Zoology - Principles of Inheritance and Variation Question with Solution | TestHub

The presence of an extra chromosome in diploid chromosome number is called trisomy. It is represented by$(2\mathrm{n}+1).$Here the patient has 47 chromosomes instead of 46. Trisomy of the 21st pair of chromosome- Down's syndrome. Trisomy of the 18th pair of chromosome- Edward's syndrome. Trisomy of the 13th pair of chromosome- Patau syndrome. Klinefelter's syndrome is due to presence of an extra X chromosome in males. The patient's cells contain one additional X chromosome along with XY. Thus their genotype is represented by$(44+\mathrm{X}\mathrm{X}\mathrm{Y})$and they have 47 chromosomes. The absence of a chromosome in diploid chromosome number is called monosomy. It is represented by$(2\mathrm{n}-1)$.Thus they have 45 chromosomes. Turner's syndrome is due to absence of one X chromosome in females. The patient's cells contain only one X chromosome instead of two. Thus their genotype is represented by$(44+\mathrm{X}\mathrm{O})$. Thalassemia is a disorder of genes and not whole chromosomes