Animal Research : Case study

Research using fruit flies has several major advantages over using mammals:

  • It is widely considered ethically more acceptable
  • It is far cheaper
  • It is far quicker
  • There are some very sophisticated techniques in flies that cannot be done in mammals

However, it has one major limitation: it is much further removed from humans than studies in a mammal. Nevertheless, by collaborating with leading US fly geneticists, we were able to take a major step towards understanding nerve degeneration in mammals, including humans, while reducing the number of mice needed to identify a new drug target by as much as a thousand-fold.
A large screening programme in flies was able to identify mutations that delay nerve degeneration. Further flies were needed to rigorously confirm that the right gene had been identified but up to this point no other animals were used. To confirm that the results are relevant to mammals, we first used cultured neurons from healthy mice that lack the same gene and found that these too showed resistance to degeneration. Only then were studies carried out in a few live mice for a final validation in a living mammal. We know that humans have the same gene. Partly as a result of this work, it has now been associated with motor neuron disease and has become an important drug target for neurodegenerative disorders. 
It is questionable whether this gene could ever have been found by studying mice directly. It would also have been extremely difficult to fund this work in mice and it would have taken far longer to complete. Thus, this is a welcome development for patients and taxpayers alike, and an excellent example of how the search for alternatives can sometimes lead to even better science. However, the results must be validated in a mammal.