DELAYED IN-VITRO FERTILIZATION OF ZEBRAFISH EGGS IN HANKS SALINE CONTAINING BOVINE SERUM-ALBUMIN

in zebrafish it is possible to create viable diploid fish whose genomi c DNA is derived only from the female parent (parthenogenesis) or, as was more recently shown, only from tile male (androgenesis). Androgene sis requires holding zebrafish eggs in an inactivated state in vitro f or an hour or more. Previously this was achieved by placing the zebraf ish eggs in ovary fluid obtained from rainbow trout (Onchorhynchus myk iss) or coho salmon (Onchorhynchus kisutch). Here we report that addin g bovine serum albumin (BSA) to Hank's buffered saline prevents zebraf ish egg activation in vitro. Of the zebrafish eggs placed in Hank's sa line plus 0.5% BSA, 85% +/- 8.7% were fertilizable after incubation fo r one hour at room temperature (23 degrees C). Longer incubations are possible but with lower efficiency of fertilization. This technique no t only could facilitate androgenesis, but also might be useful when ma king transgenics by microinjection, when performing antibody or RNA in jections before fertilization, or for studying the mechanisms of egg a ctivation in zebrafish.