Population Structure & Genetic Improvement in Livestock

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Population Structure & Genetic Improvement in Livestock Heather J. Huson, Ph.D. Cornell University Department of Animal Science Robert & Anne Everett Endowed Professorship in Dairy Cattle Genetics

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The genetic improvement of livestock has been a hot topic for almost a century, bringing together researchers, industry, and producers to work towards a common goal. Many countries currently employ extensive genetic selection programs in their cattle with pigs, sheep, and chicken close behind. In this webcast, Heather J. Huson, Ph.D. from Cornell University will focus on population dynamics and trait association in cattle and goats using high density SNP datasets. Population structure plays a critical role in understanding the relatedness among livestock, ancestral origins of traits, and identification of unique sub-populations or breeds for production improvement and conservation. This also lays the foundation for understanding and improving species such as the goat which is a vital food source in developing countries but has little recorded production or health data. Understanding population structure is essential for designing complex trait association studies such as those related to production and health characteristics. Here, Huson shows examples of her lab's investigation into population structure in both goats and cattle to identify distinct groups and study traits such as thermo-tolerance.

Transcript of Population Structure & Genetic Improvement in Livestock

  • 1. Population Structure & GeneticImprovement in LivestockHeather J. Huson, Ph.D.Cornell UniversityDepartment of Animal ScienceRobert & Anne Everett Endowed Professorship in Dairy Cattle Genetics

2. OverviewResearch focus Population structure Trait associationResearch projects Thermo-tolerance in tropical cattle African Goat Improvement ProjectResearch goal Genetic improvement of livestock 3. THERMO-TOLERANCE INTROPICAL CATTLE 4. Thermo-tolerance in Tropical Cattle Importance of thermo-tolerance in cattle Milk Production Reproduction SLICK hair-coat: short, fine, sleek hair-coat found intropically adapted cattle Objective: improve diagnostic markers & identifycausative mutationSenepolSt. CroixRomosinuanoVenezuelaCaroraVenezuela 5. Research Roll Identify breed relationship of SLICK- tropicalcattle Investigate ancestral origins of SLICK- haircoat Conduct the Genome-wide associationanalysis of SLICK phenotype 6. Research Approach Use a variety of analyses to assess traitassociation across the genome Runs Of Homozygosity Signatures of selection (iHS) Genome-wide Association Study Haplotype blocks 7. Ancestry of Senepol cattleRed PollNDamaEastAfricanZebu Composite Breed of theSt. Croix Virgin IslandSenepol 8. Genomic verification of Senepol ancestryNDama Red Poll Senepol ZebuK=4 9. GWAS of SLICK hair-coatUse ancestral breeds as controls to balance SLICKcasesCases= 72 Controls= 61 Senepol-2 Red Pole-10 NDama-10 Zebu- 10 Senepol x Angus-1 Senepol/Angus x Angus-1 Angus-10 Holstein- 7 Brown Swiss- 10 Senepol- 36 Senepol x Angus-3 Senepol/Angus x Angus-1 Romosinuano- 2 Romosinuano/Angus xAngus-1 Romosinuano x Angus-11 Holstein x Senepol- 7 Carora- 10 10. GWAS of SLICK hair-coat639,663SNPsMinimal Correction for Relatedness orPopulation Structure-log10p = 5-log10p = ~16.5 11. Improved GWAS of SLICK hair-coatEMMAX Kinship Matrix- Correction forRelatedness / Population Structure-log10p = 5-log10p = ~12.8 12. Runs of HomozygosityDr. Eui-Soo Kim, Iowa State UniversitySNP Threshold Approximate distance100 consecutive SNPs 0.3 Mb200 0.6300 1.0500 1.6 13. Haplotype Blocks 24 significantly associated haplotype patterns 3 haplotype patterns identified only in SLICKBlock ID Start bp End bpBlockDistance(bp) HaplotypeFrequencySLICKFrequencyNon-SLICK P Value94 37718791 37721846 3,055 GGG 0.833 0.314 3.58E-12104 37940179 37957238 17,059 GGGGA 0.292 0 4.96E-10112 38224054 38281493 57,439 GGGGAGG 0.278 0 1.44E-09143 39469953 39508807 38,854 GGGAGGGCAGCGGGAGGAGA 0.264 0 4.06E-09 14. Multiple Genetic AnalysesBTA 2037 Mb 40 MbSKP2 SPEF2Keratinocyteproliferation and skinhomeostasisSpermatogenesis defects.Late feathering in male chickens.PRLR Hair cycling andlocalized to skin tissue 15. Outcomes Breed relationship and ancestry of SLICK-hairedtropical cattle Narrowed SLICK locus to 0.5 Mb on BTA 20 Identified new diagnostic markers 3 haplotypes found only in SLICK hairedindividuals Huson et al. Frontiers in Genetics, March2014 16. Future Directions Potentially 2 mutations effecting same gene Related to breeds Sequencing region to determine causative mutation Genotyping additional SLICK breedsSenepolSt. CroixRomosinuanoVenezuelaCaroraVenezuela 17. USAID: Feed the Future InitiativeAFRICAN GOAT IMPROVEMENTNETWORK (AGIN) 18. Global Food Security 90% of global population located in Hunger Zones Target: African small-holder farmersGOATSGOATS 19. Why Goats? Most common livestock species in Africa Small-holder farmers (women) Diverse & hardy species Thrive in harsh climates with sparse forage Large potential growth with selection Economically efficient 20. SAMPLING STATUS 21. Total Sampling Dataset16 Countries> 60 Sampling Sites~ 66 Breeds/Populations> 2,737 Goats Sampled 22. EgyptEthiopiaKenyaTanzaniaMalawiZimbabweSouth AfricaMozambiqueNigeriaCameroonUgandaBreeds sampledwithin Africa 11 African countriessampled 4 new FAO researchprojects being added 23. Global ComparisonUS: Spanish derivedNew Zealand: BoerTurkey: domesticationBrazil: climate, parasiteItaly: dairy breedsItalyNOAA: http://www.ngdc.noaa.gov/mgg/global/global.htmlUnitedStatesTurkeyBrazilNew Zealand 24. PHENOTYPING 25. Standardized Sampling Protocol Geographical information system (GIS) data Latitude, longitude, elevation Physical body measurements Chest girth, height, length, shoulder width, pin-bonewidth, weight Photo characterization Biological sample (DNA)Shot 5: TeethshotShot 6:FAMACHAshot 26. Variation inbody size 27. Is there a significance to size variationof breeds across different countries? 28. BoerCountry # GoatsMalawi 18Mozambique 2Tanzania 13Uganda 6Zimbabwe 31USA 15Points of Note:USA- Are individualssignificantly heavier?Mozambique- only 2individualsSouth Africa???Develop plan to pursueBoer investigation 29. EthiopiaGumezKeffaAbergelleWoyito GujiBreed # GoatsAbergelle 64Gumez 53Keffa 50Woyito Guji 50 30. Ethiopian Goats 31. GENOTYPING STATUS 32. Quality Control Filtering11 Countries, ~41 breeds/populations952 individuals53,347 SNPsSNP Filtering51,543 SNPsCall rate < 0.9, > 2 alleles, MAF 2 alleles, MAF < 0.02Sample Filtering895 individualsCall rate < 0.9895 individuals51,543 SNPs 34. Quality Control Filtering11 Countries, ~41 breeds/populations952 individuals53,347 SNPsSNP Filtering51,543 SNPsCall rate < 0.9, > 2 alleles, MAF < 0.02Sample Filtering895 individualsCall rate < 0.9895 individuals51,543 SNPs 35. Quality Control Filtering11 Countries, ~41 breeds/populations952 individuals53,347 SNPsSNP Filtering51,543 SNPsCall rate < 0.9, > 2 alleles, MAF