Week #1

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Week #1
2010-01-28 18:01:49
Evolution Midterm 1

Human evolution, Origin of disease, Breast cancer
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  1. 3 main human livelstyles
    • Hunther/gatherer
    • Agricultural
    • Industrial
  2. Darwinian medicine/Evolutionary medicine
    Explanations of disease in the context of human natural selection and human environmental transitions
  3. Theory of human evolution
    Hunter gatherer socieites > modern humans migrate from origins in East Africa to other places > agricultural societies > industrial information
  4. 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
  5. 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
  6. How do you determine human origins?
    Analyze mutational changes during human evolution
  7. What types of effects can mutations have?
    • Negative
    • Positive
    • Neutral
  8. Haplotype
    • Common way of labeling mutational differences b/w humans
    • General term denoting genetic constitution of individual chromosome
    • Specific type: SNPs
  9. 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
  10. Genetic drift
    • Random chance changes frequency if specific allele or gene throughout entire gene pool
    • Nothing to do with selective forces
  11. PCR requirements
    • Thermostable DNA polymerase
    • Sequence information enabling synthesis of specific oligo
  12. Cloning requirements
    • Suitable host cell
    • Replicon
    • Means of attaching foreign DNA to replicon and transferring to host cell
  13. Polymerase Chain Reaction (PCR) steps
    • 1. Denature dsDNA by heating
    • 2. Allow primers to anneal
    • 3. DNA synthesis
  14. How do you sequence DNA?
    Chain termination method
  15. Chain termination requirements
    • Chain terminating nucleotides lack 3' OH groups
    • Have fluorescent labels
  16. Chain termination data
    • The peaks are fluorescence intensities at different times of passage through a sequencing gel
  17. 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)
  18. Approximately how many years ago did humans and chips share a common ancestor?
    ~6 million
  19. 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
  20. Tracing FEMALE lineages
    • Use mitochondrial DNA
    • Maternally inherited only
    • Male sperm mitochondria not passed to offspring
  21. Geographical distributions of polymorphisms
    • Y chromosome and mitochondrial DNA not identical
    • Due to males moving less than females
  22. Evidence that modern human diaspora came from a single source
    • Skeletal paleontology
    • Tool evolution
    • Language evolution
  23. Health and disease in hunter-gatherer societies
    High death rates (but same life-span as industrial)
  24. Causes of death in hunter-gatherer societies
    • Accident
    • Food shortage
    • Predation
    • Homicide
    • Parasitic disease
    • Osteoarthritis
    • Childbirth
  25. 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
  26. Fertile crescent in Middle Eastern Eurasia
    Earliest origin of highly organized agriculture and animal domestication
  27. 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
  28. How modern humans live in different environment
    • Activity levels
    • Diet
    • Exposure to infectious microbes
  29. Agricultural lifestyle has led to...
    • Exposure to animal viruses
    • Diseases enhanced by carb diets
    • High transmission of human-human disease pathogens
  30. Measles
  31. AIDs
  32. Thyphoid fever
  33. Pertusis
  34. Smallpox
  35. Stomach ulcers
  36. Tuberculosis
  37. Influenza
    Pigs, birds, dog
  38. First animal domesticated
    • Sheep
    • ~11,000 years ago
  39. Diseases in indrustrial environments influenced by...
    • Sedentary lifestyles
    • Longer average lifespans
    • Abudant food
    • Highly processed food
    • Exposure to synthetic chemicals
    • Increase in medical technology
  40. Diseases common in agricultural/industrial (absent from hunter/gatherer)
    • Diabetes
    • Myopia
    • Cancer
    • Heart disease
  41. Scientific evidence
    • All variables controlled except single variable being tested
    • Evidence must reproducible by others
    • Someone else reaching the same conclusion using different evidence