Practicing Success

Target Exam

CUET

Subject

Biology

Chapter

Principles of Inheritance and Variation

Question:

Read the passage and answer the following questions :
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, Sicklecell anaemia, Colour blindness, Phenylketonuria, Thalassemia, etc. It is important to mention here that such Mendelian disorders may be dominant or recessive. Thalassemia : This is also an autosome-linked recessive blood disease transmitted from parents to the offspring when both the partners are unaffected carrier for the gene (or heterozygous). The defect could be due to either mutation or deletion which ultimately results in reduced rate of synthesis of one of the globin chains (α and β chains) that make up haemoglobin.

Which among the following is a an autosome-linked disease ?

Options:

Sickle-cell anaemia .

Klinefelter’s Syndrome .

Thalassemia .

Both 1 and 3 .

Correct Answer:

Both 1 and 3 .

Explanation:

The correct answer is Option (4) –Both 1 and 3.

Sickle-cell anemia and thalassemia are autosomal recessive disorders, while Klinefelter's syndrome is a chromosomal disorder caused by the presence of an extra X chromosome in males (XXY).

Thalassemia is an autosome-linked recessive blood disease .Sickle-cell anaemia is also an autosome linked recessive trait . Most common and prevalent Mendelian disorders are Haemophilia, Cystic fibrosis, Sicklecell anaemia, Colour blindness, Phenylketonuria, Thalassemia, etc.

Therefore, the correct answer is option (4) - Both 1 (Sickle-cell anemia) and 3 (Thalassemia).