200 likes | 322 Views
Predicting Genetic Merit Using Genomic Data. How Related are Relatives?. Example: Full sibs are expected to share 50% of their DNA on average may actually share 40% to 60% of their DNA because each inherits a different mixture of chromosome segments from the two parents.
E N D
How Related are Relatives? • Example: Full sibs • are expected to share 50% of their DNA on average • may actually share 40% to 60% of their DNA because each inherits a different mixture of chromosome segments from the two parents. • Exact DNA sharing computed from genotypes instead of pedigrees
Genomic Pedigree1 chromosome atagatcgatcg ctgtagcgatcg ctgtagcttagg agatctagatcg agggcgcgcagt cgatctagatcg ctgtctagatcg atgtcgcgcagt cggtagatcagt agagatcgcagt agagatcgatct atgtcgctcacg atggcgcgaacg ctatcgctcagg
Genotype Data for ElevationChromosome 1 1000111220020012111011112111101111001121100020122002220111 1202101200211122110021112001111001011011010220011002201101 1200201101020222121122102010011100011220221222112021120120 2010020220200002110001120201122111211102201111000021220200 0221012020002211220111012100111211102112110020102100022000 2201000201100002202211022112101121110122220012112122200200 0200202020122211002222222002212111121002111120011011101120 0202220001112011010211121211102022100211201211001111102111 2110211122000101101110202200221110102011121111011202102102 1211011022122001211011211012022011002220021002110001110021 1021101110002220020221212110002220102002222121221121112002 0110202001222222112212021211210110012110110200220002001002 0001111011001211021212111201010121202210101011111021102112 2111111212111210110120011111021111011111220121012121101022 202021211222120222002121210121210201100111222121101
Gene Flow • Descendants of 1 bull (Elevation) • Born in 1965 • 80,000 daughters • 2.3 million granddaughters • 6.5 million great-granddaughters • 15.2% of genes in US Holsteins • Appears in >80% of Holstein pedigrees in every country studied
Sequencing and Genotyping • Cattle genome sequenced in 2004 • 30 chromosome pairs (including X,Y) • 3 billion letters from each parent • Illumina BovineSNP50 BeadChip • 58,000 genetic markers in 2007 • 38,416 used in genomic predictions • Current cost <$250 per animal
Experimental Design • Compute genomic evaluations and parent averages from 2003 data • 3576 older Holstein bulls born 1952-1998 • Compare ability to predict daughter performance in 2008 data • 1759 younger bulls born 1999-2002 • Test results for 27 traits: 5 yield, 5 health, 16 conformation, and Net Merit
Value of Genotyping More SNP9,604 (10K), 19,208 (20K), and 38,416 (40K) SNP REL of PA = reliability of parent average
Top Net Merit Bull:O-Man • Semen sales 198,000 units / year • Semen price $40 / unit • Income ~$35 million to date • 25,429 daughters already milking • 19,848 in United States • 1,348 in France, 1,108 in Italy, 946 in Denmark, 527 in the Netherlands, etc.
Genetic ProgressHolsteins • Assume 60% REL for net merit • Sires mostly 2 instead of 6 years old • Dams of sons mostly genotyped heifers instead of cows with phenotype and genotype • Progress could increase by >50% • 0.37 vs. 0.23 genetic SD per year • Reduce generation interval more than accuracy
Conclusions • Genomic predictions significantly better than parent average (P < .0001) for all 26 traits tested • Gains in reliability equivalent on average to 11 daughters with records • High reliability requires many genotypes and phenotypes • 5,335 genotyped bulls had >10 million daughters with phenotypic (milk yield) data
Acknowledgments • Genotyping and DNA extraction: • BFGL, U. Missouri, U. Alberta, GeneSeek, GIFV, and Illumina • Computing: • AIPL staff (George Wiggans, Mel Tooker, Leigh Walton, etc.) • Funding: • National Research Initiative grants • 2006-35205-16888, 2006-35205-16701 • Agriculture Research Service • Contributors to Cooperative Dairy DNA Repository (CDDR)
Citizens Fed / AcreData from year 2000, 1 acre = .435 hectare