BIOC14H3 Lecture Notes - Lecture 9: Twin Study, Sickle-Cell Disease, Nucleosome
Document Summary
Genetically we are similar, but epigenetically we are very different. Part of our differences of epigenetics comes from out predispositions to various diseases. Still 99. 5% of dna is shared: dizygotic twins share 50% of segregating polymorphism. Think that smoking is environmental but in fact smoking is. Genetic factors and environmental factors together cause human disease. Environmental studies problems: only the non-shared environment is important. Genetic problems : in psychiatric diseases (ex autism) heritability is about 90%, bipolar is. 80%, schizophrenia is 70: gwas can only explain about 7% of that heritability, there are unexplained heritability, we can only explain a tiny tiny fraction of heritability. Dna sequence based research programs comes from numerous studies in a. Sexual dimorphism (effects one sex more often the other) A lot of parameters make complex diseases different from simple mendelian disorders more differences than sequence variation this is because this analysis has been so.
