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प्रश्न
Identify chromosomal disorder caused due to non-disjunction of the 21st number of chromosomes and enlist its symptoms.
Identify chromosomal disorder caused due to non-disjunction of 21% chromosome and enlist its characteristics.
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उत्तर
Down syndrome is usually caused by an error in cell division called non-disjunction. Non-disjunction results in an embryo with three copies of chromosome 21 instead of the usual two.
Common Symptoms (Characteristics) of Down syndrome are:
- Mild or moderate mental retardation and poor skeletal development.
- Distinct facial features like small head, ears and mouth.
- Eyes slant up and out with internal epicanthal folds.
संबंधित प्रश्न
Why is pedigree analysis done in the study of human genetics? State the conclusions that can be drawn from it.
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 |
A male rabbit of genotype 'AABBDDEE' is crossed with a female rabbit of genotype 'aabbddee' to produce F1 hybrid offspring. How many genetically different gametes can be produced by this F1 hybrid?
Identify the disease caused by an autosomal primary non-disjunction.
In Klinefelter syndrome, an extra chromosome is a result of non-disjunction of X-chromosome during ____________.
Genes for cytoplasmic male sterility in plants are generally located in ______.
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 ______.
Down’s syndrome is due to ______.
Fused ear lobes appear in the progeny due to an autosomal recessive gene. Work out the genotypes of number in the given pedigree.
