Detection of human novel developmental genes in cDNA derived from replicate individual preimplantation embryos.

We have constructed amplified cDNA preparations from replicate samples of human oocytes and individual preimplantation embryos. Differential display of the cDNA preparations shows disparate patterns of gene expression in the individual embryos at all stages of preimplantation development. The variation in patterns of genes expressed is in part due to the low starting cell number undergoing the reverse transcription-polymerase chain reaction (RT-PCR) step in the preparation of the amplified cDNAs. Despite this variability, the use of replicate embryo samples makes it possible to identify and isolate human genes specifically expressed at the different stages of human preimplantation development from the unfertilized oocyte to the blastocyst stage.