Principles of Genetics and Breeding

4.1.5 Parthenogenesis

• Parthenogenesis in a broad sense to mean all modes of reproduction in which one or more genomes are inherited clonally.

• All of the parthenogenetic fishes require the physical stimulus of sperm to induce embryogenesis. Thus, all parthenogentic fishes must mate with males of closely related sexual species to achieve reproduction.

• This fact has a profound effect on their population biology, since those partheno species must coexist with closely related sexual species and must succeed in reducing males of sexual species.

• Gynogenetic species produce eggs with chromosome numbers identical to those of the somatic cells; sperms merely stimulate development and male chromatin is never expressed in the progeny. The important genetic consequence of gynogenesis is that daughters are genetic replicates of their mothers. This type of reproduction was reported in Poeciliid fishes.