Question

What is crossing over

Answer 1

the exchange of genes between homologous chromosomes, resulting in a mixture of parental characteristics in offspring.

Answer 2

ANSWER:-

CROSSING OVER:-

◇ Crossing over is the exchange of segments between the non-sister chromatids of homologous chromosomes.

◇ It occurs during the faculty stage of meiosis and is broken by crossing over.

◇ During zygoten stage, synapsis takes place.

◇ During packetene stage, the chromosomes of each pair splits longitudinally.

◇ Therefore, the segments between non sister chromatids takes place and is referred to as crossing over.

◇ The non sister chromatids remains attatched at the region of crossing over showing a cross-shaped formation.

◇ Two of four chromatids breaks and then rejoin so that the new chromatid formed have exchanged their segments.

◇ The percentage of crossing over depends upon the distance between the genes in chromosome.

◇ If the genes are very close to each other, they show only low percentage of crossing over.

◇ It is a source of genetic variability among sexually reproducing organisms.