Biology 1202B Chapter Notes - Chapter 11: X Chromosome, Drosophila Melanogaster, Testis Determining Factor
15 Mar 2016
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Biology 1202b: chapter 11 genes, chromosomes, and human genetics. 11. 1a the principles of linkage and recombination were determined with drosophila. Scientists used this fruit fly as a model of mendel"s earlier experiments. Groups of genes that tended to assort together in crosses were believed to be carried on the same chromosome. Alfred sturtevant developed the insight that resulted in the construction of the first genetic map showing the relative order of genes on a chromosome: he estimated the distance separating genes. They didn"t have microscopes to see the genes, so they used indirect measure of distance: genes sitting relatively far apart would be more likely to be separated during cross over in meiosis. Notation for a wild-type allele is always made by adding superscript + to mutant allele notation: ant p+ refers to recessive allele giving a normal phenotype when homozygous. Began with true-breeding normal red eyes and normal wing lengths and true-breeding recessive purple eyes and vestigial wings.
