MGY299Y1 Lecture Notes - Genotype Frequency, Sickle-Cell Disease, Allele Frequency
3 Jun 2013
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Exam soon covers up to lecture 09. In 1908 independently described concept that in large randomly mating population where no selection, mutation or migration - allele frequencies and genotype frequencies are constant. Expected genotype frequencies for aa is square of a allele frequency. When testing for deviance from hwe observed genotype data, calculate allele frequencies, calculate expected genotype frequencies under hwe and compare observed genotype frequencies to expected to see if statistically different. If genotyping assay is producing incorrect results perhaps because there is another genetic variation interfering with assay cause deviation from hwe. Estimates are very close between observed and expected. Chi square test p value of 1 infants no significant evidence of genotypes deviating from hwe. Observe more heterozygotes than expected; observe fewer ss; Statistical significance significant deviation from hwe in adults. Sickle cell anemia death in childhood so fewer ss homozygotes as adults. Excess of as heterozygotes these individuals have advantage: malaria survival.
