WEEK-10-Polyploidy and Xenogenesis
Polyploid Induction in Fish
Triploidy is induced by allowing normal fertilization and then forcing retention of the second polar body (Chourrout, 1980, 1984; Lou and Purdom, 1984). The second polar body is retained by applying temperature (hot or cold), hydrostatic pressure, anaesthetics or chemical shocks shortly after fertilization (Thorgaard et al., 1981;
Wolters et al., 1981a; Chourrout and Itskovich, 1983; Benfey and Sutterlin, 1984a;
Chourrout, 1984; Cassani and Caton, 1986a; Curtis et al., 1987; Johnstone et al., 1989).
Xenogenesis
A xenogenic organism is comprised of elements typically foreign to its species.
Xenogenesis is a method of reproduction in which successive generations differ from each other.
Xenogenesis has been accomplished in fish using stem cells from testicular tissue.
Testes contain six major types of cell: primordial germ cells (PGCs), spermatogonia A, committed spermatogonia B, spermatids, mature sperm cells and somatic cells.
