CAS BI 216 Lecture Notes - Lecture 4: Sister Chromatids, Heterogametic Sex, Drosophila Melanogaster
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Lecture 4 1/31/17 (chapter 3 and chapter 4: gene interaction and allele interaction, 9:3:3:1 ratio - pigments. But if there is incomplete dominance at each locus. You end up having a gradient: modifications, incomplete penetrance. Mutant of wt phenotype even though genotype predicts mutant less penetrance = harder to notice; characterize; understan: variable expressivity. Mutant, but phenotype varies from cell to cell; individual to individual: example: retinoblastoma - in people who inherit one mutant allele of rb. Number of x chromosomes/ number of atusome sets. 0. 5 = male; 1 = female; 0. 5 - 1 intersex: humans. Other copy of chomosome = homolog: homolog to homolog - not-sister chromatids, each chromatid is either maternal or paternal. I (a b, a b) and ii (a b, a b) The only white ones were male: assigned the gene -> w+ (wild type - red); w (white) Red (xw+ / xw+) x (xw/ y) => (xw+/xw) x (xw+/y) => (xw.