Gynogenesis (gyno = female)

A competent adult can be derived from oocytes without fertilisation by sperm.

1) A haploid (one set chromosomes) oocyte (unfertilised egg) is activated (triggered to divide) by pricking.

2) During the first division cytokinensis (the splitting of the egg into two cells after the duplication of the nuclei) is prevented by temperature shock (the raising or lowering of temperature for a short period).

3) This cell grows into a normal diploid animal (fish or frog).

Limitations

1) Gynogenesis can only produce female animals. However, genetic diversity may be re-established in subsequent generations by fertilisation with genetically diverse sperm.