Transcript 11 Conservation Genetics the use and importance of genetic

Conservation Genetics
the use and importance of genetic information
鄭先祐(Ayo)
國立台南大學 環境與生態學院 教授
[email protected]
Contents
Genetic variation: what is it and why is it important?
Forces that affect genetic variation within populations
Using conservation genetics to inform management
Identifying and prioritizing groups for conservation
Genetic information and design and implementation of
breeding strategies
 Forensics and species or population identification
 Understanding effects of population exploitation on
levels of genetic diversity
 Limitations of using genetics in conservation planning
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Supplements
 Box 11.1 measures of genetic
diversity
 Box 11.2 estimation of effective
population size
 Box 11.3 calculation of F-statistics
 Essay 11.1 co-adaptation, local
adaptation, and out-breeding
depression
 Essay 11.2 a rose is a rose is a rose
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Supplements
 Case study 11.1 genetics and
demography of grizzly bear
populations
 Case study 11.2 using genetic
analyses to guide management of
Pacific salmonids
 Case study 11.3 Scat-singing the
wildlife conservation blues.
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Introduction
 Contemporary extinction rates are as
high as any that have ever occurred
on Earth.
 When a population or species
disappears, all of the genetic
information carried by that population
or species is lost.
 Gene pools are becoming diminished
and fragmented into gene puddles.
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Genetic issues in conservation biology
1. inbreeding depression
2. Loss of genetic diversity and ability to
evolve in response to environmental
change
3. Fragmentation of populations and reduction
in gene flow
4. Genetic drift
5. Genetic adaptation to captivity and its
adverse effects on reintroduction success
6. Resolving taxonomic uncertainties
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8. Defining management units within species
9. Use of genetic analyses in forensics(驗明正身)
10.Use of molecular genetic analyses to
understand aspects of species biology.
11.Deleterious effects of fitness that
sometimes occur as a result of outcrossing (outbreeding depression)
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Using conservation genetics to
inform management
 Allow continued evolutionary change.
 Ecological systems are dynamic and
generally are not at equilibrium.
 The best way to manage such
dynamic, changing systems is to
permit and allow for change.
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Time scales of concern
1. Maintenance of viable population in
the short term (extinction avoidance)
2. Maintenance of the ability to continue
adaptive evolutionary change,
3. Maintenance of the capacity for
continued speciation
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Identifying and prioritizing groups
for conservation
1. Conserve basal taxa
2. Conserve species-rich groups
3. Conserve species that are most
different from one another
4. Conserve those taxa maximize
phylogenetic diversity (PD)
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Genetic information and design and
implementation of breeding strategies
 Use of pedigrees (系譜)：
 Pedigree analysis represents the genetic study
of multigenerational population with ancestral
linkages that are known.
 Use of pedigrees is typically restricted to
relatively small captive populations (zoos,
domestic, or companion animals)
 Estimation of degree of relatedness without
knowledge of pedigree relationships
 Polymorphic loci analysis
 Genetic markers
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Forensics (驗明正身)
 Molecular genetics has been used for
forensic identification of commercial
products from endangered species.
 Products including ivory, horn, shell,
meat, feathers, dried leaves and a host
of other commercially valuable items
that are derived from plant or animal
materials.
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Individual identification and
estimation of population size
 Small quantities of DNA can be
routinely collected noninvasively
using hairs, feathers, feces, and even
sloughed skin.
 Reviews of technology and empirical
applications are provided in Cornuet et al.
(1999), Mills et al. (2000), and Palsboll
(1999).
 如此可以 identify individuals, 運用markrecapture 估計族群的數量與變動。
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Fig. 11.13 Forensic identification using mtDNS of “dolphin or minke
whale meat” samples legally sold in Japanese markets. All bold faced
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specimens were from whale species that have not been legally
harvestable since 1976.
Understanding effects of population
exploitation on levels of genetic diversity
 Many species are subjected to sport
or commercial harvest.
 Exploitation changes population size,
sex ratio, and age structure that can
have effects on genetic diversity.
 Male-only harvest of deer and the
resulting sex ratio skew in favor of
females in populations of mule deer.
 Commercially exploitation of Pacific
salmon
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Limitations of using genetics in
conservation planning
 The fields of evolutionary biology, and
population and molecular genetics, which
are the foundations of conservation
genetics, are well established.
 Genetic technology does have limitations
however, and will not alone be the savior of
biodiversity.
 Habitat availability and biological
interactions and processes should be the
primary focus of conservation every where.
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 Without suitable ecosystems and
dynamic ecological processes, high
levels of genetic diversity alone would
not ensure long-term population
viability.
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Supplements
 Case study 11.1 genetics and
demography of grizzly bear
populations
 Case study 11.2 using genetic
analyses to guide management of
Pacific salmonids
 Case study 11.3 Scat-singing the
wildlife conservation blues.
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問題與討論
http://mail.nutn.edu.tw/~hycheng/
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