Match the LIST-I with LIST-II
| LIST-I | LIST-II | ||
|---|---|---|---|
| Genetic disorders | Features | ||
| A. | Down’s syndrome | I. | Additional copy of the X chromosome |
| B. | Klinefelter’s syndrome | II. | Absence of one X chromosome |
| C. | Turner’s syndrome | III. | Autosomal linked recessive disorder |
| D. | Sickle-cell anaemia | IV. | Trisomy of chromosome 21 |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → A-IV, B-I, C-II, D-III
(A) Down’s syndrome — this matches (IV) Trisomy of chromosome 21. The person has three copies of chromosome 21, so the total is 47. It is caused by non-disjunction of chromosome 21 during gamete formation.
(B) Klinefelter’s syndrome — this matches (I) Additional copy of the X chromosome. The person has the karyotype XXY, so the total is 47. The person is male in looks but has some female features and is sterile.
(C) Turner’s syndrome — this matches (II) Absence of one X chromosome. The person has the karyotype XO, so the total is 45. The person is a sterile female with poorly developed ovaries.
(D) Sickle-cell anaemia — this matches (III) Autosomal linked recessive disorder. A single base change in the gene for the beta chain of haemoglobin, which is on an autosome, causes it. The disease shows only when both copies of the gene are changed.