Mapping of 16 ESTs expressed in the bovine mammary gland during lactation

A bovine mammary gland cDNA-library was used to characterize and map genes expressed during lactation. Fifty cDNA clones selected by differential hybr idization were sequenced from both ends, and sequences were examined for si milarities with database sequences. For 34 of the transcripts, the sequence s showed more than 80% similarity to previously characterized genes or expr essed sequence tags (ESTs). Twenty cDNAs chat could be of interest as candi date genes for milk production are selected for genetic or chromosomal mapp ing. Twenty; three out of the 39 designed primer pairs representing 16 cDNA clones amplified the expected fragments and were used for subsequent fluor escent single-strand conformation polymorphism analysis (F-SSCP) in the Int ernational Bovine Reference panel families (IBRP). Ten polymorphic loci cou ld be identified and used to genotype the IBRP animals, and nine of them we re subsequently genetically mapped on nine chromosomes, in addition, eight loci from the 16 cDNA clones could be mapped by somatic cell hybrids, bring ing the total number of mapped genes to 16, one of which was mapped genetic ally as well as physically. The mapped mammary gland ESTs are potentially u seful for cloning economic trait loci by a positional candidate gene clonin g approach.