Lecture 12 - Conservation Genetics Flashcards Preview

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Flashcards in Lecture 12 - Conservation Genetics Deck (29)
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1

What are the two main issues in conservation biology?

Population genetic principles
Genetic methods

2

What are the population genetic principles as an issue in conservation biology?

-Small and fragmented populations
-genetics of a small population

3

What are the genetic methods as an issue in conservation biology?

Parentage and kinship
Species identification and forensics
Evolutionary significant units
Hybridisation
Species phylogeny
Species cloning/reconstruction

4

What methods can be used to assess migration rates across a barrier to dispersal (geographical)

-Radio telemetry (e.g. Ventura freeway near LA which dissects wildlife habitats, different methods were used to dissect the impact of genetics on the population e.g. Migration across the freeway; 1.3% coyotes per generation, 3.3%bobcats per generation)
-Assignment tests
-Estimates from Fst data

5

What are assignment tests?

Use genetic data to assign individuals to genetic clusters without the need for knowledge of where the individual came from
-this can then be matched with knowledge of the populations in question
-mostly done with bayesian algorithms
(e.g. Assignment of coyote population
Significant num of migrants but estimates from the Fst were 3-18 times lower than genetic estimates meaning that migrants generally fail to reproduce. Corridors could be used to reduce impact)

6

What would you assume if migration rates from Fst data estimates were much lower than direct estimates (from assignment tests)?

That migrants generally fail to reproduce
-can use corridors to reduce impact

7

What potential problems are there with populations in zoos?

-Zoos relatively stress free environment
-release into the wild might uncover inbreeding effects
E.g. Inbreeding depression exposure is related to stress
E.g. Sabbatical angularis shows more decreased fitness due to inbreeding depression in the field than in the greenhouse

8

How can inbreeding in small captive populations be minimised?

Minimise inbreeding using pedigrees
-inbreeding in small captive populations can be delayed but not avoided

9

Outline genetic rescue with regards to Swedish adders

-Costal strip 1km X 0.1 km isolated from other adders for over 100 years
-high proportion of deformed and still born offspring and low genetic variation
-twenty adult males introduced from large, genetically variable population
-led to genetic rescue, more recruit and total population increased over time and genetic variation after the introduction increased

10

Outline genetic rescue with regards to the florida panther

-isolated form other panther populations for over 100 years
-low genetic diversity, cow licks, kinked tails, poor semen quality, heart defects
-90% of males born after 1990 had one or both testes undescended

11

Outline genetic rescue in regards to Wolves

-Wolves from Norway
-Founded natually from a single pair in early 1980s
-third individual arrived in 1991
-Regression lines less steep after the arrival of the third individual

12

Give an examples of when a small population does not show genetic depletion

•Indian rhino
•Isolated population in Chitwan, Nepal
•In 1962 reduced to ca. 70 rhinos
•Now ca. 400 rhinos
•Rare alleles maintained, possibly because of quick recovery

13

Give an example of when species with genetic depletion do NOT die out

•Northern elephant seal
•< 20 Individuals in 1890s
> 200,000 now
•but very little detectable genetic detectable variation

14

What summaries can be reached from extreme population reductions from the examples?

•If extreme population reductions are halted and reversed quickly, may lose little genetic variation
(e.g. Indian rhino)
•Even if genetic variation is lost, population may recover (but long-term future uncertain)
(e.g. Northern elephant seal, Scandinavian wolf)
•May be disastrous, severe inbreeding depression and loss of genetic variation (reversible with genetic rescue)
(e.g. Florida panther, Adder)
•Small differences in life history can have a substantial impact on the outcome
(Australian geckos, different dispersal patterns)

15

Outline an example of how small differences in life history can have a substantial impact on the outcome of extreme population reductions

Australian Gecko
•Different dispersal pattern
•G. variegate (good at dispersal), but not O. reticulate (bad at dispersal): Isolation by distance

16

Outline the Glanville fritillary as an example of inbreeding and extinction

Inbreeding and extinction: the Glanville fritillary

•1600 suitable dry meadows
•~ 200 extinctions > 114 colonisations/year
•Screened 42 populations at 8 loci (Allozymes and microsatellites)
•Populations with less genetic variation were more likely to go extinct
•Egg hatching rate and larval survival lowest in these populations

17

What was observed about Wolves bred in captivity? (Inbreeding)

Litter size, weight, longevity, and female reproduction rates are reduced by 6-7% per 10% increase in inbreeding
-Heredity blindness is associated with inbreeding (Laikre and Ryman, Laikre)

18

What was observed about Brown bears bred in captivity? (Inbreeding)

Litter size decreases 6.3% with 10% increase in inbreeding
-albinism is associated with inbreeding (Laikre, Andren)

19

What was observed about Lynx's bred in captivity?

Longevity decreases with increased level of inbreeding
-(Lundstrom, Laikre)

20

How can inbreeding be avoided?

Establishing parentage in founder populations
Micronesian kingfisher
•extinct in the wild due to predation by snakes
•29 taken into captivity to start breeding programmes
•Parentage established to avoid inbreeding

21

What technique can be used to test whether captive individuals are the result of breeding programmes?

DNA fingerprinting e.g. Peregrine falcons

22

How was forensics used to analyse the Japenese and Korean markets of whale/horse meat?

Identifying Horse meat vs. Whale meat
Japenese markets
-700 whale products analysed 1993 – 1999
-Much of it illegal: Fin, Sei, Brydes, Blue fin hybrid and grey are all protected, but account for 10% of whale products on the market
-Asian gray (protected since 1937) and Asian humpback (protected since 1966) not recovering well
-Sea of Japan Minke is genetically unique – and declining to extinction
Korean markets
-North Pacific Minke whales: reported bycatch 458, actual 827

23

Give an example about how forensics can help elucidate cryptic species?

Cryptic species - bat species
Common pipistrelle and Soprano pipistrelle
•Thought to be same species, but calls different
•11% divergence in cytochrome b sequence
•Diverged 5-10 million years ago

24

What did Moritz state about Evolutionarily significant units?

Moritz 1994
-historical differences in spp are important
-define historial differences by reciprocal monophyly for mtDNA alleles
-to show significant divergence of nuclear allele frequencies

25

What are the ESU's of the Brown Kiwi?

3 Major clades (ESU)
-need care in augumenting the northernmost population on S island
-least branched on the Evo tree least Evo variation

26

Give two examples of Hybridisation

Red wolf
-may be a hybrid species from Grey wolves and Coyotes
-extinct in the wild
-captive animals are drifting away from the original spp

White-headed duck
-Estimated world population of white-headed ducks (1999): 9,400 – 16,400
-White-headed duck 1999: 1000 (Spain), up from 22 individuals in 1970s
-Ruddy duck 1999: 4,000 in UK, from 7 individuals introduced in 1940s
-Ruddy ducks disperse to Spain and hybridise

27

How can we decide which species to conserve?

•Pessimistic view: cannot realistically conserve all species
•Use phylogenies to decide how to conserve maximal genetic diversity

28

Give two examples of successful species cloning and reconstruction

Gaur (endangered Indian/South-east Asian bovine)
•Skin cell nuclei of gaur  cow eggs
•Tissue 8 years old
•40 embryos transferred to domestic cows
•Eight pregnancies, one birth

Banteng (Javan bovine with N ~ 8000 individuals)
•Skin cell nuclei of banteng  cow eggs
•Banteng nuclei from tissue frozen 23 years ago
•30 embryos transferred to domestic cows
•Two successful births

29

What can genetic methods be used to do?

•detect illegal practices
•identify taxonomic groups of conservation concern
•possibly help to boost nearly extinct populations