Describe Mendelian disorders.

(N/A) Mendelian disorders are primarily determined by alterations or mutations in a single gene.
These disorders are transmitted to the offspring following the principles of inheritance.
The pattern of inheritance of Mendelian disorders can be traced in a family through pedigree analysis.
Some common and prevalent Mendelian disorders include Haemophilia,Cystic fibrosis,Sickle cell anaemia,Colour blindness,Phenylketonuria,and Thalassemia.
Such Mendelian disorders may be dominant or recessive.
Through pedigree analysis,one can easily determine whether the trait in question is dominant or recessive.
Similarly,the trait may also be linked to the sex chromosome,as in the case of haemophilia.
It is evident that this $X$-linked recessive trait shows transmission from a carrier female to male progeny.
$A$ representative pedigree is shown in the figure for dominant and recessive traits.
Colour blindness is a sex-linked recessive disorder caused by a defect in either the red or green cones of the eye,resulting in a failure to discriminate between red and green colours.