Inbreeding is commonly regarded as detrimental and is of growing concern for wild populations that are increasingly fragmented and isolated by habitat loss. John Hogg at the Montana Conservation Science Institute in Missoula and colleagues found that outbreeding - introducing new animals - could help revitalize an inbred pocket of bighorn sheep, in a natural setting.
The researchers followed a population of bighorn sheep isolated to an average size of 42 animals for about 11 generations. After outbreeding efforts began in 1985, scientists detected marked improvements in reproduction, survival, and five other traits related to fitness, such as offspring birth weight, among the descendants of 15 recent migrants.
"It shows the practical importance of gene flow from the outside even in species like bighorn sheep, which tends to be found in habitat patches that are somewhat isolated due to their population structure," says Faculty of 1000...