Moles occur when cells in the skin grow in a cluster instead of being spread throughout the skin. These cells are called melanocytes, and they make the pigment that gives skin its natural color. Moles may darken after exposure to the sun, during the teen years, and during pregnancy.
A pedigree chart is used to show your family tree of traits. An example is if a diagram shows your mom who had brown hair and your dad has red hair and then it shows all of th â¦ e children they had and shows what color hair they had.
In single-gene diseases, a mutation in just one of these genes is responsible for disease. Single-gene diseases run in families and can be dominant or recessive, and autosomal or sex-linked.Pedigree analyses of large families with many affected members are very useful for determining the inheritance pattern of single-gene diseases. Table 1 includes some examples of single-gene diseases.ingle-gene diseases run in families and can be dominant or recessive, and autosomal or sex-linked. Pedigree analyses of large families with many affected members are very useful for determining the inheritance pattern of single-gene diseases.