The cow, dog and a single-celled genetic powerhouse called Oxytricha trifallax are the latest organisms to be named as high priorities for genome sequencing by the US National Human Genome Research Institute in Bethesda, Maryland.
On 11 September, the institute announced its second round of sequencing priorities, having asked researchers to submit 'white papers' making the case for their favourite organisms. The newcomers join the chicken, chimpanzee, honeybee, the sea urchin Strongylocentrotus purpuratus, the protozoan Tetrahymena thermophila and 15 species of fungi (see Nature 417, 473–474; 200210.1038/417473a).
Steven Kappes, director of the US Department of Agriculture's Meat Animal Research Center in Clay Center, Nebraska, says that the cow offers “another avenue” to identify important mammalian genes. Whereas biomedical researchers use lab animals primarily as models of human disease, agricultural scientists tend to focus on normal processes such as muscle development and reproduction.
Man's best friend, however, shares many of our maladies. The dog's supporters touted the animal as a model for various diseases, including cancer, heart disease and deafness.
The protozoan Oxytricha, meanwhile, is an evolutionary oddity. It seems to package each of its 30,000 genes into a tiny individual chromosome. Each time it divides, it spits out accumulated 'junk' DNA. As a result, Oxytricha crams about the same number of genes as the mouse into a genome some 60 times smaller.
Oxytricha had previously been ranked as a moderate priority, alongside the rhesus macaque — to the bitter disappointment of researchers who use this monkey in biomedical research. The macaque genome proposal will be resubmitted in October.