The Gynogenesis and Androgenesis of the Diploid Gametes Derived from the Allotetraploid Fish

Artificial gynogenesis is a good approach to improve the fish germplasm. Generally, in this approach, eggs are stimulated by genetically inactivated sperm (generally, sperm from different species are used), and the chromosomes in eggs are doubled which results in offspring containing maternal genetic material. In this process, the haploid eggs undergo a treatment for doubling the chromosomes, which possibly damage the "fertilized" eggs and will reduce the survival rate of the gynogenetic progeny. By using diploid eggs from tetraploid fish, the doubling chromosome procedure is unnecessary which simplifies the operation process and improves the survival rate of gynogenetic progeny. Besides gynogenesis, diploid gametes could be used to improve androgenesis approach. Artificial androgenesis is the fertilization of genetically inactivated eggs with normal sperm. During common induced process of androgenesis, the chromosomes from sperm nuclei need to be doubled. On the contrary, using diploid sperm from tetraploid fish, the chromosome doubled process is unnecessary to obtain diploid androgenetic progeny. In our previous studies, the allotetraploid lineage of red crucian carp (Carassius auratus red var., RCC, ♀) × common carp (Cyprinus carpio L., CC, ♂) has been established and lasted for 27 generations (F3–F29). Both the female and male individuals produced stable diploid eggs and sperm. This chapter introduces gynogenesis and androgenesis using diploid gametes derived from allotetraploids of red crucian carp × common carp (4nAT).