Deck 5: Linkage, Recombination, and Eukaryotic Gene Mapping

Question 1

From the cross AB/ab *ab/ab,what is the recombination frequency if the progeny numbers are 72 AB/ab,68 ab/ab,17 Ab/ab,and 21 aB/ab?

A)0.213
B)0.271
C)0.500
D)0.787
E)cannot be determined

Answer 1

0.213

Question 2

Consider the following three-point cross: A_____B_____C  a_____b_____c
A b c a b c
Which of the following is not a possible genotype? Consider both recombined and nonrecombinant.)

A)A_____B_____C a b c
B)a_____B_____C a b c
C)A_____B_____C A B C
D)A_____b_____C a b c
E)a_____b_____c a b c

Answer 2

C
A_____B_____C A B C

Question 3

If genes A and B are linked,what is the maximum percentage of recombinant gametes that can be produced during gametogenesis?

A)0%
B)25%
C)50%
D)75%
E)100%

Answer 3

C
50%

Question 4

What is the order of the linked genes R,S,and T if the distance between R and S is 22 m.u.,the distance between S and T is 8 m.u.,and the distance between R and T is 14 m.u.?

A)R S T
B)S T R
C)T R S
D)cannot be determined

Question 5

You calculate an interference of 0.59.What does this number tell you?

A)You will not observe 59% of expected double crossovers.
B)You will observe 59% double crossovers.
C)You will observe 41% double crossovers.
D)You will observe 59% of expected double crossovers.

Question 6

In performing a dihybrid cross,you expect to see a 9:3:3:1 ratio.What is a good explanation if you do not see a 9:3:3:1 ratio in a dihybrid cross?

A)The two genes are not linked.
B)The two genes are linked.
C)One of the genes is dominant over the other.
D)The two genes assort independently.
E)This proves that Mendel's laws are incorrect.

Question 7

If a heterozygous parent AB/abis test-crossed to a homozygous recessive ab/ab),what will the progeny phenotypic ratio be if genes A and B are completely linked?

A)1AB:1Ab:1aB:1ab
B)9AB:3Ab:3aB:1ab
C)1AB:1ab
D)none of the above

Question 8

Which is NOT an acceptable notation for two linked genes,A and B,in a heterozygote?

A)
B)
C)
D)AB/ab
E)All of the above are acceptable notations.