How is genetic taken into account in captive breeding program? Asan Hilal Dubois Anne-Cécile

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1 How is genetic taken into account in captive breeding program? Asan Hilal Dubois Anne-Cécile

2 Content What is captive breeding? Disadvantages of captive breeding Genetic as a solution? How genetic is used? Disadvantages of genetic in captive breeding programs Conclusion: is captive breeding a good tool for conservation?

3 What is captive breeding? Breeding animals in human controled environments with restricted settings Release to the wild, when sufficient natural habitat, to support new individuals the threat to the species in the wild is reduced Rosa2003release jpg Goal = conservation to prevent extinction of species

4 What is captive breeding? Need of knowledges about biology, ecology Carefull analyses conservation status exact nature of the problem

5 Successful captive breeding? Depends on the maintain of Effective population size : sex ratio variance in family size fluctuation in population size High proportion of the genetic diversity Loss of heterozygosity Frequency of allele changes Presence of lethal allelism Presence linkage disequilibrium bubblepanda.hubpages.com

6 Successful captive breeding? At the end 90% of the wild genetic diversity should be saved : captive population large enough sufficient number of founders at the basis of the captive breeding population pair combinaisons carefully managed : methods of «minimising kinship»

7 Roles of the captive breeding program Provide an insurance against extinction Stock for reintroduction or reinforcement efforts Opportunities for education, raising awareness Scientifics research

8 Example of an efficient captive breeding program : Arabian Oryx Arabian Oryx Oryx leucoryx In the 20th century, high hunting pressure: In 1960s important decreased of population (only about individuals) In 1962: expedition to securise the stock of Oryx Last wild individual shot in 1972 : extinct from the wild phoenixzoo.org

9 Example of an efficient captive breeding program : Arabian Oryx Very efficient captive breeding program set up: in 1982 first flock reintroduced in the wild (in Jiddat al Harasis desert) Other release in and In 1990 : 109 oryx 2011 : about individuals in the wild. Now vulnerable (IUCN)

10 Disadvantages of captive breeding Do not learn how to face wild life Inbreeding => decreased genetic flow canadianpoultrymag.com

11 How genetic can be used in captive breeding programs? Use of nuclear and mitochondrial markers (Tzika et al 2008) Use of pedigree info (Goyache et al 2002) Examples of how to improve genetic methods in conservation

12 Use of nuclear and mitochondrial markers Example: Endemic Jamaican Boa Endangered, due to introduced species, human persecution and habitat destruction. Goal: Founder s natural population Identify parental allocation errors Estimate genetic diversity and Inbreeding

13 Level of Inbreeding Loss of alleles, reproductive success, relatedness among individuals. Measures of relatedness derived from genotypes with parameters: - Age of animals - Localization of host insitutes Mating groups to maximize genetic diversity

14 Result More efficient breeding program Increased probability of long-term survival.

15 Captive Breeding Program 7 wild-born individuals transferred from Hope Zoo to Europe. Later 4 more. 600 offspring produced in 30 years. Pedigree information was added. (data available on: Questioning institutions and individual house founders Problems: Unknown exact genetic relatedness of founders No accurate record keeping Unusual mating behavior (2 males and 1 female)

16 Goal Use nuclear and mitochondrial markers Assess genetic diversity Assign parents to each offspring Compute reproductive success of each individual Estimate the effective population size Mating groups to maximize diversity

17 Parental allocation and Genetic Variability Parental allocation: Using nuclear markers, identify parents based on individual genotypes also missing parents can be detected if a part of them are absent. Relatedness estimation: Across all loci for each possible female x male pair. 1: genetically identical 0 : distance = E (comparing two random pair)

18 Methods Partition individuals into three categories: -> Founder (F0) -> The First Generation (F1) -> The Second Generation (F2) And find, variations, allelic richness, heterozygosity. Observed heterozygosities Expected heterozygosities Mean allelic richness Significant differences in 3 categories above? Allelic Richness was significantly different between F0 and F2

19 Methods Estimation of relatedness allows us to design mating groups so that the diversity is maximized. Other parameters: Age, localization of the institution, mating behavior (3 individuals).

20 Use of Pedigree Information Example: Endangered Xalda sheep breed of Asturias Set parameters to characterize -> structure of populations and management practices. Problem: 805 animals -> herds -> 26 Risk of losing genetic diversity

21 Problems The effective number of founder animals is 81.1, herds is 9.9. The average value of inbreeding, 1.5%. The average relatedness coefficient, 1.8% Unbalanced line of founders The risk of loss of diversity needs to be assessed in detail.

22 Solution Monitoring of the breed using AR Balance the line of founders Introduce new animals with low AR

23 Problems The rate of inbreeding, in which cases can be misleading? - Quality of the avaliable pedigree info, Incomplete pedigrees - Actual domestic animals do not remain closed for a long time

24 Proposed Techniques, Attributes The effective number of founders (Lacy, 1989,1995) The founder genome equivalents The effective number of ancestors (Boichard et al., 1997) Equalizing founder contributions (Alderson, 1991) Unbalance offspring (Ballou and Lacy, 1995)

25 The average relatedness Ensure the minimum increase in inbreeding Genetic variability depends on? - The size of the base population Solution: Use AR to balance the line of founders. Can t only consider inbreeding Consider also, - Structure.

26 The average relatedness Inbreeding is not the best indicator! Predicts long term inbreeding, Suggests modifications to management practices % of the complete pedigree originating from a founder % of a genetic contribution of a line of founders

27 Disadvantages of the genetic in captive breeding programs Accelerate rate of genetic drift in potentially small broodstocks. Alleles beneficial in captivity but deleterious in wild => Loss of wild type alleles Enhance likelihood of accumulation of deleterious alleles Gene flow intentional : increase wild population size. BUT Gene flow inadvertent : HARMFUL to fitness

28 Disadvantages of the genetic in captive breeding programs Natural populations not any longer capable to sustain themselves

29 Conclusion It can be very efficient or harmful, depending on the populations, the species, how genetic flow can be controled etc. Still need to work on the preservation of habitat, for a more sustainable conservation, whith effect on different species.

30 References Captive breeeding program - a usefull tool in the preservation of biology? by Carsten Rahbek February 1993 Captive breeding and the genetic fitness of natural populations by Michael Lynch and Martin O Hely; March 2001 Maintenance of genetic diversity of Atlantic salmon (Salmo salar) by captive breeding programmes and the geographic distribution of microsatellite variation by Marja-Liisa Koljonen, Jaana Tähtinen, Marjatta Säisä, Jarmo Koskiniemi ; Septembre 2002 Using pedigree information to monitor genetic variability of endangered populations: the Xalda sheep breed of Asturias as an example, by F. Goyache, J. P. Gutiérrez, I. Fernández, E. Gomez, I. Alvarez, J. Díez, L. J. Royo; March 2003 Molecular genetic analysis of a captive-breeding program: the vulnerable endemic Jamaican yellow boa, by Athanasia C. Tzika, Christophe Remy, Richard Gibson and Michel C. Milinkovitch Captive breeding and conservation by Kristin Leus; 2011