Question

X-rays generally cause

• A. Polyploidy
• B. Frame shift mutations
• C. Chromosomal aberrations
• D. Paramutations

Answer 1

Answer: (C)

Chromosomal aberrations

Frame shift mutation causes forward or backward shifting of reading frame by addition or deletion of bases. Misalignment of a template or progeny strand during DNA synthesis after initiation of DNA replication leads to the addition of base while its misalignment during DNA replication causes deletion of bases, the frame shift mutation.

The presence of more than two haploid chromosomal set causes polyploidy. Chemicals like colchicine disrupt the normal sequence of a nuclear division and induce somatic doubling by inhibiting microtubule formation which in turn prevents the spindle formation and thereby prevents the chromosomes from moving apart during cell division (either mitosis or meiosis). This results in is a cell with doubled chromosome number.

X-rays are ionizing radiations that can penetrate deep within the cell and cause chromosomal aberrations by introducing chromosomal breaks, alteration of nitrogenous bases, or by initiating a chain of chemical reactions. An allelic interaction wherein one allele (para mutagenic) causes a heritable change in the expression of a homologous allele (para mutable allele) is called paramutation. The correct answer is C.