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प्रश्न
Write a note on Down’s syndrome.
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उत्तर
Down syndrome:
- Individuals suffering from Down syndrome will have 47 chromosomes instead of the normal number 46.
- 21st Trisomy occurs due to non-disjunction or failure of separation of chromosomes (autosomes) during gamete formation.
- Following are the symptoms of Down syndrome:
- Mild or moderate mental retardation and poor skeletal development.
- Distinct facial features like small head, ears, and mouth.
- The face is typically flat and rounded with a flat nose, open mouth, and protruding tongue.
- Eyes slant up and out with internal epicanthal folds.
- Flat hands and stubby fingers, the palm is broad with a single palmer crease.
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संबंधित प्रश्न
Why is pedigree analysis done in the study of human genetics? State the conclusions that can be drawn from it.
Name the disorder caused by under secretion of thyroxine in children
State any two symptoms of Down’s syndrome.
Match the column-I with column-II and re-write the matching pairs.
| Column-I | Column-II |
| 1. 21 trisomy | a. Turner’s syndrome |
| 2. X-monosomy | b. Klinefelter’s syndrome |
| 3. Holandric traits | c. Down's syndrome |
| 4. Feminized male | d. Hypertrichosis |
Match the Column-I with Column-II and choose the CORRECT answer
| Column-I | Column-II | ||
| P. | Klinefelter syndrome | i. | Mutation in autosomal gene |
| Q. | Thalassaemia | ii. | Mutation sex chromosome linked gene |
| R. | Down syndrome | iii. | Trisomy of autosome |
| S. | Colour blindness | iv. | Trisomy of sex chromosome |
It is well known that Queen Victoria of England was a carrier for haemophilia. Since this is an X-linked disease, it can be predicted that ______.
Select the incorrect statement regarding pedigree analysis.
Trisomy is represented by ______.
Rajesh and Mahesh have defective haemoglobin due to genetic disorders. Rajesh has too few globin molecules while Mahesh has incorrectly functioning globin molecules. Identify the disorder they are suffering from.
| Rajesh | Mahesh | |
| A. | Sickle cell anaemia - an autosome linked recessive trait | Thalassemia - an autosome linked dominant trait |
| B. | Thalassemia - an autosome linked recessive blood disorder | Sickle cell anaemia - an autosome linked recessive trait |
| C. | Sickle cell anemia - an autosome linked recessive trait | Thalassemia - an autosome linked recessive blood disorder |
| D. | Thalassemia - an autosome linked recessive blood disorder | Sickle cell anaemia - an autosome linked dominant trait |
Describe Klinefelter’s syndrome.
