SNP (Single Nucleotide Polymorphism)
|SNP (Single Nucleotide Polymorphism)||
Term describing single points in DNA sequence that differ between animals. The vast majority of the DNA sequence is the identical in all cattle (and people and mice for that matter). There are some locations in the DNA sequence where a single base or a nucleotide (adenine (A), guanine (G), thymine (T), or cytosine (C)) differs from one individual to another. For instance, Bull A may have a DNA sequence of A-G-T-T-C and Bull B may have a sequence of A-G-A-T-C. In this instance, the third base is not the same between these individuals and is called a SNP (pronounced "snip"). There are thousands of SNPs that tell us about an individual's genetic potential or relationship to another individual. The ASA has done 50K SNP testing (50,000 SNP markers) with GeneSeek in the past and now offers the GGP-HD profile (GeneSeek Genomic Profiler- high density) with 80,000 SNP markers. The resulting SNP information is included in the ASA genetic evaluation and provides molecular breeding values (MBVs). Knowing these MBVs can improve the accuracy of EPDs by an equivalent of several progeny records depending on the trait. This is particularly true in young animals that have lower progeny counts and, therefore, low accuracy EPDs.