Question

Which one of the following symbols and its representation used in human pedigree analysis is correct
A.

= unaffected man
B.

= unaffected female
C.

= male affected
D.

= mating between relatives

Answer 1

Hint: Pedigree analysis shows the phenotypes and/or genotypes for a particular organism and its ancestors.

Complete answer:
A pedigree analysis is drawn when trying to determine the nature of a newly discovered disease, or when an individual with a family history of a disease wants to know the probability of passing the disease on to their children.
In pedigree analysis uncolored circle means unaffected female, square means unaffected male, and a diamond means sex unknown.
In pedigree analysis colored circle means affected female, square means affected male, and a diamond means affected sex unknown.
In pedigree analysis a square joined with a circle by a single line means marriage whereas a square joined by two lines with a circle means mating between relatives (consanguineous marriage).

So, the answer is option D.

Additional information:
-Mating between males and females is shown by a horizontal line between their respective symbols. This line is then attached to another horizontal line below, which is joined to the symbols for their offspring.
- Siblings are depicted from left to right in the order in which they were born. The eldest sibling is shown to the far left and the youngest to the far right.
-Numbers are frequently used in pedigrees to indicate individuals or generations. Generations are shown in Roman numerals and individuals are shown in Arabic numerals.
 All individuals are numbered from left to right in a pedigree.

Note:
Careful pedigree analysis can identify relatives who may be at risk of inheriting the disease and for whom clinical screening with electrocardiography and echocardiography may be appropriate after counseling.