Question

Aneuploidy is caused by __________ of the zygotic chromosome number
A. Thrice of gametic number
B. Twice of gametic number
C. Quadruple of gametic number
D. Abnormality

Answer 1

Aneuploidy is a type of genomic mutation. The genomic mutation is a change in the number of chromosomes. These changes bring out the visible effects on the external features or the phenotype of any organism.

Complete answer:
Aneuploidy is a sort of abnormality of the chromosomal number. During aneuploidy, the change in the chromosome number in any organism is different from the multiple of the basic set of the chromosomes. Aneuploidy usually arises due to the non-disjunction of the homologous chromosomes. Nondisjunction refers to the absence of the separation of homologous chromosomes during cell division. During the non-disjunction, one gamete gets an extra chromosome and the other gamete becomes deficit by one chromosome. When these defected gametes fuse with the normal gametes then aneuploids are formed. Popular examples of genetic disorders that are caused due to aneuploidy are Down’s syndrome, Klinefelter’s syndrome, and Turner’s syndrome. Thus, based on the above information we can conclude that the Aneuploidy is caused by an abnormality of the zygotic chromosome number.
Hence, the correct answer is option (D).

Note: The other type of genomic mutation is the euploidy. The euploidy is the change in the number of chromosomes in the multiples of the haploid sets. It is usually categorized further as haploid or polyploidy. In haploidy, there is one set of chromosomes whereas, in polyploidy, there are more than two sets of chromosomes.