section_path: Genetics
section_name: Genetics
paragraph_text: Genetics
  
  In 2009, the National Institutes of Health and the US Department of Agriculture reported having mapped the bovine genome. Cattle have some 22,000 genes, of which 80% are shared with humans; they have about 1000 genes that they share with dogs and rodents, but not with humans. Using this bovine "HapMap", researchers can track the differences between breeds that affect meat and milk yields. Early research focused on Hereford genetic sequences; a wider study mapped a further 4.2% of the cattle genome.
  
  Behavioral traits of cattle can be as heritable as some production traits, and often, the two can be related. The heritability of temperament (response to isolation during handling) has been calculated as 0.36 and 0.46 for habituation to handling. Rangeland assessments show that the heritability of aggressiveness in cattle is around 0.36.
  
  Quantitative trait loci have been found for a range of production and behavioral characteristics for both dairy and beef cattle.