geneticsprobset1 - Genetics - Problem Set I Work on the...

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Genetics - Problem Set I Work on the problems individually; if you do not understand them, ask for help from your lab instructor, Dr. Faeth, or post on the discussion boards. Note : standard notation in Drosophila (fruitfly) genetics uses the symbol + to show dominance. You can convert this notation to capital/lowercase if you want. They also use the term “wild type”, which basically means “normal”, or what you see in natural populations. A. Genetics Problems 1. Several black guinea pigs of the same genotype were mated and produced 29 black and 9 white offspring. What would you predict the genotypes of the parents to be? 2. Heterozygous black Bb guinea pigs are mated to homozygous recessive bb whites. Predict the genotypic and phenotypic ratios expected from backcrossing the black progeny to ( a ) the black parent type (Bb), ( b ) the white parent type (bb). 3. In Drosophila , sepia colored eyes are due to a recessive allele s and wild type (red eye color) to its dominant allele s+ . Sepia-eyed females are crossed to pure wild type males. What phenotypic and genotypic ratios are expected if the F1 males are then backcrossed to sepia-eyed parental females? 4. Short hair is due to a dominant gene L in rabbits, and long hair to its recessive allele l . A cross between a short-haired female and a long-haired male produced a litter of 1 long-haired and 7 short-haired bunnies. (a) What are the genotypes of the parents? (b) What genotypic ratio was expected in the offspring generation? (c) How many of the eight bunnies were expected to be long-haired? 5. A dominant allele W produces wire-haired texture in dogs; its recessive allele w produces smooth hair. Heterozygous wire-haired individuals are crossed to each other. Each of their offspring are then crossed to smooth-haired animals. Determine the expected genotypic and phenotypic ratios for each of the possible crosses that have happened here. 6. Black wool of sheep is due to a recessive allele b and white wool to its dominant allele B . A white buck is crossed to a white ewe; both carry the allele for black. They produce a white buck lamb.
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This note was uploaded on 04/02/2008 for the course BIO 187 taught by Professor Douglasgreen during the Spring '07 term at ASU.

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geneticsprobset1 - Genetics - Problem Set I Work on the...

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