In Eukaryotes, there are two connected processes called crossing over and genetic linkage. Crossing over happens when genetic material swaps in the germline, while genetic linkage refers to genes staying close together on a chromosome.
Linkage And Crossing Over MCQ for NEET
Ques 1. If the percentage of crossing over between two genes is 10, then the distance between two genes will be
1. 40 map units
2. 10 centimorgans
3. 20 centimorgans
4. 5 morganoid
Answer: 10 centimorgans
Ques 2. Repulsion and coupling are two faces of
1. mutation
2. crossing over
3. linkage
4. chiasmata
Answer: linkage
Ques 3. Percentage of crossing over is more when
1. inked genes are located close to each other
2. genes are not linked
3. genes are located in a different cell
4. linked genes are located far apart from each other
Answer: linked genes are located far apart from each other
Ques 4. Crossing over takes place in the
1. Pachytene stage
2. Anaphase stage
3. Diakinesis stage
4. Leptotene stage
Answer: Pachytene stage
Ques 5. This is the reason why Mendel did not recognize linkage phenomenon in his experiments
1. he studied only pure plants
2. many chromosomes to handle
3. characters he studied were situated on different chromosomes
4. he did not have a powerful microscope
Answer: characters he studied were situated on different chromosomes
Ques 6. There are 4 pairs of chromosomes in a Drosophila. The linkage groups present in it are
1. four
2. one less than the pair of chromosomes
3. one more than the pair of chromosomes
4. eight
Answer: four
Ques 7. Crossing over occurs between
1. Non-sister chromatids of non-homologous chromosome at zygotene stage of prophase-I
2. Non-sister chromatids of homologous chromosome at zygotene stage of prophase I
3. Non-sister chromatids of non-homologous chromosomes at pachytene stage of prophase I
4. Non-sister chromatids of homologous chromosome at pachytene stage of prophase-I
Answer: Non-sister chromatids of homologous chromosome at pachytene stage of prophase-I
Ques 8. Alleles of different genes that are on the same chromosome can occasionally be separated by a phenomenon called
1. crossing over
2. epistasis
3. continuous variation
4. pleiotropy
Answer: crossing over
Ques 9. Where does this evidence come from? – crossing over takes place at a four-stranded stage and not at two stranded stages of chromosomes.
1. studies on linkage maps of chromosomes in Drosophila
2. 2:2:2:2 organization of ascospores in Neurospora
3. 4:4 organization of ascospores in Neurospora
4. studies of meiosis in maize
Answer: 2:2:2:2 organization of ascospores in Neurospora
Ques 10. In a linear chromosome map distance between 4 loci is as follows a-b is 10%, a-d is 3%, b-c is 4% and a-c is 6%. The crossover frequency between c and d is
1. 4-12%
2. 9%
3. 3-6%
4. 3%
Answer: 3%
Ques 11. If gene frequency between genes a and c is 2%; b and c is 13%; b and d 4%; a and b 15%; c and d 17 and a and d 19%. The sequence of genes in a chromosome is
1. a,d,b,c
2. a,c,b,d
3. a,b,c,d
4. d,b,a,c
Answer: a,c,b,d
