Applying Mendel’s Principles

Probability and Punnett Squares Probability- is the likelihood or chance that a particular event will occur.  Example: Flipping a coin or making free throws.  What is the probability of a coin landing heads every time?  Probability= the number of times a particular event occurs THE NUMBER OF OPPORTUNITIES FOR THE EVENT TO OCCUR

The way in which alleles segregate during gamete formation is just as random as flipping a coin.

Homozygous vs. Heterozygous Homozygous- Having two identical alleles for a particular gene.  Examples: TT or tt Heterozygous- Having two different alleles for the same gene.  Example: Tt

Phenotype vs. Genotype Phenotype- Physical or observable traits.  Examples: Height, eye color, hair, etc. Genotype- Genetic make up which is inherited.  Examples: TT, Tt, tt

Using Punnett Squares Punnett squares use mathematical probability to help predict the genotype and phenotype combinations in genetic crosses.

Independent Assortment How do alleles segregate when more that one gene is involved?  Example: Does the shape of a seed affect the gene for seed color? RRYY and rryy To determine this Medel created and used a two- factor cross or dihybrid cross.

Independent assortment- States that genes for different traits can segregate independently during the formation of gametes.

Dihybrid Cross RRGG X rrgg