Why do linked genes show a lesser inclination towards crossing over than incompletely linked ones?
1 Answer
It is because of the fact that the distance between the loci of linked genes is much shorter than that between incompletely linked genes.
Explanation:
Crossing over occurs between two homologous chromosomes during prophase stage of meisosis-I.
The frequency of crossing over is directly proportional to the distance between the loci of two genes. The position of genes also affects the occurrence of crossing over.
Thus the genes which are very close to each other will always be linked as there is no possibility of crossing over to occur.
The genes which are very far apart from each other or present on other side of the centromere will not show any linkage and will seggregate independently of each other.
The genes which are neither very close nor very far apart from each other will show incomplete linkage as the frequencey of crossing over will vary between the relative distance between the loci of two genes.
Thus the inclination of two genes towards crossing over depends upon the distance between the loci of two genes as explained above.
