Life Sciences Questions and Answers – Gene Interaction

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This set of Life Sciences Multiple Choice Questions & Answers (MCQs) focuses on “Gene Interaction”.

1. The Phenomenon of two or more than two genes affecting the expression of each other is called ___________
a) Crossing over
b) Pairing
c) Gene interaction
d) Linkage
View Answer

Answer: c
Explanation: Mendel described every character is influenced by the particular expression of the gene, but when the characters are controlled by the combination of more than one gene, called gene interaction.
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2. Which of the following ratio shows complementary gene interaction?
a) 9:7
b) 15:1
c) 1:2:1
d) 9:3:3:1
View Answer

Answer: a
Explanation: Complementary gene interaction is first discovered by William Bateson and Reginald Punette in 1906. 9:7 ratio shows the 9 offspring have both dominant genes, while 7 is having either one dominant or both recessive.

3. Which of the following does not show Mendel’s law of inheritance?
a) Masking gene interaction
b) Epistasis
c) Supplementary gene interaction
d) Codominance
View Answer

Answer: d
Explanation: Codominance is the phenomenon where both the alleles of the gene pair in a heterozygote are expressed and resulting in offspring which is neither dominant nor recessive. Example: AB blood group.
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4. Crossing of two white flowers gives a colored flower, this shows complementary gene interaction.
a) True
b) False
View Answer

Answer: a
Explanation: Two true varieties of white flowered plant crossed and result in purple color progeny which shows that there must be some enzyme secreted by both the dominant alleles which contributed in the color of the flowers.

5. What is epistasis?
a) Type of linkage
b) Masking or modifying gene effect
c) Upper portion of a chromosome
d) Group of genes
View Answer

Answer: b
Explanation: It is a non-allelic suppression which involves two pairs of alleles. It can suppress both dominant or recessive alleles.
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6. Which of the following is NOT the type of epistasis?
a) Dominant
b) Recessive
c) Collabrative
d) Supplementary
View Answer

Answer: c
Explanation: Epistasis can be of many types based on the ability of an allele in masking and modification of gene effects. It can be of dominant, recessive, complementary or supplementary.

7. Choose the correct ratio, which shows the masking gene interaction?
a) 12:3:1
b) 9:3:4
c) 1:2:1
d) 9:7
View Answer

Answer: a
Explanation: Masking gene interaction is also recognized as dominant epistasis. Here, dominant allele of one gene can mask the effect of either allele of the second gene.
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8. Name the phenomenon where two genes have the same expression of the character?
a) Pleiotropy
b) Phenocopy
c) Penetrance
d) Expressivity
View Answer

Answer: a
Explanation: Pleiotropy is the condition where either a single gene has multiple functions in the body or two genes have the same expression of the single character.

9. What is psudoallele?
a) Allele with similar function
b) Allele with similar structure
c) Alleles with similar function and structure
d) Alleles with similar function and different structure
View Answer

Answer: d
Explanation: When two types of allele have similar functions but different structures, it is called pseudoallele. These genes located in close proximity.
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10. Name the effect which shows the change in expression of alleles of the gene due to a specific environmental condition.
a) Pleiotropy
b) Linkage
c) Phenocopy
d) Penetrance
View Answer

Answer: c
Explanation: It is a type of phenotypic variation where a single trait of an organism is usually changed due to environmental effects. This is not a hereditary effect when environmental conditions removed it goes back to normal.

Sanfoundry Global Education & Learning Series – Life Sciences.

To practice all areas of Life Sciences, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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