New tools for genomic selection in dairy cattle
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This document summarizes John Cole's presentation on new genomic tools for dairy cattle. Some key points: 1) Genomic selection works well in dairy cattle due to extensive historical data, genetic evaluation programs, widespread AI use, and high-value animals. Genomics can reduce generation intervals. 2) Different genotyping arrays like BovineSNP50 and BovineHD are used, with over 300,000 animals genotyped as of 2013. 3) Genomic predictions provide information equivalent to dozens of progeny, improving reliability of selection, especially for lowly heritable traits. This allows more rapid genetic improvement.
New tools for genomic selection in dairy cattle
- 1. John B. Cole Animal Improvement Programs Laboratory Agricultural Research Service, USDA Beltsville, MD 20705-2350 john.cole@ars.usda.gov New tools for genomic selection in dairy cattle
- 2. Department of Animal Sciences, Purdue University, October 23, 2013 (2) Cole Why genomic selection works in dairy Extensive historical data available Well-developed genetic evaluation program Widespread use of AI sires Progeny test programs High-valued animals, worth the cost of genotyping Long generation interval which can be reduced substantially by genomics
- 3. Department of Animal Sciences, Purdue University, October 23, 2013 (3) Cole Illumina genotyping arrays • BovineSNP50 • 54,001 SNPs (version 1) • 54,609 SNPs (version 2) • 45,187 SNPs used in evaluation • BovineHD • 777,962 SNPs • Only BovineSNP50 SNPs used • >1,700 SNPs in database • BovineLD • 6,909 SNPs • Allows for additional SNPs BovineSNP50 v2 BovineLD BovineHD
- 4. Department of Animal Sciences, Purdue University, October 23, 2013 (4) Cole Genotyped animals (April 2013) Chip Traditional evaluation? Animal sex Holstein Jersey Brown Swiss Ayrshire 50K Yes Bulls 21,904 2,855 5,381 639 Cows 16,062 1,054 110 3 No Bulls 45,537 3,884 1,031 325 Cows 32,892 660 102 110 <50K Yes Bulls 19 11 28 9 Cows 21,980 9,132 465 0 No Bulls 14,026 1,355 90 2 Cows 158,622 18,722 658 105 Imputed Yes Cows 2,713 237 103 12 No Cows 1,183 32 112 8 All 314,938 37,942 8,080 1,213 362,173
- 5. Department of Animal Sciences, Purdue University, October 23, 2013 (5) Cole Marketed Holstein bulls 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 2007 2008 2009 2010 2011 %oftotalbreedings Breeding year Old non-G Old G First crop non-G First crop G Young Non-G Young G
- 6. Department of Animal Sciences, Purdue University, October 23, 2013 (6) Cole What’s a SNP genotype worth? For the protein yield (h2=0.30), the SNP genotype provides information equivalent to an additional 34 daughters Pedigree is equivalent to information on about 7 daughters
- 7. Department of Animal Sciences, Purdue University, October 23, 2013 (7) Cole And for daughter pregnancy rate (h2=0.04), SNP = 131 daughters What’s a SNP genotype worth?
- 8. Department of Animal Sciences, Purdue University, October 23, 2013 (8) Cole Genotypes and haplotypes • Genotypes indicate how many copies of each allele were inherited • Haplotypes indicate which alleles are on which chromosome • Observed genotypes partitioned into the two unknown haplotypes • Pedigree haplotyping uses relatives • Population haplotyping finds matching allele patterns
- 9. Department of Animal Sciences, Purdue University, October 23, 2013 (9) Cole Haplotyping program – findhap.f90 • Begin with population haplotyping • Divide chromosomes into segments, ~250 to 75 SNP / segment • List haplotypes by genotype match • Similar to fastPhase, IMPUTE • End with pedigree haplotyping • Detect crossover, fix noninheritance • Impute nongenotyped ancestors
- 10. Department of Animal Sciences, Purdue University, October 23, 2013 (10) Cole Example Bull: O-Style (USA137611441) • Read genotypes and pedigrees • Write haplotype segments found • List paternal / maternal inheritance • List crossover locations
- 11. Department of Animal Sciences, Purdue University, October 23, 2013 (11) Cole O-Style Haplotypes Chromosome 15
- 12. Department of Animal Sciences, Purdue University, October 23, 2013 (12) Cole Loss-of-function mutations • At least 100 LoF per human genome surveyed (MacArthur et al., 2010) • Of those genes ~20 are completely inactivated • Uncharacterized LoF variants likely to have phenotypic effects • How should mating programs deal with this? • Can we find them?
- 13. Department of Animal Sciences, Purdue University, October 23, 2013 (13) Cole Recessive defect discovery • Check for homozygous haplotypes • 7 to 90 expected but none observed • 5 of top 11 are potentially lethal • 936 to 52,449 carrier sire by carrier MGS fertility records • 3.1% to 3.7% lower conception rates • Some slightly higher stillbirth rates • Confirmed Brachyspina same way
- 14. Department of Animal Sciences, Purdue University, October 23, 2013 (14) Cole Haplotypes affecting fertility & stillbirth Name Chromosome Location Haplotype Freq Earliest Known Ancestor HH1 5 63150400 1.9 Pawnee Farm Arlinda Chief HH2 1 94.8-96.5 1.6 Willowholme Mark Anthony HH3 8 95410507 2.9 Glendell Arlinda Chief, Gray View Skyliner HH4 1 1,277,227 0.37 Besne Buck HH5 9 92-94 2.22 Thornlea Texal Supreme JH1 15 11-16 12.1 Observer Chocolate Soldier BH1 7 42-47 6.67 West Lawn Stretch Improver BH2 19 10-12 7.78 Rancho Rustic My Design AH1 17 65.9-66.2 11.8 Selwood Betty’s Commander
- 15. Department of Animal Sciences, Purdue University, October 23, 2013 (15) Cole Precision mating Eliminate undesirable haplotypes Detection at low allele frequencies Avoid carrier-to-carrier matings Easy with few recessives, difficult with many recessives Include in selection indices Requires many inputs Use a selection strategy for favorable minor alleles (Sun & VanRaden, 2013)
- 16. Department of Animal Sciences, Purdue University, October 23, 2013 (16) Cole Sequencing successes at AIPL/BFGL • Simple loss-of-function mutations • APAF1 (HH1) – Spontaneous abortions in Holstein cattle (Adams et al., 2012) • CWC15 (JH1) – Early embryonic death in Jersey cattle (Sonstegard et al., 2013) • Weaver syndrome – Neurological degeneration and death in Brown Swiss cattle (McClure et al., 2013)
- 17. Department of Animal Sciences, Purdue University, October 23, 2013 (17) Cole Modified pedigree & haplotype design Bull A (1968) AA, SCE: 8 Bull B (1962) AA, SCE: 7 MGS Bull H (1989) Aa, SCE: 14 Bull I (1994) Aa, SCE: 18 Bull E (1982) Aa, SCE: 8 Bull F (1987) Aa, SCE: 15 Bull C (1975) AA, SCE: 8 δ = 10 Bull E (1974) Aa, SCE: 10 MGS Bull J (2002) Aa, SCE: 6 Bull K (2002) Aa, SCE: 15 Bull K (2002) aa, SCE: 15 These bulls carry the haplotype with the largest, negative effect on SCE: Bull D (1968) ??, SCE: 7 Couldn’t obtain DNA:
- 18. Department of Animal Sciences, Purdue University, October 23, 2013 (18) Cole Things can move quickly! ● Dead calves will be genotyped for BH2 status ● If homozygous, we will sequence in a family-based design ● Austrian group also working on BH2 (Schwarzenbacher et al., 2012) ● Strong industry support! Semen in CDDR Tissue samples (ears) being processed for DNA Owner will collect blood samples when born Owner will collect blood samples AI firm sending 10 units of semen Brown Swiss family with possible BH2 homozygotes (dead)
- 19. Department of Animal Sciences, Purdue University, October 23, 2013 (19) Cole Our industry wants new genomic tools
- 20. Department of Animal Sciences, Purdue University, October 23, 2013 (20) Cole We already have some tools https://www.cdcb.us/Report_Data/Marker_Effects/marker_effects.cfm`
- 21. Department of Animal Sciences, Purdue University, October 23, 2013 (21) Cole Chromosomal DGV query https://www.cdcb.us/CF- queries/Bull_Chromosomal_EBV/bull_chromosomal_ebv.cfm
- 22. Department of Animal Sciences, Purdue University, October 23, 2013 (22) Cole Now we have a new haplotype query https://www.cdcb.us/CF- queries/Bull_Chromosomal_EBV/bull_chromosomal_ebv.cfm
- 23. Department of Animal Sciences, Purdue University, October 23, 2013 (23) Cole Paternal and maternal DGV • Shows the DGV for the paternal and maternal haplotyles • Imputed from 50K using findhap.f90 v.2 • Can we use them to make mating decisions? • People are going to do it – we need to help them! • Who is actually making planned matings?
- 24. Department of Animal Sciences, Purdue University, October 23, 2013 (24) Cole Top net merit bull August 2013 COOKIECUTTER PETRON HALOGEN (HO840003008710387, PTA NM$ +926, Rel 68%)
- 25. Department of Animal Sciences, Purdue University, October 23, 2013 (25) Cole Pluses and minuses 23 positive chromosomes 19 negative chromosomes
- 26. Department of Animal Sciences, Purdue University, October 23, 2013 (26) Cole Breeders need MS variance
- 27. Department of Animal Sciences, Purdue University, October 23, 2013 (27) Cole The good and the bad Chromosome 1
- 28. Department of Animal Sciences, Purdue University, October 23, 2013 (28) Cole The best we can do DGV for NM$ = +2,314
- 29. Department of Animal Sciences, Purdue University, October 23, 2013 (29) Cole The worst we can do DGV for NM$ = -2,139
- 30. Department of Animal Sciences, Purdue University, October 23, 2013 (30) Cole Dominance in mating programs Quantitative model Must solve equation for each mate pair Genomic model Compute dominance for each locus Haplotype the population Calculate dominance for mate pairs Most genotyped cows do not yet have phenotypes
- 31. Department of Animal Sciences, Purdue University, October 23, 2013 (31) Cole Inbreeding effects Inbreeding alters transcription levels and gene expression profiles (Kristensen et al., 2005). Moderate levels of inbreeding among active bulls (7.9 to 18.2) Are inbreeding effects distributed uniformly across the genome? Can we find genomic regions where heterozygosity is necessary or not using the current population?
- 32. Department of Animal Sciences, Purdue University, October 23, 2013 (32) Cole Precision inbreeding • Runs of homozygosity may indicate genomic regions where inbreeding is acceptable • Can we target those regions by selecting among haplotypes? Dominance RecessivesUnder-dominance
- 33. Department of Animal Sciences, Purdue University, October 23, 2013 (33) Cole Challenges with new phenotypes Lack of information Inconsistent trait definitions Often no database of phenotypes Many have low heritabilities Lots of records are needed for accurate evaluation Genetic improvement can be slow Genomics may help with this
- 34. Department of Animal Sciences, Purdue University, October 23, 2013 (34) Cole Reliability with and without genomics Event EBV Reliability GEBV Reliability Gain Displaced abomasum 0.30 0.40 +0.10 Ketosis 0.28 0.35 +0.07 Lameness 0.28 0.37 +0.09 Mastitis 0.30 0.41 +0.11 Metritis 0.30 0.41 +0.11 Retained placenta 0.29 0.38 +0.09 Average reliabilities of sire PTA computed with pedigree information and genomic information, and the gain in reliability from including genomics. Example: Dairy cattle health (Parker Gaddis et al., 2013)
- 35. Department of Animal Sciences, Purdue University, October 23, 2013 (35) Cole Some novel phenotypes being studied Age at first calving (Cole et al., 2013) Dairy cattle health (Parker Gaddis et al., 2013) Methane production (de Haas et al., 2011) Milk fatty acid composition (Bittante et al., 2013) Persistency of lactation (Cole et al., 2009) Rectal temperature (Dikmen et al., 2013) Residual feed intake (Connor et al., 2013)
- 36. Department of Animal Sciences, Purdue University, October 23, 2013 (36) Cole What do we do with novel traits? • Put them into a selection index • Correlated traits are helpful • Apply selection for a long time • There are no shortcuts • Collect phenotypes on many daughters • Repeated records of limited value • Genomics can increase accuracy
- 37. Department of Animal Sciences, Purdue University, October 23, 2013 (37) Cole Trait Relative value (%) Net merit Cheese merit Fluid merit Milk (lb) 0 –15 19 Fat (lb) 19 13 20 Protein (lb) 16 25 0 Productive life (PL, mo) 22 15 22 Somatic cell score (SCS, log2) –10 –9 –5 Udder composite (UC) 7 5 7 Feet/legs composite (FLC) 4 3 4 Body size composite (BSC) –6 –4 –6 Daughter pregnancy rate (DPR, %) 11 8 12 Calving ability (CA$, $) 5 3 5 Genetic-economic indexes 2010 revision
- 38. Department of Animal Sciences, Purdue University, October 23, 2013 (38) Cole Trait Relative emphasis on traits in index (%) PD$ 1971 MFP$ 1976 CY$ 1984 NM$ 1994 NM$ 2000 NM$ 2003 NM$ 2006 NM$ 2010 Milk 52 27 –2 6 5 0 0 0 Fat 48 46 45 25 21 22 23 19 Protein … 27 53 43 36 33 23 16 PL … … … 20 14 11 17 22 SCS … … … –6 –9 –9 –9 –10 UDC … … … … 7 7 6 7 FLC … … … … 4 4 3 4 BDC … … … … –4 –3 –4 –6 DPR … … … … … 7 9 11 SCE … … … … … –2 … … DCE … … … … … –2 … … CA$ … … … … … … 6 5 Index changes
- 39. Department of Animal Sciences, Purdue University, October 23, 2013 (39) Cole What does it mean to be the worst? • Large body size • Eats a lot of expensive feed • Average fertility…or worse! • Begin first lactation with dystocia • Bull calf (sexed semen?) • Retained placenta, metritis, etc. • Mediocre production • Uses many resources, produces very little
- 40. Department of Animal Sciences, Purdue University, October 23, 2013 (40) Cole Dissecting genetic correlations • Compute DGV for 75-SNP segments • Calculate correlations of DGV for traits of interest for each segment • Is there interesting biology associated with favorable correlations? • …and what about linkage disequilibrium?
- 41. Department of Animal Sciences, Purdue University, October 23, 2013 (41) Cole SNP segment correlations Milk with DPR Unfavorable associations Unfavorable associationsFavorable associations Favorable associations
- 42. Department of Animal Sciences, Purdue University, October 23, 2013 (42) Cole SNP segment correlations Dist’n over genome
- 43. Department of Animal Sciences, Purdue University, October 23, 2013 (43) Cole Highest correlations for milk and DPR Obs chrome seg tloc corr 1 18 449 1890311910 0.53090 2 18 438 1845503211 0.51036 3 8 233 990810677 0.49199 4 26 557 2331662169 0.47173 5 2 60 239796003 0.46507 6 29 596 2483178230 0.45252 7 14 366 1544999648 0.43817 8 2 65 269016505 0.41022 9 11 298 1255667282 0.39734 10 20 469 1971347760 0.3919
- 44. Department of Animal Sciences, Purdue University, October 23, 2013 (44) Cole Conclusions Non-additive effects may be useful for increasing selection intensity while conserving important heterozygosity Whole-genome sequencing has been very successful at helping economically important loss-of-function mutations Novel phenotypes are necessary to address global food security and a changing climate
- 45. Department of Animal Sciences, Purdue University, October 23, 2013 (45) Cole Acknowledgments Paul VanRaden, George Wiggans, Derek Bickhart, Dan Null, and Tabatha Cooper Animal Improvement Programs Laboratory, ARS, USDA Beltsville, MD Tad Sonstegard, Curt Van Tassell, and Steve Schroeder Bovine Functional Genomics Laboratory, ARS, USDA, Beltsville, MD Chuanyu Sun National Association of Animal Breeders Beltsville, MD Dan Gilbert New Generation Genetics Inc., Fort Atkinson, WI
- 46. Department of Animal Sciences, Purdue University, October 23, 2013 (46) Cole Questions? http://gigaom.com/2012/05/31/t-mobile-pits-its-math-against-verizons-the-loser-common-sense/shutterstock_76826245/