if genes are specific parts of dna helix then how can we explain recombination and linkage? is this that  a part of dna is breaked from onechromosome and joinedon other???????

Asked by upmaniousagarika | 25th Jun, 2016, 06:01: PM

Expert Answer:

All the genes located in the same chromosome behave as a unit during meiosis and are inherited together. These genes do not follow independent assortment and stay together during inheritance through generations without any change or separation. This phenomenon of inheritance of genes together and retain parental combination in the offspring is known as linkage.

Recombination occurs when two molecules of DNA exchange pieces of their genetic material with each other. This process is called crossing over. Crossing over is the physical process of reciprocal exchange of corresponding parts between the chromatids of homologous chromosomes of a pair that results in the new combinations of alleles of the linked genes.

Genetic recombination is a complex process that involves alignment of two homologous DNA strands, precise breakage of each strand, equal exchange of DNA segments between the two strands, and sealing of the resultant recombined DNA molecules through the action of enzymes called ligases.

Answered by Sheetal Kolte | 27th Jun, 2016, 11:55: AM