1. You hypothesize that a strain of plant with an unknown genotype is a heterozy
ID: 202413 • Letter: 1
Question
1. You hypothesize that a strain of plant with an unknown genotype is a heterozygote for the gene that controls fruit color. In this strain, the fruits are red. You cross it with a fully recessive tester strain that has white fruits and get the following phenotype frequencies in the progeny. 86 red 14 white a) What is the expected phenotype ratio if your hypothesis is that the unknown plant is a heterozygote? b) How many degrees of freedom are there? c) Can you reject your hypothesis that the unknown plant is a heterozygote? d) If you had 55 red and 63 white plants in your cross, would you reject your hypothesis? 2. Having graduated UNH, you get a job aimed at breeding dragons. You have the following genotype/phenotype relationships. B/- long wings A/- red eyes breathing a/a white eves breathing C/- ill-tempered D/- not fire b/b no wings c/c lovely d/d fire E/- loves to fly e/e afraid of heights You also have parental dragons with the following genotypes: Parent 1: A/a, B/b, c/c, D/d, E/e Parent 2: a/a, B/b, C/c, D/d, e/e What are the odds of obtaining a red eyed, long winged, ill tempered, fire breathing dragon that is afraid of heights? (assuming genes are not linked)Explanation / Answer
a- expected ratio is 1:1 if our hypothesis that the unknown plant is heterozygote
b- There are two phenotypes in the F1 progeny. So degree of freedom is number of phenotypes -1
= 2-1 = 1
c- Yes we reject the hypothesis that the unknown plant is the heterozygote.
d- In that, the ratio is red plant to white plant is almost 1:1 so in that case, we would have accepted the hypothesis.
2-
In the cross between Aa and aa chance of A_ genotype is 1/2
In the cross between Bb and Bb chance of B_ genotype is 3/4
In the cross between cc and Cc chance of C_ genotype is 1/2
In the cross between Dd and Dd chance of dd genotype is 1/4
In the cross between Ee and ee chance of ee genotype is 1/2
So overall chance of Red eye, long wing, ill-tempered, Fire breathing dragon which afraid of height is 1/2*3/4*1/2*1/4*1/2
3/128
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