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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
Very Short Answer Question.
Give an example of a chromosomal disorder caused due to nondisjunction of autosomes.
Read the following statements and select the correct option.
i. Genetic disorders are broadly categorised as, Mendelian disorders and chromosomal disorders.
ii. Mendelian disorders are caused due to absence or excess of one or more chromosomes or their abnormal arrangement.
iii. Chromosomal disorders are mainly caused due to alteration or mutation in the gene.
Following list indicates various genetic diseases. Identify the diseases that are not caused due to single gene defect.
Huntington's chorea, alkaptonuria, Sickle cell anaemia, Down syndrome, thalassemia, Taysachs disease, Turner syndrome, cystic fibrosis, haemophi Lia, Klinefelter syndrome, albinism
Conditions of a karyotype 2n ± 1 and 2n ± 2 are called ______.
Sickle cell anaemia is ______.
This abnormality occurs due to monosomy (2n - 1); the individual has 2n = 45 chromosomes with 44 + XO genotype.
Read the following and answer from given below:
According to Mendel, one gene controls the expression of one character only. The ability of a gene to have multiple phenotypic effects because it influences a number of characters are an exception. The gene has multiple phenotypic effects because its ability to control two or more characters can be seen in cotton. In cotton, a gene for the lint also influences the height of the plant, size of the ball, number of ovules, and viability of seeds.
Which of the following disorder is an example of genes with multiple phenotypic effects?
Clotting of blood is to ______.
Short stature in females, webbed neck absence of menstrual cycle and sterility are characteristics which of the following disease?
Give definition of non-disjunction.
