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3 main human livelstyles
- Hunther/gatherer
- Agricultural
- Industrial
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Darwinian medicine/Evolutionary medicine
Explanations of disease in the context of human natural selection and human environmental transitions
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Theory of human evolution
Hunter gatherer socieites > modern humans migrate from origins in East Africa to other places > agricultural societies > industrial information
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Evolution of fatal diseases
- 1900 - Frequent cause of death: pneumonia/influenza, tuberculosis, diarrhea/enteritis
- Caused by communicable bacterial or viral diseases
- Since 1940s - cardiovascular disease, cancer, degenerative diseases
- Caused by longer lifespans
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Natural selection
- Any variation will be naturally selected if it increases the probability that an organism will...
- 1. Survive throughout entire reproductive period
- 2. Produce many progeny
- 3. Protect these progeny so that they survive to reproduce
- Selection principally acts at the levels of genes
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How do you determine human origins?
Analyze mutational changes during human evolution
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What types of effects can mutations have?
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Haplotype
- Common way of labeling mutational differences b/w humans
- General term denoting genetic constitution of individual chromosome
- Specific type: SNPs
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Single nucleotide polymorphisms (SNP/snips)
- On a single chromatid that can be associated with human characteristics
- Wikidpedia: DNA sequence variation occurring when a single nucleotide — A, T, C, or G — in the genome (or other shared sequence) differs between members of a species
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Genetic drift
- Random chance changes frequency if specific allele or gene throughout entire gene pool
- Nothing to do with selective forces
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PCR requirements
- Thermostable DNA polymerase
- Sequence information enabling synthesis of specific oligo
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Cloning requirements
- Suitable host cell
- Replicon
- Means of attaching foreign DNA to replicon and transferring to host cell
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Polymerase Chain Reaction (PCR) steps
- 1. Denature dsDNA by heating
- 2. Allow primers to anneal
- 3. DNA synthesis
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How do you sequence DNA?
Chain termination method
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Chain termination requirements
- Chain terminating nucleotides lack 3' OH groups
- Have fluorescent labels
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Chain termination data
- The peaks are fluorescence intensities at different times of passage through a sequencing gel
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454 sequencing
- Highly parallel
- 1. Dilute DNA sequence so that only one DNA sequence will attach to a single bead
- 2. Amplify the fragments on the surface of the beads – each bead is a PCR reaction
- 3. Beads put on a picotiter plate
- 4. Apply pyrosequencing – each time you pass a solution over the plate to fill the well with a T nucleotide and when it gets incorporated there will be a flash of light (repeat with the other nucleotides)
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Approximately how many years ago did humans and chips share a common ancestor?
~6 million
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Tracing MALE lineages
- Use Y chromosome
- Only 1 Y chromosome = no recombination
- Haplotype markers passed unchanged from father to son
- High rate of mutation b/c large junk DNA
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Tracing FEMALE lineages
- Use mitochondrial DNA
- Maternally inherited only
- Male sperm mitochondria not passed to offspring
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Geographical distributions of polymorphisms
- Y chromosome and mitochondrial DNA not identical
- Due to males moving less than females
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Evidence that modern human diaspora came from a single source
- Skeletal paleontology
- Tool evolution
- Language evolution
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Health and disease in hunter-gatherer societies
High death rates (but same life-span as industrial)
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Causes of death in hunter-gatherer societies
- Accident
- Food shortage
- Predation
- Homicide
- Parasitic disease
- Osteoarthritis
- Childbirth
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Diseases in hunter/gatherer societies
- Non-communicable dieseases rare
- Populations not large enough or dense enough to maintain and spread infectious diseases
- Irregular contact with other bands
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Fertile crescent in Middle Eastern Eurasia
Earliest origin of highly organized agriculture and animal domestication
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Hunter/gatherer vs Agricultural diets
- Hunter energy sources
- 65% lean game, wild fowl, eggs, fish, shellfish
- 35% fruits, vegs, nuts
- American energy sources
- 55% cereal, grains, milk, sugar, alcohol
- 28% meat, poulty, eggs, fish, shellfis
- 17% fruits, vegs, nuts
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How modern humans live in different environment
- Activity levels
- Diet
- Exposure to infectious microbes
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Agricultural lifestyle has led to...
- Exposure to animal viruses
- Diseases enhanced by carb diets
- High transmission of human-human disease pathogens
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Influenza
Pigs, birds, dog
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First animal domesticated
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Diseases in indrustrial environments influenced by...
- Sedentary lifestyles
- Longer average lifespans
- Abudant food
- Highly processed food
- Exposure to synthetic chemicals
- Increase in medical technology
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Diseases common in agricultural/industrial (absent from hunter/gatherer)
- Diabetes
- Myopia
- Cancer
- Heart disease
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Scientific evidence
- All variables controlled except single variable being tested
- Evidence must reproducible by others
- Someone else reaching the same conclusion using different evidence
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