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Unformatted text preview: BICD100 FA2011 Problem Set #1: KEY 1) . In Mimulus (monkeyflower), plant stems can be either smooth or hairy, and this difference is determined by a single gene, H (call H the dominant allele and h the recessive allele). Examine the results of the following crosses. For each cross, indicate the genotypes of the parents and progeny: cross# parents progeny 1 hairy X hairy all hairy HH HH HH (one of these parents could be Hh, but not both) 2 hairy X hairy 3/4 hairy, 1/4 smooth Hh Hh HH & Hh hh 3 hairy X smooth 1/2 hairy, 1/2 smooth Hh hh Hh hh 4 hairy X smooth all hairy HH hh Hh 2). Flour beetles may be red or ebony, and this difference in body color is due to a single gene. A flour beetle with a red body is crossed with another beetle that has an ebony body. Approximately half the F 1 progeny have red bodies, and the other half have ebony bodies. Indicate for each of the following statements whether it could be true based on this information, and For each statement you indicate could be true, diagram a cross that could be done using only the F 1 progeny of the cross described above to prove whether the statement is true or false. Indicate the phenotypes of the beetles used for the cross, and the expected proportion of red and ebony progeny if the statement is true. a. Red is dominant to ebony b. Ebony is dominant to red Could be true. Could be true. Let R be dominant allele, r recessive Let E be dominant allele, e recessive Then the original cross would have been: Original cross would have been: Rr (red) X rr (ebony) --> 1/2 Rr (red), 1/2 rr (ebony) ee (red) X Ee (ebony) --> 1/2 red (ee), 1/2 ebony (Ee) Diagnostic crosses: Diagnostic crosses: 1. red (Rr) X red (Rr) -> 3/4 red, 1/4 ebony 1. red (ee) X red (ee) --> all red 2. ebony (rr) X ebony (rr) --> all ebony 2. ebony (Ee) X ebony (Ee) --> 3/4 ebony, 1/4 red 3.) When Mendel crossed a true-breeding green pod line with a true-breeding yellow pod line, the F1 progeny all had green pods. When these F1 plants were allowed to self fertilize, the F2 progeny were as follows: 428 with green pods and 152 with yellow pods. Use a chi squared test to determine how well these data fit the expected results for a trait controlled by dominant and recessive alleles of a single gene. Include in your answer your hypothesis, the expected values you are using, the value of chi squared, the p value and your conclusion (accept or reject null hypothesis?) Hypothesis: data fits Mendelian ratio 3 dominant: 1 recessive. Given 580 progeny, we Hypothesis: data fits Mendelian ratio 3 dominant: 1 recessive....
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This note was uploaded on 01/16/2012 for the course BICD 100 taught by Professor Nehring during the Fall '08 term at UCSD.
- Fall '08