Characteristics and use of the Illumina BovineLD and GeneSeek Genomic Profiler low-density bead chips for genomic evaluation

The GeneSeek Genomic Profiler (GGP) BeadChip (GeneSeek, Lincoln, NE), which became available commercially in February 2012, is based on the Illumina BovineLD Genotyping BeadChip (Illumina Inc., San Diego, CA), with 1,745 additional single nucleotide polymorphisms (SNP) for genomic evaluation and SNP for proprietary single-gene tests. The BovineLD chip with 6,909 SNP, which replaced the Illumina GoldenGate Bovine3K Genotyping BeadChip, has been available since October 2011. The GGP's additional SNP for genomic evaluation were selected to improve imputation by filling SNP gaps on chromosomes and including more Bovine3K SNP than were on the BovineLD chip and to impute microsatellite alleles to facilitate parentage validation. The SNP for single-gene tests were included to minimize the number of separate tests required for those genes, particularly for bulls. The September 2012 US national genomic evaluation included genotypes from BovineLD and GGP chips for 82,510 animals. For those data, BovineLD and GGP performance was similar. The call rate for SNP on these chips that were used in genomic evaluation was 99.6%. The 9 Y-chromosome SNP in common on the BovineLD and GGP chips were highly effective in sex validation (call rate of 99% for males and 0.01% for females). For both chips, the rate of parent-progeny conflicts on a SNP basis (<= 0.004%) was similar to that for SNP on the Illumina BovineSNP50 Genotyping BeadChip. Imputation accuracy for 45,187 BovineSNP50 SNP averaged 99.4% for Holsteins. Imputation accuracy was slightly higher for the GGP chip compared with the BovineLD chip because of its additional SNP. Reliability for genomic evaluations using BovineLD and GGP genotypes was 3 percentage points higher than that for Bovine3K genotypes.