Isolation and characterization of hepatic and intestinal expressed sequence tags potentially involved in trait differentiation between cows of different metabolic type

mRNA differential display was applied to identify hepatic and intestinal ex pressed sequence tags (ESTs) in lactating cows of different metabolic types (milk type, meat/milk type, meat type) that art: potentially associated wi th energy turnover and involved in the regulation of these processes. Altog ether, 277 ESTs (liver: 161, intestine: 116) were identified. For 150 trans cripts (liver: 99, intestine: 51), the sequences showed similarity to previ ously described genes and ESTs. Many of these homologous sequences are repo rted to be involved in hepatic metabolism. Ninety-four ESTs (liver: 43, int estine: Sl)did not match with any database entries. Semi-quantitative RT-PC R revealed quantitative differences in transcript represented by randomly c hosen ESTs in liver samples of animals of the Holstein and Charolais breeds . One hundred twenty-two ESTs were mapped physically by using a bovine-hams ter somatic cell hybrid panel (SCP) and a 5000-rad bovine whole genome radi ation hybrid panel (WGRH). These ESTs were assigned to the bovine syntenic groups and positioned in the recently established RH-based ordered comparat ive map of the cattle and human genomes. The mapped, differentially express ed sequence tags are a useful prerequisite for cloning of genetic variation underlying economic traits.