If both parents are carriers for thalassaemia, which is an autosomal recessive disorder, what are ch

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4.Principles of Inheritance and Variation

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If both parents are carriers for thalassaemia, which is an autosomal recessive disorder, what are the chances of pregnancy resulting in an affected child?

$0.25$

$1$

No chance

$0.5$

(NEET-2013)

Solution

(a): Thalassaemia is an autosomal recessiveblood disorder. In the given case, both the partners are unaffected carriers for the gene $i.e.$, have heterozygous genotype $Tt$. Persons homozygous for the autosomal recessive gene of $\beta$-thalassaemia suffer from severe haemolytic anaemia. Heterozygous persons are also not normal, but show the defect in a less severe form (thalassaemia minor).

Standard 12

Biology