A mutation is a change in the DNA of an organism. The change may or may not result in a change to the physical characteristics (or phenotype) of the organism. Mutations that occur in a gamete (sperm or eggs) can be passed to the next generation, whereas mutations that occur in body (or 'somatic') cells may be harmless or may result in a disease such as cancer. Mutations can result in DNA being copied incorrectly. Mutagens can also cause mutations.
A point mutation is a change in one base in the genetic code. The change of one base to a different base (often caused by the DNA being copied incorrectly)-this is called a substitution mutation.
Identify the inheritable disorders caused by mutation of genes in human beings:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Sickle Cell Anaemia and Thalassemia
Option (2) Sickle Cell Anaemia and Thalassemia — Correct. Both sickle-cell anaemia and thalassemia are Mendelian disorders: each is caused by a mutation in a single gene (the globin genes) and is inherited by the principles of inheritance.
NCERT Extract:
Mendelian Disorders – “Broadly, genetic disorders may be grouped into two categories – Mendelian disorders and Chromosomal disorders. Mendelian disorders are mainly determined by alteration or mutation in the single gene. These disorders are transmitted to the offspring on the same lines as we have studied in the principle of inheritance. The pattern of inheritance of such Mendelian disorders can be traced in a family by the pedigree analysis. Most common and prevalent Mendelian disorders are Haemophilia, Cystic fibrosis, Sickle-cell anaemia, Colour blindness, Phenylketonuria, Thalassemia, etc.”