Question

Among the given options, which criteria must a genetic disorder qualify to be classified as a Mendelian disorder?

• A. Mutation in a single gene
• B. Mutation in an entire chromosome
• C. Mutation in germplasm
• D. Mutation in genome

Answer 1

The correct option is A Mutation in a single gene

Any disease or disorder caused due to changes in the genetic material (DNA in case of humans), which can be passed down to the subsequent generations, is known as genetic disease or genetic disorders.
Genetic disorders can be divided into two types- based on whether the changes have occurred in a gene (Mendelian disorders) or in the chromosomes (chromosomal disorders).
Mendelian disorders are mainly determined by alteration or mutation of a single gene. Mendelian disorders obey the laws of Mendel, such as the law of dominance and segregation.
Mutations are sudden changes in the genetic material of the organisms which can be caused due to various reasons and can be passed down to the next generation. If mutation occurs in an entire chromosome, it would be considered a chromosomal disorder.
Germplasm is a collective term used to refer to the genetic material of an organism. Genome refers to the complete set of chromosomes of an organism. Mutations in the germplasm or genome cannot be considered as Mendelian disorders as Mendel’s laws are not applicable to the entire germplasm or genome.