Bios101 Problem Set Two

Please answer these questions on a separate sheet(s) of paper, and please type. Small, handwritten figures on an otherwise typed document are acceptable. It is imperative that no part of your answer be copied directly from an online source, or from another student, either in this class or from a previous year. For answers that require research, please cite your sources. Yahoo answerare not appropriate sources and please do not copy any material directly from them. This problem set is due on safe assign, the due date being listed on the syllabus, and is very firm.

1. (one point) A man who has type B blood fathers offspring with a woman who has type A blood. Their first child, a girl, has type O blood. a) Diagram this cross and include pedigree information as well. b) What proportion of the gametes from the mother have the IA allele? c) What would be the probability that their SECOND child, assuming they have one, will have type O blood? Diagram this cross as well and include pedigree information if needed to explain your conclusion.

2. (one point) A man and a woman walk into a genetic counselors office. The mans brother has recently been diagnosed with Duchenne muscular dystrophy. The woman has no history of the illness in his family. a) They are concerned about having an affected child themselves. The woman is pregnant with a girl. Diagram this cross. What is the chance that the child the woman carries will have the disorder? b) If they have additional children, would a sperm or egg donor help to decrease the chance of an affected child?

3. (two points) A Drosophila melanogaster female with cinnabar eyes and normal wings is crossed to a D. melanogaster male with red eyes and vestigial (small) wings. The F1 are all red-eyed with normal wings. The F1 are allowed to cross with each other, and produce the following offspring. 57 red eyed normal wings 14 red eyes vestigial wings 13 cinnabar eyes normal wings 6 cinnabar eyes vestigial wings One of the cinnabar eyed vestigial winged females is cross with one of the female F1. The results are as follows. 27 red eyed normal wings 24 red eyes vestigial wings 23 cinnabar eyes normal wings 26 cinnabar eyes vestigial wings a) What genetic system do the results of this cross indicate? How many loci, how many alleles? b) Diagram both crosses and explain the results.

4. (two points) A female Drosophila with a yellow body and white eyes is crossed with a male that has normal (tan) body color and normal (red) eyes. Both lines are true-breeding. The resulting offspring are as follows. All females have normal (tan) bodies and normal (tan) eyes, all males have yellow bodies and white eyes. a) What genetic interaction seems to be the case here? Based on these results alone, can you tell if yellow bodies and white eyes are caused by one, or two loci? Now, imagine that the F1 females from the above cross is crossed to the males with yellow bodies and white eyes. The resulting F2 offspring are as follows. MALES Females 44 Yellow body white eyes 45 Yellow body white eyes 6 Yellow body red eyes 5 Yellow body red eyes 3 Tan body white eyes 5 Tan body white eyes 47 Tan body red eyes 45 Tan body red eyes b) Diagram this cross, starting with the P1 and proceeding to the F2. Are the loci sex linked? c) Are the loci linked? Do a chi-square test of goodness of fit, and determine whether independent assortment is falsified. Look up the actual genetic loci and state whether this hypothetical cross makes sense.

5. (two points) In corn snakes, alleles at two loci control color pattern. Normal individuals (and this is the type seen usually seen in the wild) are patterned with conspicuous black outline around red brick red blotches. Individuals which are homozygous recessive cinder condition are black and white patterned, with no red. Amelanistic individuals are homozygous recessive for a condition that inhibits black color-they have the red, but no black outlines. a) An cinder snake from a true-breeding line is crossed to a lava snake from a true breeding line. The F1 offspring are all raised to adulthood. What color are they? b) Now, imagine that an F1 male is crossed to an F1 female. 16 eggs hatch. Predict the colors of the offspring. c) Go online to the corn snake genetics calculator, http://www.corncalc.com/index.jsp, conduct four crosses, and diagram each one.