Question

Euploidy is best explained by
(A) One chromosome less than the haploid set of chromosomes
(B) Exact multiples of a haploid set of chromosomes
(C) One chromosome more than the haploid set of chromosomes
(D) One chromosome more than the diploid set of chromosomes

Answer 1

Hint: Euploidy is a result of mutation. Mutation can be best described as a sudden heritable change in the genetic material of an organism. Mutations are of two types i.e 1) Chromosomal mutation 1) Gene Mutation.

Complete answer:
Chromosomal Mutation is the change in the number or structure of the chromosome.
There are two types of chromosomal mutation that are Heteroploidy or Genomic mutation and Chromosomal aberration.
Genomic mutation is characterized as a change in one or a few chromosomes in a set of chromosomes. Euploidy and aneuploidy are the two examples of genomic mutation.
Euploidy is basically a change in a number of sets of chromosomes i.e. either addition or loss of sets of chromosomes. It can also be described as the availability of a complete set of haploid chromosomes. The presence of haploid chromosome sets is multiple. Euploidy consists of Monoploidy, diploidy, and polyploidy.
Monoploidy is the presence of one set of chromosomes.
Diploidy is the presence of two sets of chromosomes.
Polyploidy is more than two sets of chromosomes.

Therefore, the correct option is (B) Exact multiples of a haploid set of chromosomes.

Note:
 The second type of Heteroploidy is Aneuploidy that can be described as a change in a number of chromosomes in a set i.e. loss or addition of chromosomes in a set of chromosomes. Types of Aneuploidy are Hypo Aneuploidy and Hyper Aneuploidy. The reason behind aneuploidy is chromosomal nondisjunction i.e. during meiosis, chromosomes fail to separate. It is observed that higher age females are at more risk of Aneuploidy.