Introduction to Genetics

1
Introduction to Genetics

• Chapter 11

2
Are Traits Inherited?
3
Gregor Mendel

• Used garden peas in his experiments
• Peas reproduce sexually in a process known as
  fertilization
• Pea plants were true breeders they produced
  identical offspring if they were allowed to self
  polinate

4
Gregor Mendel

• Studied 7 different pea plant traits
• He crossed plants and studied their offspring
• Original pea plant is the P generation
• Offspring are the F1 generation
• Offspring of crosses between parents with
  different traits are called hybrids

5
Principle of dominance

• Some alleles are dominant and others are recessive

6
Segregation

• Do recessive alleles disappear?
• F1 Cross
• P. 266

7
Probability Punnett squares
8
Genetics Probability

• Likelihood that a particular even will occur
  probability
• Flipping a coin. What are the chances it will
  land on heads? On tails?
• Alleles segregate completely random just like
  flipping a coin

9
Punnett Squares

• Can be used to predict and compare the genetic
  variations that will result from a cross

10
Punnett Squares

• Identical alleles for a particular trait
  homozygous
• Different alleles for a particular trait
  heterozygous
• Physical characteristics are called phenotypes
• The actual alleles present for a trait or the
  genetic make up is known as genotype