Dimples (D) and brown hair (A) are dominant traits. Answer the following questions based on the dihybrid cross shown: 1) What genotype(s) would result in a phenotype of dimples and brown hair? 2) What genotype(s) would result in a phenotype of dimples and blonde hair? 3) What genotype(s) would result in a phenotype of no dimples and brown hair? 4) What genotype(s) would result in a phenotype of no dimples and blonde hair? 5) What is the phenotypic ratio for this cross? (Be sure to use words to indicate which number goes with which phenotype!)
(1) Answers
1. DDAA, DdAa 2. DDaa, Dada 3. ddAA, ddAa 4. ddaa 5. The phenotypic ratio is 9:3:3:1 where 9 combinations will produce offspring with both dominant phenotypes (dimples and brown hair), 3 will produce offspring with one dominant phenotype and one receive phenotype (dimples, blonde hair), 3 will produce offspring with one receive phenotype and one dominant phenotype (no dimples, brown hair), and one will produce offspring with both recessive phenotypes (no dimples, blonde hair)
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