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Pacheco HA, Rossoni A, Cecchinato A, Peñagaricano F. Identification of runs of homozygosity associated with male fertility in Italian Brown Swiss cattle. Front Genet 2023; 14:1227310. [PMID: 37485336 PMCID: PMC10356982 DOI: 10.3389/fgene.2023.1227310] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 06/23/2023] [Indexed: 07/25/2023] Open
Abstract
Intensive selection for improved productivity has been accompanied by an increase in inbreeding rates and a reduction in genetic diversity. The increase in inbreeding tends to impact performance, especially fitness-related traits such as male fertility. Inbreeding can be monitored using runs of homozygosity (ROH), defined as contiguous lengths of homozygous genotypes observed in an individual's chromosome. The goal of this study was to evaluate the presence of ROH in Italian Brown Swiss cattle and assess its association with bull fertility. First, we evaluated the association between ROH and male fertility using 1,102 Italian Brown Swiss bulls with sire conception rate records and 572 K SNPs spanning the entire genome. Second, we split the entire population into 100 high-fertility and 100 low-fertility bulls to investigate the potential enrichment of ROH segments in the low-fertility group. Finally, we mapped the significant ROH regions to the bovine genome to identify candidate genes associated with sperm biology and male fertility. Notably, there was a negative association between bull fertility and the amount of homozygosity. Four different ROH regions located in chromosomes 6, 10, 11, and 24 were significantly overrepresented in low-fertility bulls (Fisher's exact test, p-value <0.01). Remarkably, these four genomic regions harbor many genes such as WDR19, RPL9, LIAS, UBE2K, DPF3, 5S-rRNA, 7SK, U6, and WDR7 that are related to sperm biology and male fertility. Overall, our findings suggest that inbreeding and increased homozygosity have a negative impact on male fertility in Italian Brown Swiss cattle. The quantification of ROH can contribute to minimizing the inbreeding rate and avoid its negative effect on fitness-related traits, such as male fertility.
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Affiliation(s)
- Hendyel A. Pacheco
- Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI, United States
| | | | - Alessio Cecchinato
- Department of Agronomy, Food, Natural Resources, Animals and Environment, University of Padova, Padua, Italy
| | - Francisco Peñagaricano
- Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI, United States
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Pilon B, Hinterneder K, Hay EHA, Fragomeni B. Inbreeding Calculated with Runs of Homozygosity Suggests Chromosome-Specific Inbreeding Depression Regions in Line 1 Hereford. Animals (Basel) 2021; 11:ani11113105. [PMID: 34827837 PMCID: PMC8614356 DOI: 10.3390/ani11113105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/19/2021] [Accepted: 10/25/2021] [Indexed: 01/12/2023] Open
Abstract
The goal of this study was to evaluate inbreeding in a closed beef cattle population and assess phenotype prediction accuracy using inbreeding information. Effects of inbreeding on average daily gain phenotype in the Line 1 Hereford cattle population were assessed in this study. Genomic data were used to calculate inbreeding based on runs of homozygosity (ROH), and pedigree information was used to calculate the probability of an allele being identical by descent. Prediction ability of phenotypes using inbreeding coefficients calculated based on pedigree information and runs of homozygosity over the whole genome was close to 0, even in the case of significant inbreeding coefficient effects. On the other hand, inbreeding calculated per individual chromosomes' ROH yielded higher accuracies of prediction. Additionally, including only ROH from chromosomes with higher predicting ability further increased prediction accuracy. Phenotype prediction accuracy, inbreeding depression, and the effects of chromosome-specific ROHs varied widely across the genome. The results of this study suggest that inbreeding should be evaluated per individual regions of the genome. Moreover, mating schemes to avoid inbreeding depression should focus more on specific ROH with negative effects. Finally, using ROH as added information may increase prediction of the genetic merit of animals in a genomic selection program.
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Affiliation(s)
- Bethany Pilon
- Department of Animal Science, University of Connecticut, Storrs, CT 06269, USA; (B.P.); (K.H.)
- College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Kelly Hinterneder
- Department of Animal Science, University of Connecticut, Storrs, CT 06269, USA; (B.P.); (K.H.)
- College of Veterinary Medicine, Lincoln Memorial University, Harrogate, TN 37752, USA
| | - El Hamidi A. Hay
- Fort Keogh Livestock and Range Research Laboratory, ARS, USDA, Miles City, MT 59301, USA;
| | - Breno Fragomeni
- Department of Animal Science, University of Connecticut, Storrs, CT 06269, USA; (B.P.); (K.H.)
- Institute for System Genomics, University of Connecticut, Storrs, CT 06269, USA
- Correspondence:
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Makanjuola BO, Maltecca C, Miglior F, Marras G, Abdalla EA, Schenkel FS, Baes CF. Identification of unique ROH regions with unfavorable effects on production and fertility traits in Canadian Holsteins. Genet Sel Evol 2021; 53:68. [PMID: 34461820 PMCID: PMC8406729 DOI: 10.1186/s12711-021-00660-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 08/19/2021] [Indexed: 12/02/2022] Open
Abstract
Background The advent of genomic information and the reduction in the cost of genotyping have led to the use of genomic information to estimate genomic inbreeding as an alternative to pedigree inbreeding. Using genomic measures, effects of genomic inbreeding on production and fertility traits have been observed. However, there have been limited studies on the specific genomic regions causing the observed negative association with the trait of interest. Our aim was to identify unique run of homozygosity (ROH) genotypes present within a given genomic window that display negative associations with production and fertility traits and to quantify the effects of these identified ROH genotypes. Methods In total, 50,575 genotypes based on a 50K single nucleotide polymorphism (SNP) array and 259,871 pedigree records were available. Of these 50,575 genotypes, 46,430 cows with phenotypic records for production and fertility traits and having a first calving date between 2008 and 2018 were available. Unique ROH genotypes identified using a sliding-window approach were fitted into an animal mixed model as fixed effects to determine their effect on production and fertility traits. Results In total, 133 and 34 unique ROH genotypes with unfavorable effects were identified for production and fertility traits, respectively, at a 1% genome-wise false discovery rate. Most of these ROH regions were located on bovine chromosomes 8, 13, 14 and 19 for both production and fertility traits. For production traits, the average of all the unfavorably identified unique ROH genotypes effects were estimated to decrease milk yield by 247.30 kg, fat yield by 11.46 kg and protein yield by 8.11 kg. Similarly, for fertility traits, an average 4.81-day extension in first service to conception, a 0.16 increase in number of services, and a − 0.07 incidence in 56-day non-return rate were observed. Furthermore, a ROH region located on bovine chromosome 19 was identified that, when homozygous, had a negative effect on production traits. Signatures of selection proximate to this region have implicated GH1 as a potential candidate gene, which encodes the growth hormone that binds the growth hormone receptor. This observed negative effect could be a consequence of unfavorable alleles in linkage disequilibrium with favorable alleles. Conclusions ROH genotypes with unfavorable effects on production and fertility traits were identified within and across multiple traits on most chromosomes. These identified ROH genotypes could be included in mate selection programs to minimize their frequency in future generations. Supplementary Information The online version contains supplementary material available at 10.1186/s12711-021-00660-z.
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Affiliation(s)
- Bayode O Makanjuola
- Centre for Genomic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, N1G 2W1, Canada.
| | - Christian Maltecca
- Centre for Genomic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, N1G 2W1, Canada.,Department of Animal Science and Genetics Program, North Carolina State University, Raleigh, NC, 27607, USA
| | - Filippo Miglior
- Centre for Genomic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | | | - Emhimad A Abdalla
- Centre for Genomic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Flavio S Schenkel
- Centre for Genomic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Christine F Baes
- Centre for Genomic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, N1G 2W1, Canada.,Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001, Bern, Switzerland
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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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Makanjuola BO, Maltecca C, Miglior F, Schenkel FS, Baes CF. Effect of recent and ancient inbreeding on production and fertility traits in Canadian Holsteins. BMC Genomics 2020; 21:605. [PMID: 32873253 PMCID: PMC7466804 DOI: 10.1186/s12864-020-07031-w] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 08/27/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Phenotypic performances of livestock animals decline with increasing levels of inbreeding, however, the noticeable decline known as inbreeding depression, may not be due only to the total level of inbreeding, but rather could be distinctly associated with more recent or more ancient inbreeding. Therefore, splitting inbreeding into different age classes could help in assessing detrimental effects of different ages of inbreeding. Hence, this study sought to investigate the effect of recent and ancient inbreeding on production and fertility traits in Canadian Holstein cattle with both pedigree and genomic records. Furthermore, inbreeding coefficients were estimated using traditional pedigree measure (FPED) and genomic measures using segment based (FROH) and marker-by-marker (FGRM) based approaches. RESULTS Inbreeding depression was found for all production and most fertility traits, for example, every 1% increase in FPED, FROH and FGRM was observed to cause a - 44.71, - 40.48 and - 48.72 kg reduction in 305-day milk yield (MY), respectively. Similarly, an extension in first service to conception (FSTC) of 0.29, 0.24 and 0.31 day in heifers was found for every 1% increase in FPED, FROH and FGRM, respectively. Fertility traits that did not show significant depression were observed to move in an unfavorable direction over time. Splitting both pedigree and genomic inbreeding into age classes resulted in recent age classes showing more detrimental inbreeding effects, while more distant age classes caused more favorable effects. For example, a - 1.56 kg loss in 305-day protein yield (PY) was observed for every 1% increase in the most recent pedigree age class, whereas a 1.33 kg gain was found per 1% increase in the most distant pedigree age class. CONCLUSIONS Inbreeding depression was observed for production and fertility traits. In general, recent inbreeding had unfavorable effects, while ancestral inbreeding had favorable effects. Given that more negative effects were estimated from recent inbreeding when compared to ancient inbreeding suggests that recent inbreeding should be the primary focus of selection programs. Also, further work to identify specific recent homozygous regions negatively associated with phenotypic traits could be investigated.
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Affiliation(s)
- Bayode O Makanjuola
- Centre for Genomic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, N1G 2W1, Canada.
| | - Christian Maltecca
- Centre for Genomic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, N1G 2W1, Canada.,Department of Animal Science and Genetics Program, North Carolina State University, Raleigh, NC, 27607, USA
| | - Filippo Miglior
- Centre for Genomic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Flavio S Schenkel
- Centre for Genomic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Christine F Baes
- Centre for Genomic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, N1G 2W1, Canada.,Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001, Bern, Switzerland
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Amaya A, Martínez R, Cerón-Muñoz M. Population structure and genetic diversity in Colombian Simmental cattle. Trop Anim Health Prod 2019; 52:1133-1139. [PMID: 31745753 DOI: 10.1007/s11250-019-02111-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 10/03/2019] [Indexed: 10/25/2022]
Abstract
A vital requirement to design and implement a breeding program is to know the structure and genetic diversity of a population. The aim of this study was to characterize population structure and genetic diversity of the Colombian Simmental cattle. The pedigree file included 27,985 animals born from 1975 to 2017. The level of genetic diversity and breed structure was evaluated through probabilities of gene origin expressed via effective number of founders, ancestors and founders genomes. The inbreeding rates and the degree of genetic connectivity were estimated using a regression analysis and a genetic drift variance analysis, respectively. The lowest effective number of founders and ancestors were 50 and 38 by year, respectively. The average inbreeding by year of birth decreased from 5.06% in 1980 to 2.25% in 2017. The dairy line genetic contributions in the overall population increased significantly in the last 37 years, and the beef line contribution decreased. Regarding the genetic connectivity, Colombian regions (administrative divisions) with the largest cattle population had higher values. The results indicate that the availability of European and North American bulls contributes to genetic diversity by increasing the effective number of founders over time in the Colombian Simmental cattle population. However, the intensive use of relatively few founders causes an unbalanced genetic contribution and the loss of genetic diversity by gene pool erosion.
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Affiliation(s)
- Alejandro Amaya
- Grupo de Investigación GaMMA, Facultad de Ciencias Agrarias, Universidad de Antioquia, Medellín, Colombia.,Grupo de Investigación Ciencia Animal, Facultad de Ciencias Agropecuarias, Universidad de Ciencias Aplicadas y Ambientales U.D.C.A., Bogota, Colombia
| | - Rodrigo Martínez
- Grupo de Investigación en Recursos Genéticos y Biotecnología Animal, Corporación Colombiana de Investigación Agropecuaria (AGROSAVIA), Centro de Investigación Tibaitatá - km 11 vía Mosquera -, Bogotá, Cundinamarca, Colombia
| | - Mario Cerón-Muñoz
- Grupo de Investigación GaMMA, Facultad de Ciencias Agrarias, Universidad de Antioquia, Medellín, Colombia.
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Doekes HP, Veerkamp RF, Bijma P, de Jong G, Hiemstra SJ, Windig JJ. Inbreeding depression due to recent and ancient inbreeding in Dutch Holstein-Friesian dairy cattle. Genet Sel Evol 2019; 51:54. [PMID: 31558150 PMCID: PMC6764141 DOI: 10.1186/s12711-019-0497-z] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 09/19/2019] [Indexed: 02/01/2023] Open
Abstract
Background Inbreeding decreases animal performance (inbreeding depression), but not all inbreeding is expected to be equally harmful. Recent inbreeding is expected to be more harmful than ancient inbreeding, because selection decreases the frequency of deleterious alleles over time. Selection efficiency is increased by inbreeding, a process called purging. Our objective was to investigate effects of recent and ancient inbreeding on yield, fertility and udder health traits in Dutch Holstein–Friesian cows. Methods In total, 38,792 first-parity cows were included. Pedigree inbreeding (\documentclass[12pt]{minimal}
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\begin{document}$$F_{PED}$$\end{document}FPED) was computed and 75 k genotype data were used to compute genomic inbreeding, among others based on regions of homozygosity (ROH) in the genome (\documentclass[12pt]{minimal}
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\begin{document}$$F_{ROH}$$\end{document}FROH). Results Inbreeding depression was observed, e.g. a 1% increase in \documentclass[12pt]{minimal}
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\begin{document}$$F_{ROH}$$\end{document}FROH was associated with a 36.3 kg (SE = 2.4) decrease in 305-day milk yield, a 0.48 day (SE = 0.15) increase in calving interval and a 0.86 unit (SE = 0.28) increase in somatic cell score for day 150 through to 400. These effects equalled − 0.45, 0.12 and 0.05% of the trait means, respectively. When \documentclass[12pt]{minimal}
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\begin{document}$$F_{PED}$$\end{document}FPED was split into generation-based components, inbreeding on recent generations was more harmful than inbreeding on more distant generations for yield traits. When \documentclass[12pt]{minimal}
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\begin{document}$$F_{PED}$$\end{document}FPED was split into new and ancestral components, based on whether alleles were identical-by-descent for the first time or not, new inbreeding was more harmful than ancestral inbreeding, especially for yield traits. For example, a 1% increase in new inbreeding was associated with a 2.42 kg (SE = 0.41) decrease in 305-day fat yield, compared to a 0.03 kg (SE = 0.71) increase for ancestral inbreeding. There were no clear differences between effects of long ROH (recent inbreeding) and short ROH (ancient inbreeding). Conclusions Inbreeding depression was observed for yield, fertility and udder health traits. For yield traits and based on pedigree, inbreeding on recent generations was more harmful than inbreeding on distant generations and there was evidence of purging. Across all traits, long and short ROH contributed to inbreeding depression. In future work, inbreeding depression and purging should be assessed in more detail at the genomic level, using higher density information and genomic time series.
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Affiliation(s)
- Harmen P Doekes
- Wageningen University & Research, Animal Breeding and Genomics, P.O. Box 338, 6700 AH, Wageningen, The Netherlands. .,Wageningen University & Research, Centre for Genetic Resources the Netherlands, P.O. Box 16, 6700 AA, Wageningen, The Netherlands.
| | - Roel F Veerkamp
- Wageningen University & Research, Animal Breeding and Genomics, P.O. Box 338, 6700 AH, Wageningen, The Netherlands
| | - Piter Bijma
- Wageningen University & Research, Animal Breeding and Genomics, P.O. Box 338, 6700 AH, Wageningen, The Netherlands
| | - Gerben de Jong
- Cooperation CRV, Wassenaarweg 20, 6843 NW, Arnhem, The Netherlands
| | - Sipke J Hiemstra
- Wageningen University & Research, Centre for Genetic Resources the Netherlands, P.O. Box 16, 6700 AA, Wageningen, The Netherlands
| | - Jack J Windig
- Wageningen University & Research, Animal Breeding and Genomics, P.O. Box 338, 6700 AH, Wageningen, The Netherlands.,Wageningen University & Research, Centre for Genetic Resources the Netherlands, P.O. Box 16, 6700 AA, Wageningen, The Netherlands
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Sumreddee P, Toghiani S, Hay EH, Roberts A, Agrrey SE, Rekaya R. Inbreeding depression in line 1 Hereford cattle population using pedigree and genomic information. J Anim Sci 2019; 97:1-18. [PMID: 30304409 DOI: 10.1093/jas/sky385] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 10/04/2018] [Indexed: 11/14/2022] Open
Abstract
This study aimed at assessing inbreeding and its effect on growth and fertility traits using the longtime closed line 1 Hereford cattle population. Inbreeding was estimated based on pedigree (FPED) and genomic information. For the latter, three estimates were derived based on the diagonal elements of the genomic relationship matrix using estimated (FGRM) or fixed (FGRM0.5) minor allele frequencies or runs of homozygosity (ROH) (FROH). A pedigree containing 10,186 animals was used to calculate FPED. Genomic inbreeding was evaluated using 785 animals genotyped for 30,810 SNP. Traits analyzed were birth weight (BWT), weaning weight (WWT), yearling weight (YWT), ADG, and age at first calving (AFC). The number of ROH per animal ranged between 6 and 119 segments with an average of 83. The shortest and longest segments were 1.36 and 64.86 Mb long, respectively, reflecting both ancient and recent inbreeding occurring in the last 30 to 40 generations. The average inbreeding was 29.2%, 16.1%, 30.2%, and 22.9% for FPED, FGRM, FGRM0.5, and FROH, respectively. FROH provided the highest correlations with FPED (r = 0.66). Across paternal half-sib families, with minimal variation in FPED, there were substantial variations in their genomic inbreeding. Inbreeding depression analyses showed that a 1% increase in an animal's FPED resulted in a decrease of 1.20 kg, 2.03 kg, and 0.004 kg/d in WWT, YWT, and ADG, respectively. Maternal inbreeding showed significantly negative effects on progeny growth performance. AFC increased by 1.4 and 0.8 d for each 1% increase in FPED of the cow and her dam, respectively. Using genomic inbreeding, similar impact on growth traits was observed although the magnitude of the effect varied between methods. Across all genomic measures, WWT, YWT, and ADG decreased by 0.21 to 0.53 kg, 0.46 to 1.13 kg, and 0.002 to 0.006 kg/d for each 1% increase in genomic inbreeding, respectively. Four chromosomes (9, 12, 17, and 27) were identified to have a significant association between their homozygosity (FROH-CHR) and growth traits. Variability in genomic inbreeding could be useful when deciding between full and half-sib selection candidates. Despite the high level of inbreeding in this study, its negative impact on growth performance was not as severe as expected, which may be attributed to the purging of the deleterious alleles due to natural or artificial selection over time.
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Affiliation(s)
| | - Sajjad Toghiani
- Department of Animal and Dairy Science, The University of Georgia, Athens, GA
| | - El Hamidi Hay
- USDA Agricultural Research Service, Fort Keogh Livestock and Range Research Laboratory, Miles City, MT
| | - Andrew Roberts
- USDA Agricultural Research Service, Fort Keogh Livestock and Range Research Laboratory, Miles City, MT
| | - Samuel E Agrrey
- Department of Poultry Science, The University of Georgia, Athens, GA.,Institute of Bioinformatics, The University of Georgia, Athens, GA
| | - Romdhane Rekaya
- Department of Animal and Dairy Science, The University of Georgia, Athens, GA.,Institute of Bioinformatics, The University of Georgia, Athens, GA.,Department of Statistics, The University of Georgia, Athens, GA
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Howard JT, Tiezzi F, Huang Y, Gray KA, Maltecca C. A heuristic method to identify runs of homozygosity associated with reduced performance in livestock. J Anim Sci 2018; 95:4318-4332. [PMID: 29108032 DOI: 10.2527/jas2017.1664] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Although, for the most part, genome-wide metrics are currently used in managing livestock inbreeding, genomic data offer, in principle, the ability to identify functional inbreeding. Here, we present a heuristic method to identify haplotypes contained within a run of homozygosity (ROH) associated with reduced performance. Results are presented for simulated and swine data. The algorithm comprises 3 steps. Step 1 scans the genome based on marker windows of decreasing size and identifies ROH genotypes associated with an unfavorable phenotype. Within this stage, multiple aggregation steps reduce the haplotype to the smallest possible length. In step 2, the resulting regions are formally tested for significance with the use of a linear mixed model. Lastly, step 3 removes nested windows. The effect of the unfavorable haplotypes identified and their associated haplotype probabilities for a progeny of a given mating pair or an individual can be used to generate an inbreeding load matrix (ILM). Diagonals of ILM characterize the functional individual inbreeding load (IIL). We estimated the accuracy of predicting the phenotype based on IIL. We further compared the significance of the regression coefficient for IIL on phenotypes with genome-wide inbreeding metrics. We tested the algorithm using simulated scenarios (12 scenarios), combining different levels of linkage disequilibrium (LD) and number of loci impacting a quantitative trait. Additionally, we investigated 9 traits from 2 maternal purebred swine lines. In simulated data, as the LD in the population increased, the algorithm identified a greater proportion of the true unfavorable ROH effects. For example, the proportion of highly unfavorable true ROH effects identified rose from 32 to 41% for the low- to the high-LD scenario. In both simulated and real data, the haplotypes identified were contained within a much larger ROH (9.12-12.1 Mb). The IIL prediction accuracy was greater than 0 across all scenarios for simulated data (mean of 0.49 [95% confidence interval 0.47-0.52] for the high-LD scenario) and for nearly all swine traits (mean of 0.17 [SD 0.10]). On average, across simulated and swine data sets, the IIL regression coefficient was more closely related to progeny performance than any genome-wide inbreeding metric. A heuristic method was developed that identified ROH genotypes with reduced performance and characterized the combined effects of ROH genotypes within and across individuals.
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10
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Varona L, Legarra A, Toro MA, Vitezica ZG. Non-additive Effects in Genomic Selection. Front Genet 2018; 9:78. [PMID: 29559995 PMCID: PMC5845743 DOI: 10.3389/fgene.2018.00078] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 02/19/2018] [Indexed: 12/02/2022] Open
Abstract
In the last decade, genomic selection has become a standard in the genetic evaluation of livestock populations. However, most procedures for the implementation of genomic selection only consider the additive effects associated with SNP (Single Nucleotide Polymorphism) markers used to calculate the prediction of the breeding values of candidates for selection. Nevertheless, the availability of estimates of non-additive effects is of interest because: (i) they contribute to an increase in the accuracy of the prediction of breeding values and the genetic response; (ii) they allow the definition of mate allocation procedures between candidates for selection; and (iii) they can be used to enhance non-additive genetic variation through the definition of appropriate crossbreeding or purebred breeding schemes. This study presents a review of methods for the incorporation of non-additive genetic effects into genomic selection procedures and their potential applications in the prediction of future performance, mate allocation, crossbreeding, and purebred selection. The work concludes with a brief outline of some ideas for future lines of that may help the standard inclusion of non-additive effects in genomic selection.
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Affiliation(s)
- Luis Varona
- Departamento de Anatomía, Embriología y Genética Animal, Universidad de Zaragoza, Zaragoza, Spain.,Instituto Agroalimentario de Aragón (IA2), Zaragoza, Spain
| | - Andres Legarra
- Génétique Physiologie et Systèmes d'Elevage (GenPhySE), Institut National de la Recherche Agronomique de Toulouse, Castanet-Tolosan, France
| | - Miguel A Toro
- Departamento Producción Agraria, ETS Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, Madrid, Spain
| | - Zulma G Vitezica
- Génétique Physiologie et Systèmes d'Elevage (GenPhySE), Université de Toulouse, Castanet-Tolosan, France
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Luikart G, Kardos M, Hand BK, Rajora OP, Aitken SN, Hohenlohe PA. Population Genomics: Advancing Understanding of Nature. POPULATION GENOMICS 2018. [DOI: 10.1007/13836_2018_60] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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12
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Reverter A, Porto-Neto LR, Fortes MRS, Kasarapu P, de Cara MAR, Burrow HM, Lehnert SA. Genomic inbreeding depression for climatic adaptation of tropical beef cattle1. J Anim Sci 2017. [DOI: 10.2527/jas.2017.1643] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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13
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Howard JT, Pryce JE, Baes C, Maltecca C. Invited review: Inbreeding in the genomics era: Inbreeding, inbreeding depression, and management of genomic variability. J Dairy Sci 2017; 100:6009-6024. [DOI: 10.3168/jds.2017-12787] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 04/25/2017] [Indexed: 11/19/2022]
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14
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Ferenčaković M, Sölkner J, Kapš M, Curik I. Genome-wide mapping and estimation of inbreeding depression of semen quality traits in a cattle population. J Dairy Sci 2017; 100:4721-4730. [PMID: 28434751 DOI: 10.3168/jds.2016-12164] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 02/27/2017] [Indexed: 11/19/2022]
Abstract
Inbreeding depression is known to affect quantitative traits such as male fertility and sperm quality, but the genetic basis for these associations is poorly understood. Most studies have been limited to examining how pedigree- or marker-derived genome-wide autozygosity is associated with quantitative phenotypes. In this study, we analyzed possible associations of genetic features of inbreeding depression with percentage of live spermatozoa and total number of spermatozoa in 19,720 ejaculates obtained from 554 Austrian Fleckvieh bulls during routine artificial insemination programs. Genome-wide inbreeding depression was estimated and genomic regions contributing to inbreeding depression were mapped. Inbreeding depression did affect total number of spermatozoa, and such depression was predicted by pedigree-based inbreeding levels and genome-wide inbreeding levels based on runs of homozygosity (ROH). Genome-wide inbreeding depression did not seem to affect percentage of live spermatozoa. A model incorporating genetic effects of the bull, environmental factors, and additive genetic and ROH status effects of individual single-nucleotide polymorphisms revealed genomic regions significantly associated with ROH status for total number of spermatozoa (4 regions) or percentage of live spermatozoa (5 regions). All but one region contains genes related to spermatogenesis and sperm morphology. These genomic regions contain genes affecting sperm morphogenesis and efficacy. The results highlight that next-generation sequencing may help explain some of the genetic factors contributing to inbreeding depression of sperm quality traits in Fleckvieh bulls.
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Affiliation(s)
- Maja Ferenčaković
- Department of Animal Science, Faculty of Agriculture, University of Zagreb, Svetosimunska 25, 10000 Zagreb, Croatia
| | - Johann Sölkner
- University of Natural Resources and Life Sciences Vienna, Department of Sustainable Agricultural Systems, Division of Livestock Sciences, Gregor Mendel Str. 33, A-1180 Vienna, Austria.
| | - Miroslav Kapš
- Department of Animal Science, Faculty of Agriculture, University of Zagreb, Svetosimunska 25, 10000 Zagreb, Croatia
| | - Ino Curik
- Department of Animal Science, Faculty of Agriculture, University of Zagreb, Svetosimunska 25, 10000 Zagreb, Croatia
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Effects of abiotic factors on ecosystem health of Taihu Lake, China based on eco-exergy theory. Sci Rep 2017; 7:42872. [PMID: 28220835 PMCID: PMC5318890 DOI: 10.1038/srep42872] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 01/17/2017] [Indexed: 11/28/2022] Open
Abstract
A lake ecosystem is continuously exposed to environmental stressors with non-linear interrelationships between abiotic factors and aquatic organisms. Ecosystem health depicts the capacity of system to respond to external perturbations and still maintain structure and function. In this study, we explored the effects of abiotic factors on ecosystem health of Taihu Lake in 2013, China from a system-level perspective. Spatiotemporal heterogeneities of eco-exergy and specific eco-exergy served as thermodynamic indicators to represent ecosystem health in the lake. The results showed the plankton community appeared more energetic in May, and relatively healthy in Gonghu Bay with both higher eco-exergy and specific eco-exergy; a eutrophic state was likely discovered in Zhushan Bay with higher eco-exergy but lower specific eco-exergy. Gradient Boosting Machine (GBM) approach was used to explain the non-linear relationships between two indicators and abiotic factors. This analysis revealed water temperature, inorganic nutrients, and total suspended solids greatly contributed to the two indicators that increased. However, pH rise driven by inorganic carbon played an important role in undermining ecosystem health, particularly when pH was higher than 8.2. This implies that climate change with rising CO2 concentrations has the potential to aggravate eutrophication in Taihu Lake where high nutrient loads are maintained.
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Kardos M, Taylor HR, Ellegren H, Luikart G, Allendorf FW. Genomics advances the study of inbreeding depression in the wild. Evol Appl 2016; 9:1205-1218. [PMID: 27877200 PMCID: PMC5108213 DOI: 10.1111/eva.12414] [Citation(s) in RCA: 143] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 08/05/2016] [Indexed: 12/12/2022] Open
Abstract
Inbreeding depression (reduced fitness of individuals with related parents) has long been a major focus of ecology, evolution, and conservation biology. Despite decades of research, we still have a limited understanding of the strength, underlying genetic mechanisms, and demographic consequences of inbreeding depression in the wild. Studying inbreeding depression in natural populations has been hampered by the inability to precisely measure individual inbreeding. Fortunately, the rapidly increasing availability of high-throughput sequencing data means it is now feasible to measure the inbreeding of any individual with high precision. Here, we review how genomic data are advancing our understanding of inbreeding depression in the wild. Recent results show that individual inbreeding and inbreeding depression can be measured more precisely with genomic data than via traditional pedigree analysis. Additionally, the availability of genomic data has made it possible to pinpoint loci with large effects contributing to inbreeding depression in wild populations, although this will continue to be a challenging task in many study systems due to low statistical power. Now that reliably measuring individual inbreeding is no longer a limitation, a major focus of future studies should be to more accurately quantify effects of inbreeding depression on population growth and viability.
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Affiliation(s)
- Marty Kardos
- Department of Evolutionary BiologyEvolutionary Biology CentreUppsala UniversityUppsalaSweden
| | | | - Hans Ellegren
- Department of Evolutionary BiologyEvolutionary Biology CentreUppsala UniversityUppsalaSweden
| | - Gordon Luikart
- Division of Biological SciencesUniversity of MontanaMissoulaMTUSA
- Flathead Lake Biological StationDivision of Biological SciencesUniversity of MontanaPolsonMTUSA
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Howard JT, Tiezzi F, Huang Y, Gray KA, Maltecca C. Characterization and management of long runs of homozygosity in parental nucleus lines and their associated crossbred progeny. Genet Sel Evol 2016; 48:91. [PMID: 27884108 PMCID: PMC5123398 DOI: 10.1186/s12711-016-0269-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 11/10/2016] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND In nucleus populations, regions of the genome that have a high frequency of runs of homozygosity (ROH) occur and are associated with a reduction in genetic diversity, as well as adverse effects on fitness. It is currently unclear whether, and to what extent, ROH stretches persist in the crossbred genome and how genomic management in the nucleus population might impact low diversity regions and its implications on the crossbred genome. METHODS We calculated a ROH statistic based on lengths of 5 (ROH5) or 10 (ROH10) Mb across the genome for genotyped Landrace (LA), Large White (LW) and Duroc (DU) dams. We simulated crossbred dam (LA × LW) and market [DU × (LA × LW)] animal genotypes based on observed parental genotypes and the ROH frequency was tabulated. We conducted a simulation using observed genotypes to determine the impact of minimizing parental relationships on multiple diversity metrics within nucleus herds, i.e. pedigree-(A), SNP-by-SNP relationship matrix or ROH relationship matrix. Genome-wide metrics included, pedigree inbreeding, heterozygosity and proportion of the genome in ROH of at least 5 Mb. Lastly, the genome was split into bins of increasing ROH5 frequency and, within each bin, heterozygosity, ROH5 and length (Mb) of ROH were evaluated. RESULTS We detected regions showing high frequencies of either ROH5 and/or ROH10 across both LW and LA on SSC1, SSC4, and SSC14, and across all breeds on SSC9. Long haplotypes were shared across parental breeds and thus, regions of ROH persisted in crossbred animals. Averaged across replicates and breeds, progeny had higher levels of heterozygosity (0.0056 ± 0.002%) and lower proportion of the genome in a ROH of at least 5 Mb (-0.015 ± 0.003%) than their parental genomes when genomic relationships were constrained, while pedigree relationships resulted in negligible differences at the genomic level. Across all breeds, only genomic data was able to target low diversity regions. CONCLUSIONS We show that long stretches of ROH present in the parents persist in crossbred animals. Furthermore, compared to using pedigree relationships, using genomic information to constrain parental relationships resulted in maintaining more genetic diversity and more effectively targeted low diversity regions.
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Affiliation(s)
- Jeremy T Howard
- Department of Animal Science, North Carolina State University, Raleigh, NC, 27695-7627, USA.
| | - Francesco Tiezzi
- Department of Animal Science, North Carolina State University, Raleigh, NC, 27695-7627, USA
| | - Yijian Huang
- Smithfield Premium Genetics, Rose Hill, NC, 28458, USA
| | - Kent A Gray
- Smithfield Premium Genetics, Rose Hill, NC, 28458, USA
| | - Christian Maltecca
- Department of Animal Science, North Carolina State University, Raleigh, NC, 27695-7627, USA.,Genetics Program, North Carolina State University, Raleigh, NC, 27695-7627, USA
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