01:119:115 Lecture Notes - Lecture 13: Thomas Hunt Morgan, Homomorphism, Embryology
17 Nov 2016
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~ 1902: scientists began to develop the chromosome theory of inheritance : genes have specific loci on chromosomes, chromosomes undergo segregation and independent assortment. Today genes are located on chromosomes. (fig 15. 2b: the chromosome theory of inheritance, morgan"s use of drosophila. Drosophila melanogaster, a common species of fruit fly. A convenient organism for genetic studies: 100"s offspring, eggs every two weeks, four pairs of chromosomes. Evidence that chromosomes are the location of mendel"s heritable factors . Mutation - dna is not making the protein it"s supposed to be making. Trait named after mutation: wild type, mutant phenotype, correlating allelic behavior with chromosome pair. Results same as phenotypic ratio as mendel"s pea plants. How is this explained by chromosomes? (fig 15. 4b) Inheritance patterns on sex chromosomes: inheritance of x-linked genes. Act homologous in meiosis, some regions synapse + crossing over. Sex-linked gene can be located on either sex chromosome. Humans 2 sex chromosomes: x & y.
