Development of artificial gametes.

Virtually all normal cells can reproduce themselves. The germ cells, however, can initiate reproduction of the entire organism. A special sequence of events, meiosis, is responsible for generating mature germ cells bearing a haploid genome. The basic features of meiosis, i.e. two cell divisions with no intervening DNA replication, resulting in a halving of the chromosome complement, are evident throughout evolution. The idea of generating an artificial gamete was recently put forward to provide an ultimate solution for the treatment of infertility. Currently, there are different strategies to create artificial gametes in vitro, such as converting somatic cells from mitotic division to meiotic division directly (somatic cell haploidization), or dedifferentiating somatic cells into embryonic stem (ES) cells and re-differentiating ES cells into gametes, or extracting adult stem cells and re-differentiating them into gametes.