How Genetic disorders arises ? Explain by giving suitable examples.
 

The most important example of point mutation is found in a disease called

Which one of the following symbols and its representation, used in human pedigree analysis is correct ?

$A$ : Sickel cell anaemia occurs due to the point mutation.
$R$ : $mRNA$ produced from $Hb(s)$ gene has $GAG$ instead of $GUG$.