DO NOW

1. OBJ: explain the principle of independent assortment. Explain how Mendel’s Principles apply to all organisms. KEY TERMS Independent assortment incomplete dominance codominance multiple alleles polygenic traits DO NOW Create a Punnett Square for a father who is homozygous recessive for tall gene and a mother who is heterozygous. What percent of their offspring will be tall?

2. Independent Assortment • Two factor cross F1 and F2 • Wanted to know if the recessive traits and dominant traits would group back together • The F2 generation of Mendel’s two factor cross produced seeds of both parents phenotypes as well as a large portion with mixed phenotypes • Alleles for the different traits segregated independently, known as independent assortment.

3. Independent Assortment (cont) • The principle of independent assortment states genes for different traits can segregate independently during the formation of gametes. • Helps account for the many genetic variations observed in plants, animals, and other organisms.

4. Mendel’s Principles • The inhertiance of biological characteristics is determined by individual units known as genes. Genes are passed from parent to offspring. • In cases in which two or more forms (alleles) of the gene for a single trait exist, some forms of the gene may be dominant and others may be recessive.

5. Mendel’s Principles • In most sexually reproducing organisms, each adult has two copies for each gene- one from each parent. These genes are segregated from each other when gametes are formed. • The alleles for different genes usually segregate independently from one another.

6. Not Dominant or Recessive • Incomplete dominance • Neither trait is dominant over the other • Heterozygous phenotype is a combination of the two homozygous

7. Codominance • Both alleles contribute to the phenotype • Both traits appear separately on the organism

8. Multiple alleles

9. Polygenic Traits