Natural Born Mutants

Although direct engineering of animal and plant genomes only became possible from the 1970s onwards, people have been indirectly changing other species’ genetic make-up for thousands of years. This is because with the agricultural revolution that began 12,000 years ago, human beings began selecting particular variants of a species, and cultivating them as crops or breeding them as farm animals, and in the process altered a species’ genome over time. In fact this process began even earlier, with the domestication of the wolf, which eventually became our most faithful companion, the dog. And now modern genome analysis techniques are making it possible to understand how at the genetic level a dog or cat differs from their wild ancestors, or how wild boars became pigs, or wild grass could over time give rise to wheat, barley, or rice. In medical research, scientists realised that understanding how genes work could be helped by studying naturally occurring mutants. By studying how mutations affected an organism such as a fruit fly,genes involved in particular functions could be identified. A breakthrough was made when it was realised that treatment of fruit flies with X-rays dramatically increased the numbers of mutants. Today, X-rays and chemical treatments can be used to create mutant mice, and studies of such mice has identified genetic links with conditions such as congenital deafness.