Which of the following statement is correct about incomplete linkage?(...
Linkage means the tight bond of chromosomes to each other. where there is tight linkage there is less recombination.
Which of the following statement is correct about incomplete linkage?(...
Incomplete linkage refers to the phenomenon where two genes located on the same chromosome are not completely linked and occasionally undergo crossing over. The correct statement about incomplete linkage is:
(i) It is a phenomenon in which more recombinants are produced in the F2 generation.
Explanation:
- Incomplete linkage occurs when two genes are located on the same chromosome but are not very close together.
- During meiosis, crossing over may occur between these two genes, leading to the exchange of genetic material between homologous chromosomes.
- This crossing over results in the formation of recombinant chromosomes, which carry a combination of alleles different from the parental chromosomes.
- In the F1 generation, the parents are heterozygous for both genes, and during meiosis, crossing over can occur between the two genes on the homologous chromosomes.
- However, the frequency of crossing over is low due to the distance between the genes.
- In the F2 generation, the recombinant chromosomes produced during crossing over can result in more recombinant offspring.
- Therefore, more recombinants are observed in the F2 generation in the case of incomplete linkage.
The other statements are incorrect:
(ii) More parental combinations are produced in the F1 generation: This statement is incorrect because in the F1 generation, there is no crossing over occurring between the genes as the parents are heterozygous for both genes.
(iii) Genotypes which are present in hybrid reappear in high frequency in the F2 generation: This statement is incorrect because incomplete linkage leads to the formation of new combinations of alleles, resulting in recombinants, rather than the reappearance of the same genotypes from the hybrid.
(iv) It is a phenomenon in which two chromosomes are linked: This statement is incorrect because incomplete linkage refers to the situation where two genes on the same chromosome are not completely linked and can undergo crossing over. It does not involve two separate chromosomes.