Sir

In his review of Tim Birkhead's entertaining book The Red Canary (Nature 425, 772; 2003), Jerry Coyne disputes the relevance of ‘genetically engineering’ red canaries (by crossing the birds with the South American red siskin and feeding them carotenoids) to the modern debate on transgenics. In my view, the current controversy surrounding the commercialization of GloFish, a fluorescent zebrafish with sea anemone genes (Nature 426, 372 and 596; 200310.1038/426372b), could gain a useful perspective from the story of the red canary.

GloFish continues the historic tradition of genetic modification of pets that has resulted in such oddballs as peculiarly shaped dogs, hairless cats and coloured birds. The red canary is remarkable in that the red-factor gene was bred into the canary genome from a distinct species, and therefore does not differ in principle from GloFish. Members of the California Fish and Game commission, who voted against the sale of GloFish in the state and concluded that “aesthetic reasons are not sufficient justification for the genetic modification of animals”, should probably endeavour to ban the sale of red canaries and other hybrid pets.