Explain with an example how single genes affect multiple traits and alleles the phenotype of an organism.

Explanation

In Pleiotropy , the single gene affects multiple traits and alter phenotype of the organism. The Pleiotropic gene influences a number of characters simultaneously and such genes are called pleiotropic gene . Mendel noticed plecitropy while performing breeding experiment with peas (Pisum sativum) . Peas with purple flowers , brown seeds and dark spot on the axils of the leaves were crossed with a a variety of peas having white flowers , light coloured seeds and no spot on the axils of the leaves , the three traits for flowers colour , seed colour and a leaf axial spot all were inherited together as a single unit . This is due to the patterm of inheritance where the three traits were controlled by a single gene with dominant and recessive alleles.
Example : sickle cell anemia.