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Question
Write a note on Down’s syndrome.
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Solution
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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RELATED QUESTIONS
Why is pedigree analysis done in the study of human genetics? State the conclusions that can be drawn from it.
The genotype of a person withTumer's syndrome will be:
(i) 44+XXY
(ii) 44+XYY
(iii) 44+XO
(iv) 44+XXYY
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 |
Webbed neck is characteristic of ______ syndrome.
Identify the INCORRECT statement.
Read the following and answer from given below:
Turner's syndrome is an example of monosomy. It is formed by the union of an allosome-free egg and a normal 'X' containing sperm or a normal egg and an allosome-free sperm. The individual has 2n = 45 chromosomes (44 + X0) instead of 46. Such individuals are sterile females who have rudimentary ovaries, underdeveloped breasts, small uterus, short stature, webbed neck, and abnormal intelligence. They may not menstruate or ovulate. This disorder can be treated by giving female sex hormones to women from the age of puberty to make them develop breasts and have menstruation. This makes them feel more normal.
The number of Barr bodies present in a female with Turner's syndrome is ______
Read the following and answer from given below:
Turner's syndrome is an example of monosomy. It is formed by the union of an allosome-free egg and a normal 'X' containing sperm or a normal egg and an allosome-free sperm. The individual has 2n = 45 chromosomes (44 + X0) instead of 46. Such individuals are sterile females who have rudimentary ovaries, underdeveloped breasts, small uterus, short stature, webbed neck, and abnormal intelligence. They may not menstruate or ovulate. This disorder can be treated by giving female sex hormones to women from the age of puberty to make them develop breasts and have menstruation. This makes them feel more normal.
Turner's syndrome is a/an ______
Identify chromosomal disorder caused due to non-disjunction of the 21st number of chromosomes and enlist its symptoms.
Describe Klinefelter’s syndrome.
Match the disorder in column I with their nature in column II.
| Column I | Column II | ||
| i. | Thalassemia | a. | X monosomy |
| ii. | Turner’s syndrome | b. | Extra X chromosomes in male |
| iii. | Klinefelter’s syndrome | c. | 21st Trisomy |
| iv. | Down’s syndrome | d. | Mendelian disorder |
