Poor development of human nuclear transfer embryos using failed fertilized oocytes.

Failed fertilized human oocytes from IVF were enucleated and used as recipients for somatic cell nuclear transfer. The reconstructed embryos frequently formed an expanded nucleus from the injected genome after activation. However, subsequent development beyond the 1-cell stage was poor, and the resulting embryos showed chromosomal abnormalities. Poor development of oocytes after nuclear transfer contrasted with that of control, sperm-injected oocytes, which often progressed to cleavage stages. These results suggest that failed fertilized oocytes are not effective recipients for somatic cell nuclear transfer.