CHARACTERIZATION OF GENE-EXPRESSION IN MOUSE BLASTOCYST USING SINGLE-PASS SEQUENCING OF 3995 CLONES

To study the gene expression profile in the mouse blastocyst and to id entify embryonic stage-specific genes, we randomly selected cDNAs deri ved from mouse blastocysts and sequenced a total of 3995 clones from o ne or both ends. Excluding the uninformative clones, 3395 clones were grouped as 937 different kinds of genes. Among these, 465 and 406 spec ies showed similarity to known genes and expressed sequence tags (ESTs ), respectively, whereas 66 species showed no significant similarity t o any genes in known databases. Analysis of these cDNAs revealed that this library contained a variety of functional genes as well as genes that have not been detected in the human EST database; it should provi de us with a useful resource for molecular analysis of developmental m echanisms. Although the human EST project is considered to represent r oughly half of all genes, our findings indicate that many early stage developmental genes remain to be identified. (C) 1998 Academic Press.