Bad breeding

 作者:熊淬攥     |      日期:2019-03-07 07:05:12
PARASITES are good for a species because they promote genetic variability in their hosts. Now a study of sheep in Scotland suggests why (Evolution, vol 53, p 1259). David Coltman’s team at the University of Edinburgh found that inbred sheep have worse nematode infestations, and are more likely to die than less inbred sheep. But if sheep are purged of worms,