98ex1 - Student name _ AGR 3303 - Genetics 5 Oct 1998...

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Student name ____________________________ AGR 3303 - Genetics 5 Oct 1998 University of Florida - Fort Lauderdale Exam #1: PARTICULATE GENETICS Multiple choice (60 pts.) Please read these carefully . One and only one response (a, b, c, d, or e) completely and correctly answers the question, or completes the statement. Circle the appropriate response and turn in this exam. Make sure your circle is unambiguous. Take time to relax. (Suggestion: put the problem into gene symbols, if that helps you to visualize the problem and its solution.) 1. Green colorblindness in humans is a sex-linked recessive trait. In a family, the older son has normal vision, whereas the younger son is colorblind. One can realistically surmise: a. the mother was homozygous for colorblindness b. the father was homozygous for colorblindness c. the father was heterozygous for color blindness d. the mother most probably was colorblind e. none of the above 2. Coat color in dogs depends on the action of at least two genes. At one locus a dominant epistatic inhibitor of coat color pigment ( I_ ) prevents the expression of color alleles at another independently assorting locus, thereby producing white coat color. When the recessive condition exists at the inhibitor locus ( ii ), the alleles of the second locus will be expressed, iiB_ producing black and iibb producing brown. When dihybrid white dogs are mated, what would be the phenotypic ratio in the offspring? a. 12:3:1 b. 9:7 c. 9:3:3:1 d. 3:1 e. 1:2:1 3. What single information would most help in predicting genotypic frequencies of the progeny resulting from a cross? a. the number of chromosomes b. the allelic relationship, i.e. dominance, incomplete dominance, codominance c. the frequency of the various possible parental phenotypes d. the parental gametes e. the parental phenotypes 4. A man learns that both his parents had Huntington's disease, which is caused by a dominant autosomal allele. What is the chance that he will have the disease?
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AGR 3303 - Genetics, University of Florida - Fort Lauderdale Page 2 / 9 a. 0% b. 25% c. 50% d. 75% e. 100% 5. Color of chickens is determined by interacting loci: AA or Aa give white, aaBB or aaBb give colored, and aabb produces white. What are the phenotypic frequencies of the offspring from a cross between two fully heterozygous chickens? a. 15 white : 1 colored
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This note was uploaded on 07/30/2011 for the course AGR 3303 taught by Professor Gallio during the Fall '08 term at University of Florida.

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98ex1 - Student name _ AGR 3303 - Genetics 5 Oct 1998...

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