Propagation of the Sperm Genome

Among infertile men the degree of spermatogenesis varies from a barely compromised sperm number in the ejaculate to complete absence-the condition known as azoospermia. The scarcity of gametes often represents a major hindrance to overcoming spermatogenic failure through the use of assisted fertilization techniques. Therefore, we attempted to replicate the fertilizing spermatozoon by ‘male genome cloning’ in order to empower an individual spermatozoon. Spermatozoa injected into mature ooplasts were capable of maintaining and replicating a haploid male genome as haploid androgenotes. Isolated nuclei from such androgenotes entered into syngamy with female PNs following nuclear transfer fertilization. By utilizing mouse 8-cell stage androgenotes, we were able to obtain 6 blastocysts per single spermatozoon, and consequently live offspring. Thus, we were able to enhance the reproductive performance of single spermatozoa, indicating a possible future application of male gamete genome profiling prior to fertilization.