COMPARATIVE-ANALYSIS OF 82 EXPRESSED SEQUENCE TAGS FROM A CATTLE OVARY CDNA LIBRARY

In total, 82 ESTs were generated from 51 unique clones randomly select ed from a cattle ovary cDNA library. Among these clones, 22 (42.1%) ha d 5' and/or 3' ends that matched with known human or other mammalian c oding sequences, 18 (35.3%) matched human or other ESTs, and 11 (21.6% ) represented novel transcripts with no significant match to any seque nce in the databases. The relatively high frequency of ESTs with no ma tches in GenBank or dbEST indicates that bovine ovary may be a source of novel candidate genes for loci affecting cattle reproduction traits . Primers were designed for 11 ESTs that had human orthologs in GenBan k. These ESTs were mapped to 10 bovine autosomes by PCR screening of a somatic cell hybrid panel. Among these 11 ESTs, 4 corresponded to gen es previously mapped in humans and had chromosome assignments on the b ovine map that were consistent with available comparative mapping data . Although the human orthologs of the remaining 7 mapped bovine ESTs h ave not been mapped, the human map location could be predicted on the basis of existing comparative mapping data. Because of the general uti lity of our approach for comparative genome analysis, we have termed i t comparative mapping by annotation and sequence similarity (COMPASS). With the cost of large-scale EST sequencing becoming more affordable, and the rapid expansion of DNA databases, it is likely that COMPASS w ill be a preferred strategy for high throughput comparative mapping.