Predicting Heredity

1
Predicting Heredity
2
Symbols are used to represent the traits passed
on from parent to offspring.
3
Capital letters are used to represent a dominant
trait.
4
Lowercase letters are used to represent a
recessive trait.
5
Predicting Heredity

• One way to predict heredity is to use a chart
  called a Punnett square.

6
How to Punnett Square

• Draw a box with four squares.
• Write the genes for the mother down on the left
  side of the square.
• Write the genes from the father on the top of the
  square.
• Fill in each of the four boxes by giving one gene
  from each parent to each box.

7
Win, Lose, or Tie???

• Usually with genes, one gene will be a dominant
  gene and show itself while recessive genes are
  hidden unless they are homozygous recessive. But
  what happens if the traits are equally as strong?

8
INCOMPLETE DOMINANCE

• In these traits, both traits show up in some
  form or another in the offspring. This gene
  combination is called blending.

9
Incomplete Dominance Punnett Square
10

• Incomplete dominance produces offspring with
  hybrid genes for the given trait (neither one is
  dominant over the other).

11
Genotype

• The genetic makeup of an organism

12
Phenotype

• The physical trait that shows as a result of the
  genotype

13

• Red Heterozygous Flower
• Genotype
• Rr
• Phenotype
• Red

14

• Homozygous for Brown Eyes
• Genotype
• BB
• Phenotype
• Brown Eyes