DISCUSSION QUSTIONS ON LINKAGE AND RECOMBINATION
Q1. An individual with cd genes was crossed with wild type + +. On test crossing F1, the progeny was + c 105, + d 115, cd 880, and + + 900. Distance between cd genes is:
a. 11 map units
b. 5.5 map units
c. 44 map units
d. 88 map units
Solution: The simplest way to solve this problem is to find the recombination frequency percentage, which is equal to the map distance.
Q2. A plant of genotype C/C;d/d is crossed to c/c;D/D and an F1 test crossed to c/c;d/d. If the genes are linked and 40 map units apart, the percentage of c/c;d/d recombinants will be?
A. 10%
B. 20%
C. 30%
D. 40%
Q3. The maximum recombination frequency between two genes is:
A. 100%
B. 80%
C. 50%
D. 10%
Q4. In Drosophila, the two genes w and sn are X-linked and 25 map units apart. A female fly of genotype w+ sn+/w sn is crossed to a male from a wild-type line. What percentage of male progeny will be w+ sn?
A. 0
B. 12.5%
C. 25%
D. 37.5%
Q5. Recombination frequencies ___
A. are the same for all genes.
B. arise from specific genetic exchange.
C. are the same for cis and trans heterozygotes.
D. decrease with distance
Q6. In crossing over
A. Genetic exchange occurs before chromosome replication
B. The probability of its occurrence decreases with increasing distance between the genes exchanged
C. Occurs between two loci very close together
D. The reciprocal exchange between homologous chromosomes is random
Q7. Which of the following is suitable for experiment on linkage?
A. aaBB x aaBB
B. AABB x aabb
C. AaBb x AaBb
D. AAbb x AaBB
Q8. AB genes are linked. What is the genotype of the progeny in a cross between AB/ab and ab/ab?
A. AABB and aabb
B. AaBb and aabb
C. AAbb and aaBB
D. AaBb and AaBb
Q9. Three genes a b and c show crossing over of 20% between a and b, 28% between b and c and 8% between a and c. Sequence of genes will be:
A. b a c
B. a b c
C. a c b
D. b c a
Q10. Distance between the genes a, b, c and d in map units is a-d = 35, b-c = 1, a-b = 6, c-d = 1.5 and a-c = 5. Find out the sequence of genes?
A. a d c b
B. a c d b
C. a b c d
D. a c b d
E. a d b c
Answer key:
a. 11 map units
b. 5.5 map units
c. 44 map units
d. 88 map units
Solution: The simplest way to solve this problem is to find the recombination frequency percentage, which is equal to the map distance.
Q2. A plant of genotype C/C;d/d is crossed to c/c;D/D and an F1 test crossed to c/c;d/d. If the genes are linked and 40 map units apart, the percentage of c/c;d/d recombinants will be?
A. 10%
B. 20%
C. 30%
D. 40%
Q3. The maximum recombination frequency between two genes is:
A. 100%
B. 80%
C. 50%
D. 10%
Q4. In Drosophila, the two genes w and sn are X-linked and 25 map units apart. A female fly of genotype w+ sn+/w sn is crossed to a male from a wild-type line. What percentage of male progeny will be w+ sn?
A. 0
B. 12.5%
C. 25%
D. 37.5%
Q5. Recombination frequencies ___
A. are the same for all genes.
B. arise from specific genetic exchange.
C. are the same for cis and trans heterozygotes.
D. decrease with distance
Q6. In crossing over
A. Genetic exchange occurs before chromosome replication
B. The probability of its occurrence decreases with increasing distance between the genes exchanged
C. Occurs between two loci very close together
D. The reciprocal exchange between homologous chromosomes is random
A. aaBB x aaBB
B. AABB x aabb
C. AaBb x AaBb
D. AAbb x AaBB
Q8. AB genes are linked. What is the genotype of the progeny in a cross between AB/ab and ab/ab?
A. AABB and aabb
B. AaBb and aabb
C. AAbb and aaBB
D. AaBb and AaBb
Q9. Three genes a b and c show crossing over of 20% between a and b, 28% between b and c and 8% between a and c. Sequence of genes will be:
A. b a c
B. a b c
C. a c b
D. b c a
Q10. Distance between the genes a, b, c and d in map units is a-d = 35, b-c = 1, a-b = 6, c-d = 1.5 and a-c = 5. Find out the sequence of genes?
A. a d c b
B. a c d b
C. a b c d
D. a c b d
E. a d b c
Answer key:
In this article you have talked about the linkage and recombination of genes. In this way, Biology students can get a parcel data. Peruse assignment help service and find out about How to decide recombination recurrence for a couple of genes.
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