Day 3- Darwinian Medicine and Evolutionary Genetics

Levels of causation

both proximate and ultimate explanations need to understand traits and disease

Evolutionary processes

All forces of evolution are important for understanding traits and diseases

Reproductive success

Natural selection maximizes reproductive success not health and longevity

Trade-offs

changes in traits that improve fitnesses can change other traits that decrease fitness

Phylogeny

Tracing phylogenetic relationships can provide insights into health and diseases 

Mismatches

Diseases risk for other organisms living in environments that differ from those which their ancestors evolved

Proximate causes

mechanistic causes; explains trait immediate physiological or environmental factors

Ultimate causes 

Evolutionary causes; explains traits in terms of evolutionary forces acting on them 

Levels of causation example: Sickle cell

(what are the proximate causes or the ultimate causes)

Proximate: sickle cell anemia is due to mutated hemoglobin that causes cells (hypoxia)

Ultimate causes: sickle cell anemia is duet o selection for malaria resistance among heterzyogote carriers of traits

Evolutionary proccesses?

mutation, random genetic drift, natural selection and gene flow all impact traits and diseases 

Reproductive success

Natural selection works to increase fitness (NOT HEALTH)

ie: prostate cancer thing;

Trade-offs

Changes in traits that improve fitness can change other traits that decrease fitness

(bipedal from quadrupedal apes)

What was the trade off with humans?

benifits: free hands for intensive non-locomotive use, mor eenergy efficent, greater FOV

costs: lower back problems mechaniscal issues wqith ankels and knees hernias

Phylogeny

Understanding evolution of species, populations, pathogens can provid einsights into traits and diseases

Mismatch

Disease risks differ for organisms living in enviorments that differ from those in which their ancestors evovled; not one enviorment which we are adapted

Selective sweep definition

Beneficial mutation increasing in frequency > eventually leading to fixation

Also near the mutation there is a reduction or elimination of variety

Positive selection

causes the new mutation to reach fixation super quickly that leads to other linked alleles hitchhike

signs of a selective sweep?

Increased differentiation + long haplotypes

GWAS

observational study to test whether any variants are associated w/ a trait

What is the major concern with genetic testing 

false positive bc there are so many variants *could happen just by chance)