Monday, 6 December 2010

Epigenetics & the Environment

Identical Twins: Pinpointing Environmental Impact on the Epigenome
  • Nature or nurture? --BOTH
  • identical twins share all genes
  • fraternal twins share half the genes
  • as twins grow older, their chromosomes have different epigenetic tags attached
  • when schizophrenia occurs in identical twins, in 50% of cases both develop the disease while in fraternal twins, only 10-15% of the time do both twins develop it
  • both identical twins don't develop the disease 100% of the time = other factors involved
Lick Your Rats
  • Highly nurtured (licked) rat pups = calm adults
  • Little nurtured rat pups = anxious adults
  • Anxiousness is a + in wild, while - in domesticated environment
  • relaxedness is - in wild, while + in domesticated environment
  • epigenetic patterns can be changed
  • licking releases GR gene
  • more of GR means more relaxedness and faster recovery from stress
Nutrition and the Epigenome
  • mother's diet while pregnant affects embryo structure and critical factors that stay through adulthood
  • agouti gene in mice is unmethylated = yellow coat color, obesity and prone to diabetes, cancer
  • agouti gene is methylated = brown coat color, mouse has a low disease risk
  • Shortage of food for grandfather = extended lifespan of grandchildren
  • more food for grandpa = grandkids' lifespan shortened by diabetes, heart disease
  • disease risk can be predicted by looking at family health history
Epigenetics and the Human Brain
  • Child abuse and suicide may be epigenetically linked
  • People who commit suicide have less-active ribosomal RNA
  • the abused suicide victims had an epigenetic tag on the GR gene
  • GR gene receives similar epigenetic tag in rat pups who receive low quality care mothers
  • The gene for REELIN protein has is more active in schizophrenic brains than normal brains
  • 60 genes = difference between psychiatric patients and healthy people
  • drugs used to treat mental illness change gene expression sometimes
  • Drugs of abuse trigger epigenetic changes, affect hundreds of genes at a time

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