estimates and these correlations were substantially higher than those between microsatellite and genealogical coefficients. Also, molecular coancestry computed from SNP information was a better predictor of genealogical coancestry than coancestry computed from microsatellites. Rates of change in coancestry and inbreeding and effective population size estimated from molecular data were very similar to those estimated from genealogical data. However, estimates of effective population size obtained from changes in coancestry or inbreeding differed. Our results indicate that genome-wide information represents a useful alternative to genealogical information for measuring and maintaining genetic diversity.
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Affiliation(s)
- María Saura
- Departamento de Mejora Genética Animal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
| | - Almudena Fernández
- Departamento de Mejora Genética Animal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
| | - M. Carmen Rodríguez
- Departamento de Mejora Genética Animal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
| | - Miguel A. Toro
- Departamento de Producción Animal, Escuela Técnica Superior de Ingenieros Agrónomos, Madrid, Spain
| | - Carmen Barragán
- Departamento de Mejora Genética Animal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
| | - Ana I. Fernández
- Departamento de Mejora Genética Animal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
| | - Beatriz Villanueva
- Departamento de Mejora Genética Animal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
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13
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Engelsma KA, Veerkamp RF, Calus MPL, Windig JJ. Consequences for diversity when animals are prioritized for conservation of the whole genome or of one specific allele. J Anim Breed Genet 2013; 131:61-70. [PMID: 25099790 DOI: 10.1111/jbg.12052] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 07/15/2013] [Indexed: 11/29/2022]
Abstract
When animals are selected for one specific allele, for example for inclusion in a gene bank, this may result in the loss of diversity in other parts of the genome. The aim of this study was to quantify the risk of losing diversity across the genome when targeting a single allele for conservation when storing animals in a gene bank. From a small Holstein population, genotyped for 54,001 SNP loci, animals were prioritized for a single allele while maximizing the genomewide diversity using optimal contribution selection. Selection for a single allele was done for five different target frequencies: (i) no restriction on a target frequency; (ii) target frequency = original frequency in population; (iii) target frequency = 0.50; (iv) target frequency of the major allele = 1 (fixation); and (v) target frequency of the major allele = 0 (elimination). To do this, optimal contribution selection was extended with an extra constraint on the allele frequency of the target SNP marker. Results showed that elimination or fixation of alleles can result in substantial losses in genetic diversity around the targeted locus and also across the rest of the genome, depending on the allele frequency and the target frequency. It was concluded that losses of genetic diversity around the target allele are the largest when the target frequency is very different from the current allele frequency.
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Affiliation(s)
- K A Engelsma
- Wageningen UR Livestock Research, Animal Breeding and Genomics Centre, Lelystad, The Netherlands; Animal Breeding and Genomics Centre, Wageningen University, Wageningen, The Netherlands
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14
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Zhang L, Mousel MR, Wu X, Michal JJ, Zhou X, Ding B, Dodson MV, El-Halawany NK, Lewis GS, Jiang Z. Genome-wide genetic diversity and differentially selected regions among Suffolk, Rambouillet, Columbia, Polypay, and Targhee sheep. PLoS One 2013; 8:e65942. [PMID: 23762451 PMCID: PMC3677876 DOI: 10.1371/journal.pone.0065942] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 04/30/2013] [Indexed: 11/18/2022] Open
Abstract
Sheep are among the major economically important livestock species worldwide because the animals produce milk, wool, skin, and meat. In the present study, the Illumina OvineSNP50 BeadChip was used to investigate genetic diversity and genome selection among Suffolk, Rambouillet, Columbia, Polypay, and Targhee sheep breeds from the United States. After quality-control filtering of SNPs (single nucleotide polymorphisms), we used 48,026 SNPs, including 46,850 SNPs on autosomes that were in Hardy-Weinberg equilibrium and 1,176 SNPs on chromosome × for analysis. Phylogenetic analysis based on all 46,850 SNPs clearly separated Suffolk from Rambouillet, Columbia, Polypay, and Targhee, which was not surprising as Rambouillet contributed to the synthesis of the later three breeds. Based on pair-wise estimates of FST, significant genetic differentiation appeared between Suffolk and Rambouillet (FST = 0.1621), while Rambouillet and Targhee had the closest relationship (FST = 0.0681). A scan of the genome revealed 45 and 41 differentially selected regions (DSRs) between Suffolk and Rambouillet and among Rambouillet-related breed populations, respectively. Our data indicated that regions 13 and 24 between Suffolk and Rambouillet might be good candidates for evaluating breed differences. Furthermore, ovine genome v3.1 assembly was used as reference to link functionally known homologous genes to economically important traits covered by these differentially selected regions. In brief, our present study provides a comprehensive genome-wide view on within- and between-breed genetic differentiation, biodiversity, and evolution among Suffolk, Rambouillet, Columbia, Polypay, and Targhee sheep breeds. These results may provide new guidance for the synthesis of new breeds with different breeding objectives.
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Affiliation(s)
- Lifan Zhang
- Department of Animal Sciences, Washington State University, Pullman, Washington, United States of America
| | - Michelle R. Mousel
- USDA/ARS US Sheep Experiment Station, Dubois, Idaho, United States of America
| | - Xiaolin Wu
- Department of Dairy Science, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Jennifer J. Michal
- Department of Animal Sciences, Washington State University, Pullman, Washington, United States of America
| | - Xiang Zhou
- Department of Animal Sciences, Washington State University, Pullman, Washington, United States of America
| | - Bo Ding
- Department of Animal Sciences, Washington State University, Pullman, Washington, United States of America
| | - Michael V. Dodson
- Department of Animal Sciences, Washington State University, Pullman, Washington, United States of America
| | - Nermin K. El-Halawany
- Cell Biology Department, Division of Genetic Engineering and Biotechnology, National Research Center, Dokki, Gueza, Egypt
| | - Gregory S. Lewis
- USDA/ARS US Sheep Experiment Station, Dubois, Idaho, United States of America
| | - Zhihua Jiang
- Department of Animal Sciences, Washington State University, Pullman, Washington, United States of America
- * E-mail:
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15
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Woelders H, Windig J, Hiemstra SJ. How developments in cryobiology, reproductive technologies and conservation genomics could shape gene banking strategies for (farm) animals. Reprod Domest Anim 2013; 47 Suppl 4:264-73. [PMID: 22827380 DOI: 10.1111/j.1439-0531.2012.02085.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Many local breeds are currently at risk because of replacement by a limited number of specialized commercial breeds. Concurrently, for many breeds, allelic diversity within breeds declines because of inbreeding. Gene banking of germplasm may serve to secure the breeds and the alleles for any future use, for instance to recover a lost breed, to address new breeding goals, to support breeding schemes in small populations to minimize inbreeding, and for conservation genetics and genomics research. Developments in cryobiology and reproductive technology have generated several possibilities for preserving germplasm in farm animals. Furthermore, in some mammalian and bird species, gene banking of material is difficult or impossible, requiring development of new alternative methods or improvement of existing methods. Depending on the species, there are interesting possibilities or research developments in the use of epididymal spermatozoa, oocytes and embryos, ovarian and testicular tissue, primordial germ cells, and somatic cells for the conservation of genetic diversity in farm- and other animal species. Rapid developments in genomics research also provide new opportunities to optimize conservation and sampling strategies and to characterize genome-wide genetic variation. With regard to gene banks for farm animals, collaboration between European countries is being developed through a number of organizations, aimed at sharing knowledge and expertise between national programmes. It would be useful to explore further collaboration between countries, within the framework of a European gene banking strategy that should minimize costs of conservation and maximize opportunities for exploitation and sustainable use of genetic diversity.
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Affiliation(s)
- H Woelders
- Wageningen UR, Centre for Genetic Resources, CGN, Wageningen, The Netherlands.
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