Question

What is correct?
A. Monosomy and nullisomy are two types of euploidy
B. Polyploidy is more common in animals than in plants
C. Polyploids occur due to failure in separation of complete sets of chromosomes
D. 2n-1 is trisomy
E. Nonhomologous chromosome duplication produces autopolyploidy

Answer 1

Mutation is defined as sudden, discontinuous variation in genotype and phenotype of an organism due to change in chromosomes and genes. In addition to recombination, mutation is another phenomenon that leads to variation in DNA.

Complete Answer:
Now let us discuss about every option step by step
- Monosomy and nullisomy are two types of euploidy: These two are types of Aneuploidy. In aneuploidy, any change in the number of chromosomes in an organism would be different from the multiple of the basic set of chromosomes. It commonly arises due to nondisjunction (absence of separation of two homologous chromosomes during cell division) of the two chromosomes of homologous pair so that one gamete comes to have an extra chromosome (n +1) while the other becomes deficient in one chromosome (n-1).
- Polyploidy is more common in animals than in plants: It is often seen in plants. In the case of animals, polyploidy usually results in sterility. Therefore, polyploidy is rare in animals. Polyploidy falls into two major categories: autopolyploidy and allopolyploidy.
- Polyploids occur due to failure in separation of complete sets of chromosomes: Polyploidy is defined as More than two sets of chromosomes. Failure of cytokinesis after the telophase stage of cell division results in an increase in a whole set of chromosomes in an organism and this phenomenon is called polyploidy.
- 2n-1 is trisomy: Trisomy is a kind of Aneuploidy. It occurs due to the condition of 2n+1. Down’s syndrome is a kind of trisomy.
- Nonhomologous chromosome duplication produces autopolyploidy: Autopolyploid results due to presence of multiple sets of chromosomes.

Our required option is C that is Polyploidy occurs due to failure in separation of complete sets of chromosomes.

Note: The most common type of mutation, is the change from normal or wild type to new genotype (recessive or dominant). Such mutations are called forward mutations. An organism which has undergone forward mutation, may again develop mutation which restores the original wild-type phenotype. Such reversions are known as backward mutations or reverse mutations.