Question

Exchange of segments between non-sister chromatids of homologous chromosomes is
A. Crossing over
B. Translocation
C. Linkage
D. Inversion

Answer 1

A homologous pair that contains the same genes but different alleles are called the non-sister chromatids. They are not exact copies of each other. This pair of homologous chromosomes is composed of both paternal and a maternal chromosome.

Complete answer:
In this question, we should know that homologous chromosomes have the same gene sequence, gene position, centromere location, and chromosomal length. They may have the same genetic sequence and gene positioning but they may differ in alleles. This pair of homologous chromosomes is composed of both paternal and a maternal chromosome. These chromosomes pair up during meiosis (a division of germ cell) but not during mitosis (a division of stem cell). It happens because as we know meiosis takes place during the fusion of gametes and offspring receives chromosomes from both father and mother.

Translocation is the chromosome abnormality caused by the rearrangement of parts between nonhomologous chromosomes. In this process, a segment from one chromosome is exchanged with the segment of another non-homologous chromosome. Translocation takes place because:
Change aroused during the making of the egg or the sperm or around the time of conception
Chromosomes inherited from either mother or father have an altered chromosome arrangement.

A chromosomal arrangement called inversion, this part of a chromosome is an end to end inversion, and this inversion takes place when a single chromosome undergoes breakage and rearrangement within itself.
Crossing over is the process in which the exchange of genetic material occurs between non sister chromatids of homologous chromosomes during meiosis and results in a new allelic combination of the daughter cell.
Linkage is the close association of genes or DNA sequences on the same chromosome.

Hence, the correct answer is option (A)

Note: Crossing over is the process in which the exchange of genetic material occurs between non-sister chromatids of homologous chromosomes during meiosis and results in a new allelic combination of the daughter cell. These chromosomes pair up during meiosis (a division of germ cell) but not during mitosis (a division of stem cell). It happens because as we know meiosis takes place during the fusion of gametes and offspring receives chromosomes from both father and mother.