Crossing over is an important phenomena during meiosis. In this presentation I'm trying to explain crossing over with pictures.

1. Crossing Over
Presented by:
Sanjay Kr. Vishwakarma

2. Crossing Over
• Discovered by T. H. Morgan
• Recombination of genes on the same chromosome
• Parts of homologous chromosomes interchanged

3. Crossing Over

4. Crossing Over

5. Crossing Over
• Occurs during Meiosis-I
• Crossing over occur in mitotic division cause Loss of heterozygosity
• Loss of heterozygosity (LOH) is a gross chromosome even that
results in loss of the entire gene and the surrounding chromosomal
region

6. Crossing Over
• Crossing over is essential for normal segregation of chromosomes
during meiosis.
• Crossing over also accounts for genetic variation because due to the
swapping (to exchange something for another) of genetic materials
during crossing over.

7. Percentage of Crossing Over
• The percentage of crossing over is directly proportional to the distance between two genes
• Unit of distance between genes is centimorgan (cM)

8. Multiple Choice Question

9. 1) Percentage of crossing over is more when
a) Genes are located in a different cell
b) Genes are not linked
c) Linked genes are located close to each other
d) Linked genes are located far apart from each other
Answer: d

10. 2) If the percentage of crossing over between two genes is 10, then the distance between two
genes will be
a) 5 centimorgans
b) 10 centimorgans
c) 20 centimorgans
d) 40 map units
Answer: b

11. 3) Alleles of different genes that are on the same chromosome may occasionally be separated
by a phenomenon known as
a) Pleiotropy
b) Epistasis
c) Continuous variation
d) Crossing over
Answer: d

12. 4) Crossing over in diploid organism is responsible for
a) Dominance of gene
b) Linkage between genes
c) Recombination of linked allele
d) Segregation of alleles
Answer: c

13. Thank You