gene expression differences in oocytes derived from adult and prepubertal japanese black cattle during in vitro maturation the present study was carried out to compare the gene expression profiles in oocytes derived from adult and prepubertal japanese black cattle during in vitro maturation ivm using microarray gene chips bovine genome array containing 24072 probe sets representing over 23000 transcripts microarray experiments were conducted using total rna isolated from immature germinal vesicle gv and in vitro matured metaphase ii mii oocytes derived from adult and prepubertal animals a total of 333 14 and 549 23 genes were differentially expressed between prepubertal vs adult bovine gv and mii stages oocytes respectively of these 176 and 312 genes were upregulated while 157 and 237 were downregulated in prepubertal when compared with adult gv and mii oocytes respectively it was also observed that 695 29 and 553 23 genes were differentially expressed between gv vs mii stage oocytes in the adult and prepubertal groups respectively gene ontological classification of the differentially expressed genes revealed that upregulated genes in adult oocytes were involved in signal transduction transcriptional control and transport quantitative reverse transcriptionpcr validated the expression profile of some selected transcripts and confirmed differences in the expression levels of transcripts between adult vs prepubertal groups in both gv and mii stages oocytes as identified by microarray data analysis this study indicated for the first time that significant number of genes were differentially expressed 2fold p 001 between oocytes derived from adult and those from prepubertal japanese black cattle and this difference increased during ivm