Integrating biobanking minimises inbreeding and produces significant cost benefits for a threatened frog captive breeding programme

Abstract

Captive breeding is an integral part of global conservation efforts despite high costs and adverse genetic effects associated with unavoidably small population sizes. Supplementing captive-bred populations with biobanked founder sperm to restore genetic diversity offers a solution to colony size, costs and inbreeding, yet is rarely done, partly due to a lack of concrete examples or awareness amongst the conservation community of the huge potential benefits. We present a model system of the cost and genetic benefits achieved by incorporating biobanking into captive breeding of Oregon spotted frogs (Rana pretiosa). Backcrossing with frozen sperm every generation resulted in very large reductions in required programme expenditure compared to traditional captive breeding. This model supports the view that integration of biobanking into captive breeding would make longstanding and previously unachievable genetic diversity retention targets feasible (90% source population heterozygosity for a minimum of 100 years) at much reduced costs. This study suggests that the credibility of captive breeding as a conservation strategy would be enhanced by integrating genome storage and assisted breeding to produce far larger numbers of animals of higher genetic quality. This innovation would justify increased public and agency support for captive breeding.