BIO220 Lecture 15 Flashcards
Conservation genetics
Summarize what Wilson said about biodiversity
loss of biodiversity:
- irreversible
- least predictable consequences
- earth is largely unstudied & unappricated
define: biodiversity
number & kinds of living organisms in a given area
interspecific variation is also known as…
species diversity
intraspecies variation is also known as…
genetic diversity
interspecies variation is studied by…
ecologists
intraspecies variation is studied by…
evolutionary geneticists
3 levels of genetic diversity
- within individuals (heterozygosity)
- between individuals of the same population
- between individuals of the same species
CONSERVATION GENETICS
applying genetic methods to conservation, restoration, and endangered species management
What happens genetically to declining populations?
- genetic drift
- inbreeding
- allee affects
- demographic stochasticity
= loss of genetic variation
Allee effect
positive correlation between population size or density and the mean individual fitness
- reproduction rate depends on pop’n density
demographic stochasticity
random differences among individuals in survivorship and reproduction -> variable pop’n growth rate
“random bad events”
does demographic stochasticity happen if individuals have the same average survival reproduction?
Yes
- doesn’t have to do with phenotype
- RANDOM
demographic stochasticity is most important in ___ populations
small
What matters more for small populations: genetics or demographics?
- Genetics: population decline => decreased Ne => extinction
- Demography: demographic stochasticiy => extinction before effects of genetics can manifest
Both have effect
- inbreeding affect demographics
- demographic stochasticity exacerbate lower Ne
what are the problem with cheetahs (genetically)?
very, very similar genetically
- MHC locus: can accept each other’s skin grafts
- low polymorphism
- low heterozygousity
problem with captive cheetas
- low sperm counts
- high disease load
How did genetic variation in cheetahs get so bad?
- historical bottleneck lowered Ne
- inbreeding when Ne was low lowered it even more
In the wild, most cheetah deaths are due to…
cubs die because mom goes hunting (75%)
- deaths are not related to genetics
Genetic diversity of wild cheetah
- MHC allele number: low compared to other mammals
- Nucleotide diversity: similar to other cats, high compared to dogs
- AA variation at MHC: similar to other cats
how do we measure genetic diversity?
- allele number
- nucleotide diversity
- AA sequence diversity
Florida panthers are a sub-species of…
mountain lion found in Florida
Problem with Florida panthers
Inbreeding depression:
- low sperm count
- 1 testicle
- 90* bend in tail
“Genetic rescue” of Florida panther goals
Translocation of 8 female pumas from Texas:
- increase genetic diversity
- improve population numbers
- reverse inbreeding depression
“Genetic rescue” of Florida panthers results
- more genetic variation w/in individuals
- N increase (4x)
- Ne increase (2x)
- increased heterozygosity = increased survivalship
WT vs. admixed panthers vs. backcross F1 panthers in terms of survival. Explain.
Backcross F1 has higher survival because higher heterozygousity. Admix was the first generation, so lower heterozygosity, but still higher than WT.
What was done to rescue genetic diversity of Swedish adders? What effect did this have?
20 male adders introduced to the isolated population in Sweden
- increase in population density & recruits (young -> adult)
- more variation at MHC locus
What happened to Prairie Chickens?
Fragmentation & elimination of prairie habitat caused pockets of very small populations -> low genetic diversity within each fragmented group
- egg hatching & male population size declining
What was done to rescue diversity of Prairie Chickens?
Translocation: put the isolated groups together
- more egg hatching & more males
What happened to the wolves in Scandinavia?
Hunted to near extinction
How was genetic diversity rescued in wolves?
Single immigrant wolf arrived:
- increase population size
- increase Ne
Inbreeding coefficient
How inbred a species is
- high = low genetic diversity
- low = high genetic diversity
Within ___ generations, the immigrant male wolf became related to every individual in the population
2.5
What happened to the wolf population long-term?
inbreding coefficient is starting to go up again, because male wolf has fathered every unique pup possible. Future matings are all between siblings/half-siblings.
Examples of human induced mortality
- hunting
- fragmentation
- road accidents
introduction/translocation has ___-term benefits
short
Are genetic rescues effective?
Yes, but only short-term
Genetic rescue is a ____ strategy
time-buying
How should we properly use genetic rescue strategies?
- Use it to temporarily increase population size and reduce likelihood of extinction
- Use gained time to fix underlying problem
- Eliminate/reduce factors that are causing endangerment
What is needed for long-term genetic health of endangered species?
Eliminate/reduce factors that are causing endangerment
