A central premise in conservation genetics is that high genetic diversity is good for a species’ continued survival, and low genetic diversity is bad. This seems intuitively obvious (after all, we all know that you shouldn’t marry your cousin) but actually finding examples in nature where we can say for sure that low genetic diversity has contributed to a population’s demise is difficult.
However, the recent decline of tasmanian devil populations due to disease provides an excellent example of the perils of low genetic diversity. Wild devil populations in eastern Tasmania have been decimated in recent years by devil facial tumour disease (DFTD). This nasty disease is a transmissible cancer spread by biting, and causes large tumours to form around the mouth, interferring with feeding and eventually causing death. Kathy Belov’s group at the University of Sydney has been studying the genetic basis of DFTD susceptibility in devils and has found that a lack of variation in immune system genes is responsible for the spread of the cancer in some populations. Read the rest of this entry »