Lecture 22 - Case studies in genetics Flashcards
what are the four processes that lead to evolution/
mutation
genetic drift
gene flow
natural selection
how is evolution relevant to medicine?
> human genotypes are the result of evolution, including genetic diseases
pathogens evolve, sometimes very quickly
human susceptibility to pathogens often has a genetic basis
What is an example of a genetic disease?
> huntingtons disease
Why is the prevalence of Huntingtons disease greater in tasmania than in NSW?
because there is a smaller population in Tasmania, so less gene flow and genetic drift.
What is another example of evolution being important in medicine?
> in antibiotic resistance
“staph” bacteria are one of the most common causes of skin infection in humans
1943 - penicillin used to treat staph infections
1945 - 20% of staph infections resistant to penicillin
“MSRA” resistant to methicillin, penicillin, and typically aditional other antibiotics
What are some examples of human pathogen susceptibility and genetics?
> malaria and sickle cell anemia and HIV
Quick evolution in HIV
Some humans have immunity to HIV
homozygous delta32-CCR5 means that HIV can’t bind and enter the cell.
the delta32-CCR5 mutant prevents the expression of a functional receptor and consequently prevents viral binding, Virus-cell fusion and entry.
How is evolution relevant to agriculture?
> low variation in crops susceptible to pathogens
heirloom varieties and wild relatives are important sources of genetic diversity and crop traits
new cropping strategies are being developed based on evolutionary theory
what is an example of crops susceptible to pathogens ?
Irish potato blight
> in diverse crops, the blight hits and destroys the potatoes susceptible, however, the other resistant potatoes in the crop live on.
> in cloned potato crops, blight hits and destroys the whole crop because there is no diversity and therefore no resistant variants.
What is special about heirloom and wild relatives?
they are important to maintain genetic diversity and crop traits
What are the crop strategies being developed based on evolutionary theory?
field with refuge to combat recessive pesticide resistant bugs
how is evolution relevant to conservation?
> small populations loose genetic diversity
natural history of many imperiled species not conductive to quick evolutionary change
tools from evolutionary biology can recognise diversity
homozygous recessive traits increase in frequency as inbreeding exposes more of them.
What are the key concepts from this lecture?
> genetic diversity underlines future evolutionary potential
evolutionary history shapes present-day genetic diversity
natural selection is frequently context dependent; phenotypes with high fitness in one context may have low fitness in a different context.
evolutionary principles are highly relevant to human endeavors
