Alternative cell sources for cryobanking in fish

1 Cryopreservation of somatic ceHs and chaUenges of nudear transfer technology 

When gametes and embryos are not easily available, somatic cells should be considered for fish genome cryobanking. Although especially valuable 

6 Pluripotent cell cryopceservation and reconstruction with blastomeres versus embryonic stem cells 

Pluripotent cells are embryonic or embryonic-derived cells with the ability to differentiate into multiple cell types. Initially, pluripotent cells are blastomeres obtained from early stage embryos. They are then either directly cryopreserved and used for reconstruction, or cultured in conditions which will enable them to maintain pluripotency, together with their self-renewal potential. Such cultured cells are referred to as embryonic stem cells (ES cells). 

Once thawed, blastomeres cells can be transplanted into a recipient embryo, leading to the formation of a chimera. The purpose of such transplantation is so injected cells contribute to formation of the germline. Chimera production with cryopreserved cells has been successfully reported in rainbow trout (Takeuchi et al, 2001,2004), together with successful germline transmission, although transmission rates were very low. Germline transmission rates were improved after the recipient cells were weakened by irradiation (Joly et al, 1999). In zebrafish, only two adult chimaeric specimens were obtained from a total of 47 injected embryos 

---