Study the human pedigree chart given below and choose the correct conclusion.
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Parents with male child affected with disease
A pedigree chart follows a trait through the members of one family. A square is a male, a circle is a female, and a marked (filled) symbol is an affected person. A horizontal line joins the parents, and a vertical line leads down to their child.
Option (1) Parents with male child affected with disease — Correct. The child is a square, so a son, and he alone is marked in red as affected. Parents who do not show a trait but have an affected child must carry the allele without showing it.
Option (2) Parents with female child affected with disease — Incorrect. The child’s symbol is a square, which stands for a male.
Option (3) Normal male child with disease affected parents — Incorrect. It is the other way round. The child is the one marked affected.
Option (4) Parents with normal male child — Incorrect. The son is marked as affected, so he is not normal.