The importance of genetic analysis in developing protocols for pilot scaleintroductions of captive-bred Margaritifera margaritifera into the wild

Transcription

1 The importance of genetic analysis in developing protocols for pilot scaleintroductions of captive-bred Margaritifera margaritifera into the wild ConorD. Wilson, Caroline R. Bradley, Hazel C. Clarke, Dai Roberts, S. Jane Preston & Jim Provan Quercus, Queens University Belfast

2 Outline Captive breeding -a short review What is captive breeding and why use it? Why is genetic analysis important in endangered species biology? Genetic analysis of M. margaritiferain Northern Ireland Introduction Materials and Methods Results Conservation implications

3 Captive breeding Definition -A means to conserve a species that is incapable of surviving in the wild Main aim was once to increase numbers and keep in a secure place More modern approach is to manage in a way so as to maintain high genetic diversity and avoid or minimize inbreeding However, captive breeding should be considered a last resort or stop gap, and will never resolve the deep-rooted underlying issues that most endangered species face need a multidisciplinary approach

4 Why use captive breeding? Insurance against extinction in the wild Increase animal numbers for release CAPTIVE BREEDING Maintain or maximize genetic health Secure ex-situ locations Educate and engage Provide focus for fundraising Provide animals for research on basic biology

5 Some successful examples American Bison Hunted from >40 million to 500 Now number through captive breeding Black footed ferret Declined through habitat loss, decline in prey numbers and disease Captive breeding programme used 18 founders Now 250 captive adults, genetic management is employed to reduce kinship Now 1200 animals in the wild

6 Disadvantages of captive breeding Costly May be seen as a quick fix Need experienced animal husbandry CAPTIVE BREEDING Need a secure location Need to investigate gene pools of captive and wild populations

7 A genetic approach to endangered species management Molecular genetics can help us make informed decisions about wild and captive population management Main aim is to preserve/maintain/maximize the genetic diversity of the captive population as much as possible A genetic management approach will help identify and counteract deleterious genetic changes e.g., accumulation of genetic mutations, adaptation to captivity, inbreeding depression, loss of genetic variation and outbreeding depression. And help identify conservation units in the wild

8 The importance of selecting founders Founders are often presumed to be representative of wild populations, however, this if often not the case and investigation is necessary Example, Asiatic Lion captive breeding programme. Founders identified as African Lions after genetic analysis project abandoned, a lot of money wasted! It is through establishing small or poorly selected founders that a reduction of genetic fitness of subsequent offspring occurs, called a Founder Effect. A Founder Effect leads to a population bottleneck and increased inbreeding

9 Population bottleneck and inbreeding Population bottleneck A phenomenon that occurs when the size of a population is greatly reduced Leads to a reduction in genetic diversity Adaptive potential of population is greatly reduced Inbreeding depression Occurs when closely related individuals reproduce Leads to a reduction in genetic diversity Adaptive potential of population is greatly reduced

10 Importance of genetic analysis of wild populations Need to identify unique populations and those with high levels of genetic diversity, i.e. evolutionary significant units or conservation units This will help highlight the need to preserve the adaptive variance within the species Help avoid outbreeding depression - the deleterious consequences from crossing genetically differentiated populations Example, Selection in one population might produce a large body size, whereas in another population small body size might be more advantageous. Gene flow between these populations may lead to individuals with intermediate body sizes, which may not be adaptive in either population.

11 Aims and objectives of study Aim Compare the gene pools of wild, captive and cultivated M. margaritifera populations Objectives, determine whether: the captive brood stock population has the same genetic diversity as the river population the captive brood stock population is representative of wild populations in the rest of Northern Ireland the cultivated populations are representative of the broodstock

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