BIOLOGY 2C03 Lecture Notes - Homologous Recombination, Aneuploidy, Trisomy
5 Nov 2013
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This similarity in the pattern of chromosome inheritance and genetics inheritance is really a correlation. We need proof that a gene resides on specific chromosome. Sex linkage: genes for specific traits are carried on chromosomes. First mutation identified was for white (w) eyes. Wild type: flies with red eyes, carrying wildtype allele (w+) Mutant; any variation in eye colour, carrying mutant alleles. E. g. white eye colour, white allele (w or w-) Note: the gene for eye colour was called white after the mutant phenotype. Experiment 1: crossed white-eyed male to a red-eyed female. Result: 3,470 red;782 white and all white-eyed flies were male. Interpretation: morgan proposed that the eye colour gene is on the x chromosome. Females: two x chromosome = two alleles of the gene. Males: one x chromosome = one allele (hemizygous) Red-eyed females: w+/w+; two wild type alleles of the white gene. White-eyed male: w/y; one mutant allele of the white gene.
