Question

Draw the pedigree for the question below, take a picture or a scan, and upload it here.

Text of the question: Defects on the SOX21 gene are suspected to be Y-linked and to cause baldness in men. A bald man and woman with normal hair have two sons and two daughters, and both sons are bald. The two daughters have each two sons, and none are bald. The man's sons also have two sons each, and all four are bald. Draw a pedigree for this family using standard symbols.

Answer 1

Genetic disorder

Genetic disorders are otherwise called inherited disorders as it passes on to generations.  Inheritance can be either

1. Autosomal type of inheritance

2. Sex linked inheritance

• X linked : mutated gene present in the X chromosome
• Y linked: mutation present in the Y chromosome

*It can be also classified as Dominant type or recessive type

Y linked inheritance: Sex chromosome are responsible for determining the sex of an individual females have two homologous X chromosome, whereas males have one X and one Y chromosome.

• Males pass Y chromosome to their sons  and X chromosome to their daughter.
• Therefore any defect in the Y chromosome will be transferred to their male offspring and passes through generations. Female offspring will remain unaffected as they don’t gave Y chromosome.

Here in the pedigree defective Y gene is passed on from the First generation make to his sons in the second generation and from them to the third generation.