GENTECH archive


Extinction Genie (1)

Researchers found that an aquarium fish, Japanese medaka (Oryzias latipes),
modified with a growth gene hGH were more succesful in attracting mates.
This meant that the gene spread rapidly through the population. However
only two thirds of the modified medaka survived to reproductive age
compared with wild medakas.

The spread of the growth hormone gene could therefore make populations
dwindle and eventually become extinct.

Using a computer model they discovered that releasing 60 modified fish into
a wild population of 60,000 resulted in extinction in just 40 generations.
Release of even a single modified fish could also result in extinction,
though over a longer period.

The work appears to be applicable to salmon who have similar mating
The researchers are hoping to test their predictions in tightly controlled
fish farm ponds.

I think this highlights the fact that what appear to be beneficial
modifications can have unfortunate results. Once the genetic genie is
released there is no way to put it back.

[Proceedings of the National Academy of Sciences (vol 96, p 13 853)]