What is Heredity?
      What is Heredity?
  •Heredity = the passing on of 
   Heredity
   traits from one generation to the 
   next.
          What is a Trait?
          What is a Trait?
   A trait is a specific characteristic 
      trait
     that is unique.
     Traits affect the way we look
     Traits
     Traits affect how our bodies function
     Traits
     Traits are inherited
     Traits
       •Examples are hair color, eye color, 
        handedness, etc.
    How Do We Keep Track of 
    How Do We Keep Track of 
          Traits?
          Traits?
  •We use a pedigree chart to 
   keep track of how traits are 
   passed on from generation to 
   generation.
         What is a Pedigree?
         What is a Pedigree?
    A pedigree is a diagram that shows the 
      pedigree
      history of a trait as it is passed from one 
      generation to the next.
      Pedigrees indicate patterns
       Pedigrees
      Pedigrees identify carriers of genetic disorders
       Pedigrees
      Pedigrees are useful for genetic counseling
       Pedigrees
         • Example: a pedigree is like a family tree for one 
          trait.
     Rules For Making A Pedigree
     Rules For Making A Pedigree
  • Females are represented by circles
  • Males are represented by squares
  • Mother/Father couples are connected by a line
  • Offspring are shown oldest on the left to youngest 
   on the right
  • Half-shaded circle represents a female carrier for 
   the trait
  • Half-shaded square represents a male carrier for 
   the trait
  • Full-shaded circle represents a female with the trait
  • Full-shaded square represents a male with the trait