Question

Which of the following processes are responsible for creating new combinations of genes on chromosomes?

• A. Nucleotide deletion
• B. Independent assortment
• C. Segregation
• D. Crossing over
• E. Base pair substitution

Answer 1

The correct option is D Crossing over

A. Nucleotide deletion is the loss of nucleotides from a DNA segment which results in change in sequence of DNA and may cause frameshift mutation.

B. The principle of independent assortment was stated by Mendel, according to which, if the inheritance of more than one character is studied simultaneously, the factors or genes for each character assort out independently to the other gene or factor.

C. Segregation is the separation of dominant and recessive characters at the time of gametogenesis or gamete formation.

D. Crossing over is a process that produces new combination of genes by interchanging of segments between non-sister chromatids of homologous chromosomes. It occurs during pachytene of prophase I of meiosis I.

E. Base pair substitution is a type of mutation in which one nitrogenous base is substituted by other. It can be transition, if a purine base is replaced by another purine base or transversion, if a purine base is replaced by a pyrimidine base or vice versa.

So, the correct answer is 'Crossing over'.