genetics

• Pedigree


  A way of analyzing the inheritance patterns of a trait within a family
• Pedigree


  • Can be useful to understand more about a trait, make insights about the genetics of the trait, and think about what has happened in the past in a family to help get probabilities or understanding of what might happen in the future
• Circle


  Represents a female in the family
• Square


  Represents a male in the family
• Colored in circle/square


  Indicates the person exhibits the trait
• Phenotype


  The observed trait
• Genotype


  The genetic makeup of an individual
• Marriage line


  Horizontal line connecting a male and female, indicating they are coupling up and reproducing
• Line of descent


  Vertical line going from the marriage line to the next generation
• Sibling line


  People directly connected to the line of descent, indicating they are brothers and sisters
• Autosomal dominant trait


  A trait associated with one of the non-sex chromosomes, where having even just one allele for the trait will result in the trait being expressed
• Freckles is an autosomal dominant trait
• Determining genotype of individual I-2

  1. They exhibit the freckles phenotype

  2. They cannot be homozygous dominant (capital F, capital F) because then all their children would have freckles, but some do not

  3. Therefore, they must be heterozygous (capital F, lowercase F)
• The individual I-2 coupled with must be homozygous recessive (lowercase F, lowercase F) since they do not exhibit the freckles phenotype