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Blondeau Da Silva S, Mwacharo JM, Li M, Ahbara A, Muchadeyi FC, Dzomba EF, Lenstra JA, Da Silva A. IBD sharing patterns as intra-breed admixture indicators in small ruminants. Heredity (Edinb) 2024; 132:30-42. [PMID: 37919398 PMCID: PMC10799084 DOI: 10.1038/s41437-023-00658-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 10/18/2023] [Accepted: 10/18/2023] [Indexed: 11/04/2023] Open
Abstract
In this study, we investigated how IBD patterns shared between individuals of the same breed could be informative of its admixture level, with the underlying assumption that the most admixed breeds, i.e. the least genetically isolated, should have a much more fragmented genome. We considered 111 goat breeds (i.e. 2501 individuals) and 156 sheep breeds (i.e. 3304 individuals) from Europe, Africa and Asia, for which beadchip SNP genotypes had been performed. We inferred the breed's level of admixture from: (i) the proportion of the genome shared by breed's members (i.e. "genetic integrity level" assessed from ADMIXTURE software analyses), and (ii) the "AV index" (calculated from Reynolds' genetic distances), used as a proxy for the "genetic distinctiveness". In both goat and sheep datasets, the statistical analyses (comparison of means, Spearman correlations, LM and GAM models) revealed that the most genetically isolated breeds, also showed IBD profiles made up of more shared IBD segments, which were also longer. These results pave the way for further research that could lead to the development of admixture indicators, based on the characterization of intra-breed shared IBD segments, particularly effective as they would be independent of the knowledge of the whole genetic landscape in which the breeds evolve. Finally, by highlighting the fragmentation experienced by the genomes subjected to crossbreeding carried out over the last few generations, the study reminds us of the need to preserve local breeds and the integrity of their adaptive architectures that have been shaped over the centuries.
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Affiliation(s)
| | - Joram M Mwacharo
- Animal and Veterinary Sciences, Scotlands Rural College (SRUC) and Centre for Tropical Livestock Genetics and Health (CTLGH), The Roslin Institute Building, EH25 9RG, Midlothian, UK
- Small Ruminant Genomics, International Centre for Agricultural Research in the Dry Areas (ICARDA), P.O. Box 5689, Addis Ababa, Ethiopia
| | - Menghua Li
- College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Abulgasim Ahbara
- Animal and Veterinary Sciences, Scotlands Rural College (SRUC) and Centre for Tropical Livestock Genetics and Health (CTLGH), The Roslin Institute Building, EH25 9RG, Midlothian, UK
- Department of Zoology, Faculty of Sciences, Misurata University, Misurata, Libya
| | | | - Edgar Farai Dzomba
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville, 3209, South Africa
| | - Johannes A Lenstra
- Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - Anne Da Silva
- Faculté des Sciences et Techniques de Limoges, E2LIM, 87000, Limoges, France.
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Friedrich J, Bailey RI, Talenti A, Chaudhry U, Ali Q, Obishakin EF, Ezeasor C, Powell J, Hanotte O, Tijjani A, Marshall K, Prendergast J, Wiener P. Mapping restricted introgression across the genomes of admixed indigenous African cattle breeds. Genet Sel Evol 2023; 55:91. [PMID: 38097935 PMCID: PMC10722721 DOI: 10.1186/s12711-023-00861-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 11/24/2023] [Indexed: 12/17/2023] Open
Abstract
BACKGROUND The genomes of indigenous African cattle are composed of components with Middle Eastern (taurine) and South Asian (indicine) origins, providing a valuable model to study hybridization and to identify genetic barriers to gene flow. In this study, we analysed indigenous African cattle breeds as models of hybrid zones, considering taurine and indicine samples as ancestors. In a genomic cline analysis of whole-genome sequence data, we considered over 8 million variants from 144 animals, which allows for fine-mapping of potential genomic incompatibilities at high resolution across the genome. RESULTS We identified several thousand variants that had significantly steep clines ('SCV') across the whole genome, indicating restricted introgression. Some of the SCV were clustered into extended regions, with the longest on chromosome 7, spanning 725 kb and including 27 genes. We found that variants with a high phenotypic impact (e.g. indels, intra-genic and missense variants) likely represent greater genetic barriers to gene flow. Furthermore, our findings provide evidence that a large proportion of breed differentiation in African cattle could be linked to genomic incompatibilities and reproductive isolation. Functional evaluation of genes with SCV suggest that mitonuclear incompatibilities and genes associated with fitness (e.g. resistance to paratuberculosis) could account for restricted gene flow in indigenous African cattle. CONCLUSIONS To our knowledge, this is the first time genomic cline analysis has been applied to identify restricted introgression in the genomes of indigenous African cattle and the results provide extended insights into mechanisms (e.g. genomic incompatibilities) contributing to hybrid differentiation. These results have important implications for our understanding of genetic incompatibilities and reproductive isolation and provide important insights into the impact of cross-breeding cattle with the aim of producing offspring that are both hardy and productive.
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Affiliation(s)
- Juliane Friedrich
- Division of Genetics and Genomics, The Roslin Institute and Royal (Dick), School of Veterinary Studies, University of Edinburgh, Midlothian, UK.
| | - Richard I Bailey
- Department of Ecology and Vertebrate Zoology, University of Łódź, Łódź, Poland
| | - Andrea Talenti
- Division of Genetics and Genomics, The Roslin Institute and Royal (Dick), School of Veterinary Studies, University of Edinburgh, Midlothian, UK
| | - Umer Chaudhry
- School of Veterinary Medicine, St. George's University, St. George's, Caribbean, Grenada
| | - Qasim Ali
- Department of Parasitology, The University of Agriculture Dera Ismail Khan, Khyber Pakhtunkhwa, Pakistan
| | - Emmanuel F Obishakin
- Biotechnology Division, National Veterinary Research Institute, Vom, Plateau State, Nigeria
| | - Chukwunonso Ezeasor
- Department of Veterinary Pathology and Microbiology, University of Nigeria, Nsukka, Enugu State, Nigeria
| | - Jessica Powell
- Division of Infection and Immunity, The Roslin Institute and Royal (Dick), School of Veterinary Studies, University of Edinburgh, Midlothian, UK
| | - Olivier Hanotte
- International Livestock Research Institute (ILRI), Addis Ababa, Ethiopia
- School of Life Sciences, University of Nottingham, Nottingham, UK
- Centre for Tropical Livestock Genetics and Health (CTLGH), The Roslin Institute, University of Edinburgh, Midlothian, UK
| | | | - Karen Marshall
- Centre for Tropical Livestock Genetics and Health (CTLGH), ILRI Kenya, Nairobi, Kenya
| | - James Prendergast
- Division of Genetics and Genomics, The Roslin Institute and Royal (Dick), School of Veterinary Studies, University of Edinburgh, Midlothian, UK
| | - Pamela Wiener
- Division of Genetics and Genomics, The Roslin Institute and Royal (Dick), School of Veterinary Studies, University of Edinburgh, Midlothian, UK.
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Velayudhan SM, Yin T, Alam S, Brügemann K, Sejian V, Bhatta R, Schlecht E, König S. Unraveling the Genomic Association for Milk Production Traits and Signatures of Selection of Cattle in a Harsh Tropical Environment. BIOLOGY 2023; 12:1483. [PMID: 38132309 PMCID: PMC10740459 DOI: 10.3390/biology12121483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 11/15/2023] [Accepted: 11/29/2023] [Indexed: 12/23/2023]
Abstract
A study was designed to identify the genomic regions associated with milk production traits in a dairy cattle population reared by smallholder farmers in the harsh and challenging tropical savanna climate of Bengaluru, India. This study is a first-of-its-kind attempt to identify the selection sweeps for the dairy cattle breeds reared in such an environment. Two hundred forty lactating dairy cows reared by 68 farmers across the rural-urban transiting regions of Bengaluru were selected for this study. A genome-wide association study (GWAS) was performed to identify candidate genes for test-day milk yield, solids-not-fat (SNF), milk lactose, milk density and clinical mastitis. Furthermore, the cross-population extended haplotype homozygosity (XP-EHH) methodology was adopted to scan the dairy cattle breeds (Holstein Friesian, Jersey and Crossbred) in Bengaluru. Two SNPs, rs109340659 and rs41571523, were observed to be significantly associated with test-day milk yield. No significant SNPs were observed for the remaining production traits. The GWAS for milk lactose revealed one SNP (rs41634101) that was very close to the threshold limit, though not significant. The potential candidate genes fibrosin-like 1 (FBRSL) and calcium voltage-gated channel auxiliary subunit gamma 3 (CACN) were identified to be in close proximity to the SNP identified for test-day milk yield. These genes were observed to be associated with milk production traits based on previous reports. Furthermore, the selection signature analysis revealed a number of regions under selection for the breed-group comparisons (Crossbred-HF, Crossbred-J and HF-J). Functional analysis of these annotated genes under selection indicated pathways and mechanisms involving ubiquitination, cell signaling and immune response. These findings point towards the probable selection of dairy cows in Bengaluru for thermotolerance.
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Affiliation(s)
| | - Tong Yin
- Institute of Animal Breeding and Genetics, Justus-Liebig-University Gießen, Ludwigstraße 21 b, 35390 Gießen, Germany; (S.M.V.); (T.Y.)
| | - Shahin Alam
- Animal Husbandry in the Tropics and Subtropics, University of Kassel and Georg-August-Universität Göttingen, Steinstr. 19, 37213 Witzenhausen, Germany; (S.A.)
| | - Kerstin Brügemann
- Institute of Animal Breeding and Genetics, Justus-Liebig-University Gießen, Ludwigstraße 21 b, 35390 Gießen, Germany; (S.M.V.); (T.Y.)
| | - Veerasamy Sejian
- National Institute of Animal Nutrition and Physiology (NIANP), Hosur Rd, Chennakeshava Nagar, Adugodi, Bengaluru 560030, India
| | - Raghavendra Bhatta
- National Institute of Animal Nutrition and Physiology (NIANP), Hosur Rd, Chennakeshava Nagar, Adugodi, Bengaluru 560030, India
| | - Eva Schlecht
- Animal Husbandry in the Tropics and Subtropics, University of Kassel and Georg-August-Universität Göttingen, Steinstr. 19, 37213 Witzenhausen, Germany; (S.A.)
| | - Sven König
- Institute of Animal Breeding and Genetics, Justus-Liebig-University Gießen, Ludwigstraße 21 b, 35390 Gießen, Germany; (S.M.V.); (T.Y.)
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Kambal S, Tijjani A, Ibrahim SAE, Ahmed MKA, Mwacharo JM, Hanotte O. Candidate signatures of positive selection for environmental adaptation in indigenous African cattle: A review. Anim Genet 2023; 54:689-708. [PMID: 37697736 DOI: 10.1111/age.13353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 07/28/2023] [Accepted: 08/19/2023] [Indexed: 09/13/2023]
Abstract
Environmental adaptation traits of indigenous African cattle are increasingly being investigated to respond to the need for sustainable livestock production in the context of unpredictable climatic changes. Several studies have highlighted genomic regions under positive selection probably associated with adaptation to environmental challenges (e.g. heat stress, trypanosomiasis, tick and tick-borne diseases). However, little attention has focused on pinpointing the candidate causative variant(s) controlling the traits. This review compiled information from 22 studies on signatures of positive selection in indigenous African cattle breeds to identify regions under positive selection. We highlight some key candidate genome regions and genes of relevance to the challenges of living in extreme environments (high temperature, high altitude, high infectious disease prevalence). They include candidate genes involved in biological pathways relating to innate and adaptive immunity (e.g. BoLAs, SPAG11, IL1RL2 and GFI1B), heat stress (e.g. HSPs, SOD1 and PRLH) and hypoxia responses (e.g. BDNF and INPP4A). Notably, the highest numbers of candidate regions are found on BTA3, BTA5 and BTA7. They overlap with genes playing roles in several biological functions and pathways. These include but are not limited to growth and feed intake, cell stability, protein stability and sweat gland development. This review may further guide targeted genome studies aiming to assess the importance of candidate causative mutations, within regulatory and protein-coding genome regions, to further understand the biological mechanisms underlying African cattle's unique adaption.
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Affiliation(s)
- Sumaya Kambal
- Livestock Genetics, International Livestock Research Institute, Addis Ababa, Ethiopia
- Department of Genetics and Animal Breeding, Faculty of Animal Production, University of Khartoum, Khartoum, Sudan
- Department of Bioinformatics and Biostatistics, National University, Khartoum, Sudan
| | - Abdulfatai Tijjani
- Centre for Tropical Livestock Genetics and Health, International Livestock Research Institute, Addis Ababa, Ethiopia
- The Jackson Laboratory, Bar Harbor, Maine, USA
| | - Sabah A E Ibrahim
- Department of Bioinformatics and Biostatistics, National University, Khartoum, Sudan
| | - Mohamed-Khair A Ahmed
- Department of Genetics and Animal Breeding, Faculty of Animal Production, University of Khartoum, Khartoum, Sudan
| | - Joram M Mwacharo
- Scotland's Rural College and Centre for Tropical Livestock Genetics and Health, Edinburgh, UK
- Small Ruminant Genomics, International Centre for Agricultural Research in the Dry Areas, Addis Ababa, Ethiopia
| | - Olivier Hanotte
- Livestock Genetics, International Livestock Research Institute, Addis Ababa, Ethiopia
- Centre for Tropical Livestock Genetics and Health, International Livestock Research Institute, Addis Ababa, Ethiopia
- School of Life Sciences, University of Nottingham, Nottingham, UK
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5
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Al Kalaldeh M, Swaminathan M, Podtar V, Jadhav S, Dhanikachalam V, Joshi A, Gibson JP. Detection of genomic regions that differentiate Bos indicus from Bos taurus ancestral breeds for milk yield in Indian crossbred cows. Front Genet 2023; 13:1082802. [PMID: 36699459 PMCID: PMC9868639 DOI: 10.3389/fgene.2022.1082802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 12/20/2022] [Indexed: 01/11/2023] Open
Abstract
Introduction: In India, crossbred cows incorporate the high production of B. taurus dairy breeds and the environmental adaptation of local B. indicus cattle. Adaptation to different environments and selection in milk production have shaped the genetic differences between B. indicus and B. taurus cattle. The aim of this paper was to detect, for milk yield of crossbred cows, quantitative trait loci (QTL) that differentiate B. indicus from B. taurus ancestry, as well as QTL that are segregating within the ancestral breeds. Methods: A total of 123,042 test-day milk records for 4,968 crossbred cows, genotyped with real and imputed 770 K SNP, were used. Breed origins were assigned to haplotypes of crossbred cows, and from that, were assigned to SNP alleles. Results: At a false discovery rate (FDR) of 30%, a large number of genomic regions showed significant effects of B. indicus versus B. taurus origin on milk yield, with positive effects coming from both ancestors. No significant regions were detected for Holstein Friesian (HF) versus Jersey effects on milk yield. Additionally, no regions for SNP alleles segregating within indigenous, within HF, and within Jersey were detected. The most significant effects, at FDR 5%, were found in a region on BTA5 (43.98-49.44 Mbp) that differentiates B. indicus from B. taurus, with an estimated difference between homozygotes of approximately 10% of average yield, in favour of B. indicus origin. Discussion: Our results indicate that evolutionary differences between B. indicus and B. taurus cattle for milk yield, as expressed in crossbred cows, occur at many causative loci across the genome. Although subject to the usual first estimation bias, some of the loci appear to have large effects that might make them useful for genomic selection in crossbreds, if confirmed in subsequent studies.
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Affiliation(s)
- Mohammad Al Kalaldeh
- Centre for Genetic Analysis and Applications, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia,*Correspondence: Mohammad Al Kalaldeh, ; John P. Gibson,
| | - Marimuthu Swaminathan
- BAIF Development Research Foundation and Central Research Station, Pune, Maharashtra, India
| | - Vinod Podtar
- BAIF Development Research Foundation and Central Research Station, Pune, Maharashtra, India
| | - Santoshkumar Jadhav
- BAIF Development Research Foundation and Central Research Station, Pune, Maharashtra, India
| | - Velu Dhanikachalam
- BAIF Development Research Foundation and Central Research Station, Pune, Maharashtra, India
| | - Akshay Joshi
- BAIF Development Research Foundation and Central Research Station, Pune, Maharashtra, India
| | - John P. Gibson
- Centre for Genetic Analysis and Applications, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia,*Correspondence: Mohammad Al Kalaldeh, ; John P. Gibson,
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6
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Moradi MH, Mahmodi R, Farahani AHK, Karimi MO. Genome-wide evaluation of copy gain and loss variations in three Afghan sheep breeds. Sci Rep 2022; 12:14286. [PMID: 35996004 PMCID: PMC9395407 DOI: 10.1038/s41598-022-18571-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 08/16/2022] [Indexed: 11/23/2022] Open
Abstract
Copy number variation (CNV) is one of the main sources of variation between different individuals that has recently attracted much researcher interest as a major source for heritable variation in complex traits. The aim of this study was to identify CNVs in Afghan indigenous sheep consisting of three Arab, Baluchi, and Gadik breeds using genomic arrays containing 53,862 single nucleotide polymorphism (SNP) markers. Data were analyzed using the Hidden Markov Model (HMM) of PennCNV software. In this study, out of 45 sheep studied, 97.8% (44 animals) have shown CNVs. In total, 411 CNVs were observed for autosomal chromosomes and the entire sequence length of around 144 Mb was identified across the genome. The average number of CNVs per each sheep was 9.13. The identified CNVs for Arab, Baluchi, and Gadik breeds were 306, 62, and 43, respectively. After merging overlapped regions, a total of 376 copy number variation regions (CNVR) were identified, which are 286, 50, and 40 for Arab, Baluchi, and Gadik breeds, respectively. Bioinformatics analysis was performed to identify the genes and QTLs reported in these regions and the biochemical pathways involved by these genes. The results showed that many of these CNVRs overlapped with the genes or QTLs that are associated with various pathways such as immune system development, growth, reproduction, and environmental adaptions. Furthermore, to determine a genome-wide pattern of selection signatures in Afghan sheep breeds, the unbiased estimates of FST was calculated and the results indicated that 37 of the 376 CNVRs (~ 10%) have been also under selection signature, most of those overlapped with the genes influencing production, reproduction and immune system. Finally, the statistical methods used in this study was applied in an external dataset including 96 individuals of the Iranian sheep breed. The results indicated that 20 of the 114 CNVRs (18%) identified in Iranian sheep breed were also identified in our study, most of those overlapped with the genes influencing production, reproduction and immune system. Overall, this is the first attempts to develop the genomic map of loss and gain variation in the genome of Afghan indigenous sheep breeds, and may be important to shed some light on the genomic regions associated with some economically important traits in these breeds.
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Affiliation(s)
- Mohammad Hossein Moradi
- Department of Animal Science, Faculty of Agriculture and Natural Resources, Arak University, Arak, 38156-8-8349, Iran.
| | - Roqiah Mahmodi
- Department of Animal Science, Faculty of Agriculture and Natural Resources, Arak University, Arak, 38156-8-8349, Iran
| | | | - Mohammad Osman Karimi
- Department of Animal Science, Faculty of Agriculture and Natural Resources, Herat University, Herat, Afghanistan
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7
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Kooverjee BB, Soma P, Van Der Nest MA, Scholtz MM, Neser FWC. Selection Signatures in South African Nguni and Bonsmara Cattle Populations Reveal Genes Relating to Environmental Adaptation. Front Genet 2022; 13:909012. [PMID: 35783284 PMCID: PMC9247466 DOI: 10.3389/fgene.2022.909012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/17/2022] [Indexed: 11/30/2022] Open
Abstract
Climate change is a major influencing factor in beef production. The greenhouse gases produced from livestock production systems contribute to the overall greenhouse gas emissions. The aim of this study was to identify selection signatures within and between Nguni and Bonsmara cattle in relation to production and adaptation. For this purpose, genomic 150 K single nucleotide polymorphism data from Nguni (n = 231) and Bonsmara (n = 252) cattle in South Africa were used. Extended haplotype homozygosity (EHH) based analysis was executed within each population using integrated haplotype score (iHS). The R package rehh was used for detecting selection signatures across the two populations with cross population EHH (XP-EHH). Total of 121 regions of selection signatures were detected (p < 0.0001) in the Bonsmara and Nguni populations. Several genes relating to DNA methylation, heat stress, feed efficiency and nitrogen metabolism were detected within and between each population. These regions also included QTLs associated with residual feed intake, residual gain, carcass weight, stature and body weight in the Bonsmara, while QTLs associated with conception rate, shear force, tenderness score, juiciness, temperament, heat tolerance, feed efficiency and age at puberty were identified in Nguni. Based on the results of the study it is recommended that the Nguni and Bonsmara be utilized in crossbreeding programs as they have beneficial traits that may allow them to perform better in the presence of climate change. Results of this study coincide with Nguni and Bonsmara breed characteristics and performance, and furthermore support informative crossbreeding programs to enhance livestock productivity in South Africa.
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Affiliation(s)
- Bhaveni B. Kooverjee
- Department of Animal Breeding and Genetics, Animal Production, Agricultural Research Council, Pretoria, South Africa
- Department of Animal, Wildlife and Grassland Sciences, University of the Free State, Bloemfontein, South Africa
- *Correspondence: Bhaveni B. Kooverjee, ; Pranisha Soma,
| | - Pranisha Soma
- Department of Animal Breeding and Genetics, Animal Production, Agricultural Research Council, Pretoria, South Africa
- *Correspondence: Bhaveni B. Kooverjee, ; Pranisha Soma,
| | | | - Michiel M. Scholtz
- Department of Animal Breeding and Genetics, Animal Production, Agricultural Research Council, Pretoria, South Africa
- Department of Animal, Wildlife and Grassland Sciences, University of the Free State, Bloemfontein, South Africa
| | - Frederick W. C. Neser
- Department of Animal, Wildlife and Grassland Sciences, University of the Free State, Bloemfontein, South Africa
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8
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Vanvanhossou SFU, Yin T, Scheper C, Fries R, Dossa LH, König S. Unraveling Admixture, Inbreeding, and Recent Selection Signatures in West African Indigenous Cattle Populations in Benin. Front Genet 2021; 12:657282. [PMID: 34956303 PMCID: PMC8694269 DOI: 10.3389/fgene.2021.657282] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 10/07/2021] [Indexed: 11/13/2022] Open
Abstract
The Dwarf Lagune and the Savannah Somba cattle in Benin are typical representatives of the endangered West African indigenous Shorthorn taurine. The Lagune was previously exported to African and European countries and bred as Dahomey cattle, whereas the Somba contributed to the formation of two indigenous hybrids known as Borgou and Pabli cattle. These breeds are affected by demographic, economic, and environmental pressures in local production systems. Considering current and historical genomic data, we applied a formal test of admixture, estimated admixture proportions, and computed genomic inbreeding coefficients to characterize the five breeds. Subsequently, we unraveled the most recent selection signatures using the cross-population extended haplotype homozygosity approach, based on the current and historical genotypes. Results from principal component analyses and high proportion of Lagune ancestry confirm the Lagune origin of the European Dahomey cattle. Moreover, the Dahomey cattle displayed neither indicine nor European taurine (EUT) background, but they shared on average 40% of autozygosity from common ancestors, dated approximately eight generations ago. The Lagune cattle presented inbreeding coefficients larger than 0.13; however, the Somba and the hybrids (Borgou and Pabli) were less inbred (≤0.08). We detected evidence of admixture in the Somba and Lagune cattle, but they exhibited a similar African taurine (AFT) ancestral proportion (≥96%) to historical populations, respectively. A moderate and stable AFT ancestral proportion (62%) was also inferred for less admixed hybrid cattle including the Pabli. In contrast, the current Borgou samples displayed a lower AFT ancestral proportion (47%) than historical samples (63%). Irrespective of the admixture proportions, the hybrid populations displayed more selection signatures related to economic traits (reproduction, growth, and milk) than the taurine. In contrast, the taurine, especially the Somba, presented several regions known to be associated with adaptive traits (immunity and feed efficiency). The identified subregion of bovine leukocyte antigen (BoLA) class IIb (including DSB and BOLA-DYA) in Somba cattle is interestingly uncommon in other African breeds, suggesting further investigations to understand its association with specific adaptation to endemic diseases in Benin. Overall, our study provides deeper insights into recent evolutionary processes in the Beninese indigenous cattle and their aptitude for conservation and genetic improvement.
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Affiliation(s)
| | - Tong Yin
- Institute of Animal Breeding and Genetics, Justus-Liebig-University Gießen, Gießen, Germany
| | - Carsten Scheper
- Institute of Animal Breeding and Genetics, Justus-Liebig-University Gießen, Gießen, Germany
| | - Ruedi Fries
- Chair of Animal Breeding, Technische Universität München, Freising-Weihenstephan, Germany
| | - Luc Hippolyte Dossa
- School of Science and Technics of Animal Production, Faculty of Agricultural Sciences, University of Abomey-Calavi, Abomey-Calavi, Benin
| | - Sven König
- Institute of Animal Breeding and Genetics, Justus-Liebig-University Gießen, Gießen, Germany
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9
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Gebrehiwot NZ, Aliloo H, Strucken EM, Marshall K, Al Kalaldeh M, Missohou A, Gibson JP. Inference of Ancestries and Heterozygosity Proportion and Genotype Imputation in West African Cattle Populations. Front Genet 2021; 12:584355. [PMID: 33841491 PMCID: PMC8025404 DOI: 10.3389/fgene.2021.584355] [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: 07/17/2020] [Accepted: 02/22/2021] [Indexed: 11/24/2022] Open
Abstract
Several studies have evaluated computational methods that infer the haplotypes from population genotype data in European cattle populations. However, little is known about how well they perform in African indigenous and crossbred populations. This study investigates: (1) global and local ancestry inference; (2) heterozygosity proportion estimation; and (3) genotype imputation in West African indigenous and crossbred cattle populations. Principal component analysis (PCA), ADMIXTURE, and LAMP-LD were used to analyse a medium-density single nucleotide polymorphism (SNP) dataset from Senegalese crossbred cattle. Reference SNP data of East and West African indigenous and crossbred cattle populations were used to investigate the accuracy of imputation from low to medium-density and from medium to high-density SNP datasets using Minimac v3. The first two principal components differentiated Bos indicus from European Bos taurus and African Bos taurus from other breeds. Irrespective of assuming two or three ancestral breeds for the Senegalese crossbreds, breed proportion estimates from ADMIXTURE and LAMP-LD showed a high correlation (r ≥ 0.981). The observed ancestral origin heterozygosity proportion in putative F1 crosses was close to the expected value of 1.0, and clearly differentiated F1 from all other crosses. The imputation accuracies (estimated as correlation) between imputed and the real data in crossbred animals ranged from 0.142 to 0.717 when imputing from low to medium-density, and from 0.478 to 0.899 for imputation from medium to high-density. The imputation accuracy was generally higher when the reference data came from the same geographical region as the target population, and when crossbred reference data was used to impute crossbred genotypes. The lowest imputation accuracies were observed for indigenous breed genotypes. This study shows that ancestral origin heterozygosity can be estimated with high accuracy and will be far superior to the use of observed individual heterozygosity for estimating heterosis in African crossbred populations. It was not possible to achieve high imputation accuracy in West African crossbred or indigenous populations based on reference data sets from East Africa, and population-specific genotyping with high-density SNP assays is required to improve imputation.
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Affiliation(s)
- Netsanet Z Gebrehiwot
- Centre for Genetic Analysis and Applications, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
| | - Hassan Aliloo
- Centre for Genetic Analysis and Applications, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
| | - Eva M Strucken
- Centre for Genetic Analysis and Applications, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
| | - Karen Marshall
- International Livestock Research Institute and Centre for Tropical Livestock Genetics and Health, Nairobi, Kenya
| | - Mohammad Al Kalaldeh
- Centre for Genetic Analysis and Applications, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
| | - Ayao Missohou
- L'École Inter-États des Sciences et Médecine Vétérinaires de Dakar (EISMV), Dakar, Senegal
| | - John P Gibson
- Centre for Genetic Analysis and Applications, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
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Gebrehiwot NZ, Strucken EM, Marshall K, Aliloo H, Gibson JP. SNP panels for the estimation of dairy breed proportion and parentage assignment in African crossbred dairy cattle. Genet Sel Evol 2021; 53:21. [PMID: 33653262 PMCID: PMC7923343 DOI: 10.1186/s12711-021-00615-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 02/17/2021] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Understanding the relationship between genetic admixture and phenotypic performance is crucial for the optimization of crossbreeding programs. The use of small sets of informative ancestry markers can be a cost-effective option for the estimation of breed composition and for parentage assignment in situations where pedigree recording is difficult. The objectives of this study were to develop small single nucleotide polymorphism (SNP) panels that can accurately estimate the total dairy proportion and assign parentage in both West and East African crossbred dairy cows. METHODS Medium- and high-density SNP genotype data (Illumina BovineSNP50 and BovineHD Beadchip) for 4231 animals sampled from African crossbreds, African Bos taurus, European Bos taurus, Bos indicus, and African indigenous populations were used. For estimating breed composition, the absolute differences in allele frequency were calculated between pure ancestral breeds to identify SNPs with the highest discriminating power, and different combinations of SNPs weighted by ancestral origin were tested against estimates based on all available SNPs. For parentage assignment, informative SNPs were selected based on the highest minor allele frequency (MAF) in African crossbred populations assuming two Scenarios: (1) parents were selected among all the animals with known genotypes, and (2) parents were selected only among the animals known to be a parent of at least one progeny. RESULTS For the medium-density genotype data, SNPs selected for the largest differences in allele frequency between West African indigenous and European Bos taurus breeds performed best for most African crossbred populations and achieved a prediction accuracy (r2) for breed composition of 0.926 to 0.961 with 200 SNPs. For the high-density dataset, a panel with 70% of the SNPs selected on their largest difference in allele frequency between African and European Bos taurus performed best or very near best across all crossbred populations with r2 ranging from 0.978 to 0.984 with 200 SNPs. In all African crossbred populations, unambiguous parentage assignment was possible with ≥ 300 SNPs for the majority of the panels for Scenario 1 and ≥ 200 SNPs for Scenario 2. CONCLUSIONS The identified low-cost SNP assays could overcome incomplete or inaccurate pedigree records in African smallholder systems and allow effective breeding decisions to produce progeny of desired breed composition.
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Affiliation(s)
- Netsanet Z. Gebrehiwot
- Centre for Genetic Analysis and Applications, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351 Australia
| | - Eva M. Strucken
- Centre for Genetic Analysis and Applications, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351 Australia
| | - Karen Marshall
- International Livestock Research Institute and Centre for Tropical Livestock Genetics and Health, Nairobi, Kenya
| | - Hassan Aliloo
- Centre for Genetic Analysis and Applications, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351 Australia
| | - John P. Gibson
- Centre for Genetic Analysis and Applications, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351 Australia
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