Pedigree Analysis is a tabular representation of a family history by taking a particular disease or character into consideration.
Proband or Propositus is an individual from which a pedigree is initiated.
Female are represented in circles.
Male are represented in squares.
Individuals carrying the character to be studied are shaded. or
It helps us to find out whether the gene is dominant or recessive and autosomal or sex-linked. And the chances of expressing itself in the coming generations.
In the case of autosomal genes:
- It equally affects both males and females.
In the case of sex-linked genes:
- Affects the males as they are hemizygous.
- The gene shows criss-cross inheritance i.e., the gene from the father is transferred to the grandson through the daughters.
- In the case of a sex-linked dominant gene, more females are affected than males.
- Never transferred from father to son.