Question

Given in the figure is chromosome mutation. It is

• A. Duplication
• B. Inversion
• C. Deletion
• D. Reciprocal translocation

Answer 1

Answer: (B)

Inversion

Inversion is chromosomal mutation where a segment of a chromosome is reversed end to end. It occurs by introduction of a break in a single chromosome, its rotation by l80${}^o$ followed by its reinsertion in the same location. Loss of one or more nucleotide bases to the DNA segment by removal of an intercalary DNA segment is known as deletion. Duplication is the presence of extra-chromosomal segment which is attached to the normal homologous chromosome causing duplication of the set of genes in the same chromosome. Exchange of chromosomal segment between two nonhomologous chromosomes is called as reciprocal translocation. In the given image, A”BCD”EFGH is mutated to A”DCB”EFGH which means that segment “BCD” is inverted to “DCB”. There is no duplication, deletion or exchange of segments but the intercalary segment “BCD” is rotated to 180${}^o$. The correct option is B.