Question 5

Practice: Simple Me 1.) An albino corn snake is crossed with a normal-colored corn snake. The offspring are all colored. When these first-generation progeny snakes are crossed among themselves, they produce ninant 32 normal-colored snakes and 10 albino snakes. a albinism A normal caley a. Which trait is dominant and which is recessive? Come up with a letter scheme for the gene involved. normal color is dominand and albinism is recesive. b. Which of these phenotypes is controlled by the dominant allele? nov mat colored phenotype. You conduct a test cross with a normal-colored female snake. This produces 10 normal- Parents: colored and 17 albino offspring. What are the genotypes of the parents and the offspring? Aa normal colored aq albing offspring Aaand aa 2.) Consider an individual with the following Genotype: Aa bb CC Dd ee Ff a. What percentage of their gametes will be a? 50%. What percentage of their gametes will be b? too / . C . What percentage of their gametes will be D? 507. d. What percentage of their gametes will be D F ? (hint: the two probabilities multiply) 25 7 . f . e. What percentage of their gametes will be b of? 25 /. How many different gametes can this person make? 8 3.) Consider the following cross: Ff Hh BB MM Gg x Ff hh bb Mm gg . What fraction of the offspring will be Gg? 1/2 b. What percentage will be hybrid for the "B" gene? 186%. c. What percentage of the offspring will have the M phenotype? 160/. d. What percentage will be pure-breeding "M" ? 507, 4.) Two healthy parents have a child who is later diagnosed with cystic fibrosis. b. a. What is the genetic term for this kind of disease? autosomal recessive Using Mendel's pattern, pick a letter for this gene and give the genotypes of the parents and the child. Parents' Cc x Cc Child:cc Cnormal allele and & cysticfibrosis CC C . What are the odds that their next child will also have cystic fibrosis? 5.) You are working in the lab with strains of Drosophila that have either normal legs or abnormally Li short legs and you are studying the gene responsible. You know that normal legs are dominant to short legs. You come across a misplaced fly with normal legs, but you are not sure of his genetic background and you want to keep him in your experiments. a. (Without doing a molecular analysis), How could you figure out whether he was heterozygous or homozygous for the leg gene that you are studying? (Describe what you would do and how the results would answer the question.) b . What is the procedure you described above called? Test cross LL XAI a) cross the's, short Legally, offspring have short legs, the original is zygous. if all offspring have norreal legs gioal Fly is likely homozygous dominant. yous dominant LL up gous 21. and genotype LI normal legs legs. Cross LL X hol