Breeding Disease Resistant Frogs

Captive breeding is important in the efforts to protect frog populations from chytrid fungus but selective breeding often brings out other health issues. Caution

Captive breeding of frog species threatened by chytrid fungus disease is the work of the Amphibian Ark project. By isolating populations of healthy frogs in special units around the world it is hoped that, once a method of dealing with the deadly fungus is developed, the unaffected frogs can be returned to the wild.

One of the areas of study has been into levels of resistance to the disease in various frogs. A recent paper shows that Major Histocompatibility Complex (MHC) plays a role in that resistance. The suggestion is made that captive breeding for this resistance might be the answer to the dilemma.

But the study also noted that the frogs which survived the experimental infection with a common bacterial pathogen often grew more slowly than their siblings who didn’t show the disease resistance. This is an important point. It is not unusual in genetics for a ‘good gene’(one that produces a desired quality) to be paired with a ‘bad gene’ (one that produces undesirable qualities).

So the results of the study need to be kept in perspective. Captive breeding programs need to use this new knowledge in conjunction with the awareness of other genetic qualities needed to ensure long-term survival of endangered frog species. The health problems of carefully bred domestic animals are a constant reminder of that.