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.
Individuals on a pedigree chart that have unshaded symbols have at least one dominant gene, and show the dominant trait. Rules one must follow to predict genotype: Any person on a pedigree chart that has a shaded symbol must be assigned two (2) recessive genes. Place lower case letters under the person's symbol. Any person on a pedigree chart that has an unshaded symbol must be assigned a dominant gene. Place a capital letter under the person's symbol. To determine the second gene for persons who show a dominant trait a Punnett square must be used.