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Principles of Inheritance and Variation — BIOLOGY STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceBIOLOGYPrinciples of Inheritance and Variation4 Marks
Question
How are genetic disorders broadly classified? Differentiate between them. Explain by giving one example for each.
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Answer

These are disorders or illness caused by one or more abnormlities in the autosomes or sex chromosomes of the person. Thus, referred to as autosomal disorders or sex-linked disorders, respectively.
The generic disorders are divided into:

Differentiate between Mendelian and Chormosomal disorders are:
S.No.
Mendelian disorders
Chormosomal disorders
(i)
The disorders are caused by allelic abnormalities.
The disorders are caused by chromosomal abnormalities
(ii) 
Allelic abnormalities develop due to mutations.
Chromosomal abnormalities develop due to defective synapsis and disjunction.
(iii)
The defect can be predicted through pedigree analysis.
The defect can be known through amniocentesis.
(iv)
The disorder is transmitted to the progeny.
The disorder is rarely transmitted.
(v) 
Examples: Haemophilia, Cystic fibrosis, Colour blindness, Sickle-cell anaemia, Thalassemia, Phenylketonuria, etc.
Examples: Down's syndrome, Turner's syndrome, Klinefelter's syndrome, etc.

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