Presentation on theme: "Human Genetics Punnett Squares, Incomplete Dominance, Co-Dominance and Dominant/Recessive Traits."— Presentation transcript:
1 Human GeneticsPunnett Squares, Incomplete Dominance, Co-Dominance and Dominant/Recessive Traits
2 Punnett Squares Named after Reginald Punnett Gregor Mendel-pea plants Gene combinations/predictions
3 What to Know Capital letter – dominant trait Lowercase letter – recessive traitHomozygous – 2 identical allelesHeterozygous – 2 different allelesGenotype – genetic makeupPhenotype – physical characteristics
4 Examples T – dominant trait t – recessive trait TT- one example of genotypeIf T is for tall plants, then Tall is the phenotype for TTTT and tt are homozygousTt and tT are heterozygous
5 Incomplete Dominance BB is a dominant flower color of blue YY is a dominant flower color of yellowThe cross results in 100% green flowers
6 Codominance Both alleles contribute to the phenotype You will see each trait exhibited separatelyMany human genes show codominanceExample: chickens with both black and white feathers.
7 More ExamplesPolygenic traits – skin color, allergies, schizophrenia, cleft lip, and hypertensionMultiple alleles – human blood, coat color in rabbits