BIOL 121 (2011) Fall Exam 3 + Key

To have other 5 points your choices in matings needed

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Unformatted text preview: inting (Be sure to explain how you will determine which sex is imprinting) (10pts) GRADERS NOTE: 1) When parental males are true breeding blue and females are true breeding red, you can not determine imprinting by the fact that F1 butterflies are all red because maternal effects have the same results. So you need to cross F1 butterflies to each other to see if you get a 1:1 phenotypical ratio in the next generation (there are other options too). If you miss this part, 4 points are taken off. 2) The imprinting sex is the one whose gene gets inactivated. If you get this point wrong, 3 points are taken off. 3) When describing your crosses, you must indicate the genotypes of both parents, otherwise 2 points are taken off. 4) 3 points are taken off when you have the incorrect expected phenotypical ratio. 5) Any obvious wrong statement in your answer will give you some points off. 6 BIOL 121 Exam 3 12/5/2011 NAME: (b) Maternal effects (10pts) Mate dominant true breeding females with recessive tree breeding males and then repeat with a reciprocal cross (recessive true breeding females with dominant true breeding males). If maternal effects, you expect all offspring to be what the females genotype makes them (dominant in the first cross, recessive in the reciprocal cross). You can also confirm the maternal effects by mating heterozygotes with one another and expect to get all dominant offspring (because all females +/-) HOWEVER this only confirms maternal effects if you have the other matings listed above as this mating alone could be attributed to dominance not exclusively maternal effects. GRADERS NOTE: If you talked about the definition of maternal effect: “The phenotype of offspring is only determined by the GENOTYPE of mom”, you were awared 5 points. To have other 5 points, your...
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This note was uploaded on 01/16/2014 for the course BIOL 121 taught by Professor Dustinbrisson during the Fall '11 term at UPenn.

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