Week 4 Reflection: Pedigrees and Family Tree

This week in science we learned about pedigrees and family trees. A pedigree is a family tree that shows the genotypes of family members. By looking at a pedigree, you can determine the genotype of all family members by knowing only one or two genotypes. In a pedigree there are different symbols that represent gender, whether the person has or does not have the trait, and in x-linked cases if the female is a carrier. Typically on a pedigree, females are represented by circles and males are represented by squares. If the figure representing a person is shaded in they have the trait and if it is not they do not have the trait. In the case that the pedigree shows a x-linked trait a female's figure could be half shaded in meaning that the female is a carrier of the trait or disease. Each pedigree shows one trait, whether it is autosomal recessive, autosomal dominant, x-linked recessive, or x-linked dominant. Autosomal dominant is shown as two dominant alleles or one dominant and one recessive allele (AA or Aa), autosomal recessive is shown as two recessive alleles (aa), and x-linked is shown by the two alleles connected to the x chromosomes. Not only can you determine genotypes with a pedigree, but you can also determine whether a pedigree is showing an autosomal recessive, autosomal dominant, or x-linked trait by just using the figures and what they represent.

https://migrc.org/Library/AutosomalRecessive.gif