Genetic manipulation in higher organisms. I. Goldfish ova as materials of operation, mRNA mediated alteration of the liver specific isozymes.

Both crucian and carp egg-mRNAs were found to mediate the transformation of goldfish tail from the double (veil-shaped) to the single (fork-shaped). Livers of these single tailed goldfish were tested for genetic change using lactate dehydrogenase isozymes (LDH) as marker. Electrophoresis of liver extracts on starch gel showed that the liver specific LDH-C4 isozymes of both the egg-mRNA and liver-mRNA injected goldfish resembled the control goldfish except an additional intermediate band. The migration distance of this new band matched the third band of the hybrids (carp X goldfish). These findings lead to the conclusion that carp egg-mRNA contains a fraction partly responsible for liver development. Rat liver was found possessing the cathodally migrating C4 isozymes. Injection of rat liver-mRNA into goldfish eggs resulted in the intensification of the liver specific C4 isozymes. It appears therefore that the input informational molecules (liver-mRNA) and the output molecular products (liver C4 isozymes) are causally related. This causal relationship would pave the way for genetic manipulation in higher organisms.