Mendel’s Experiments • Each gamete carries only one allele for seed shape, because the alleles have segregated during meiosis. Predicting Outcomes of Genetic Crosses • Mendel realized the principles of probability could be used to explain the results of genetic crosses. • Probability: the likelihood a particular event will occur. • The Basics of Probability: – What is the probability of flipping a coin to heads. – The more trials, the closer to expected ratio. – Past outcomes do not affect future outcomes. Predicting Outcomes of Genetic Crosses • Organisms can only pass on 1 of their 2 alleles for each trait (like flipping a coin) • Homozygous: – Have 2 identical alleles for a specific trait. – AA or aa • Heterozygous – Having 2 different alleles for a specific trait. – Can pass on either a dominant or a recessive trait – Aa