Question

1. What type of information does a pedigree contain?

Answer 1

Q1. Pedigree is the recorded lineage of a family. A pedigree chart is actually a diagram showing an appearance and occurrence of phenotypes in several generations. It is used to find a probability of a child inheriting a particular trait or to discover is the trait autosomal or sex-related.

Q2. The presence of a trait in a pedigree chart is shown as filled-in figure. If a square or a circle in the pedigree chart are white (empty), then a person does not have a particular trait. If a figure is filled in (usually black), then a person has a trait. If a figure is half-filled in (e.g. it is half black half white), then a person is only a carrier of a trait but the trait is not expressed.

Q3. In the pedigree charts, squares present males and circles present females. If a female is healthy, the circle is empty (white). If a female is affected with a trait, the circle is filled in (usually black). Similarly, if a male is healthy, the square is empty. If a male is affected with a trait, the square is filled in.

Q4. The presence of dimples is a dominant trait. In dominant traits, traits do not skip generations, unlike recessive traits. From the pedigree, the disorder did not skip any generations. This suggests that the disorder is dominant. If it was recessive, in some generation the trait would not be expressed.

Q5. If a pedigree chart of a family is known, then the occurrence and appearance of a trait can be predicted. For example, if it is known whether a disease is dominant, recessive, or sex-linked, then a possibility of getting a child with a disease can be easily calculated.