Introduction to Genetics Chapter 11

Are Traits Inherited?

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

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

Principle of dominance Some alleles are dominant and others are recessive

Segregation Do recessive alleles disappear? F1 Cross P. 266

Probability & Punnett squares

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

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

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