State what are Mendelian disorders. Both thalassemia and colour blindness categorised as Mendelian disorders. Justify.
Mendelian Disorders is a type of genetic disorder occurring due to alterations in one gene or as a result of anomalies in the genome.
Thalassemia:
It is an inherited autosomal recessive disorder which affects the blood. The individuals whose one of the parents is a carrier also become a carrier of the disease. If both the parents are carriers of the disease, the individual has 25% chance of inheriting the disease.
Colour blindness:
It is a genetic disorder which is inherited from the mother. Most of the colour blind people have red or green colour blindness. If the male child inherits this colour blindness from the concerned mother, as he obtains X chromosome from the mother which carries the gene for colour blindness. Hence, the majority of the male will be affected.