Question
Biology Question on Principles of Inheritance and Variation
Pattern baldness, moustaches and beard in human males are examples of
Sex-linked traits
Sex limited traits
Sex influenced traits
Sex determining traits
Sex limited traits
Solution
Sex linked traits are the one whose governing genes are present on the sex chromosomes and are transmitted from parent to progeny through sex chromosomes only. Example is haemophilia. Sex-determining traits are the one that initiate male or female sex development pattern in the developing embryo. It considers the presence and type of sex chromosomes. For example, presence of two X-chromosome determines the female sex in human. The primary and secondary sex characters are sex differentiating traits as they differentiates between two sex. It includes sex-linked, sex influenced and sex-limited traits. Pattern baldness, moustaches and beard in human males are examples of sex-limited traits. Androgenic hormones should be present in certain levels for the governing dominant genes to be expressed. These androgenic hormones never attain the required level in females and therefore, these genes are never expressed in females.