Biology - Principles of Inheritance and Variation Question with Solution | TestHub

Hypertrichosis pinnae, which refers to the presence of excessive hair on the external ear or pinna, is a classic example of a trait controlled by genes located on the non-homologous segment of the Y chromosome.

Traits determined by genes located on the Y chromosome are known as Y-linked or holandric traits.

Since females possess two X chromosomes ($XX$) and males possess one X and one Y chromosome ($XY$), Y-linked traits are exclusively transmitted from an affected father to all of his sons.

Therefore, hypertrichosis is a Y-linked character.

Answer: Y - linked