BISC 202 Lecture Notes - Lecture 12: Wild Type
7 Dec 2018
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Monohybrid crosses phenotypic ratio: 3:1 complete dominance, 1:2:1 incomplete dominance or co-dominance, 1:2 recessive lethality. Dihybrid crosses phenotypic ratio: 9:3:3:1 independent assortment. No linkage: 9:7 duplicate recessive epistasis. Both genes act on the same biosynthetic pathway in the same way. Homozygous mutant for one of the allele = mutant phenotype: 9:3:4 recessive epistasis. When one gene is homozygous recessive, its phenotype masks the other gene"s phenotype: 12:3:1 dominant epistasis. When one gene has a dominant allele, its phenotype masks the other gene"s phenotype: 9:6:1 dominant gene interaction. When both genes have a dominant allele, they interact to produce a new phenotype: 15:1 duplicate gene interaction. As long as one of the two genes has a dominant wildtype allele, the individual"s phenotype will be wildtype: 10:6 recessive suppressor with genotype. If the suppressor gene is homozygous recessive, it will mask the phenotype of the other gene with its own: 13:6 recessive suppressor without genotype.
