write the cytological basis of crossing over?
Answers
2. Crossing Over • Crossing over is a process that produces new combinations of genes by exchanging segments between non-sister chromatids of homologous chromosomes normally reciprocally but sometimes unequally. • Crossovers are chromatins resulting from crossing over i.e. interchange of chromosomal parts. • The term crossing over was coined by Morgan.
3. Characteristics of Crossing Over • Occurs at two levels, at gross chromosomal level (chromosomal recombination) and at DNA level (genetic recombination). • Occurs between non-sister chromatids of homologous chromosomes. • Exchange is normally reciprocal but sometimes unequal. • Frequency of crossing over is closely related to physical distance between genes located on chromosomes.
In 1931, 'Harriet Creighton' and 'Barbara McClintock' demonstrated the physical basis of crossing over for the first.
EXPLANATION:
Crossing over is the process which occurs in meiotic cells of bisexual reproduction. This process enable the genetic material to be passed to next generation through the sexual gametes that form at the end of the meiosis II division. This process happen between 'non- sister chromatids of homologous chromosomes' normally, reciprocally and also sometimes unequally.