Happy Friday Take out a sheet of paper

Happy Friday! Take out a ½ sheet of paper and get ready for a quiz!

Name, 1 -15 -2010, Period n 1. Give the genotype for the following individual: QQ n 2. Identify the genotype for the following individual: Nn n 3. Identify the phenotype for the following individual: tt n 4. Give the genotypic ratio for a cross of two heterozygous individuals! Use a punnett square and label the parts of the ratio!

Human genetics n There are many human characteristics that you might have overlooked that exhibit the principle of dominance. n Lets look at a few within this class.

Ear Lobes n unattached or attached

Widow’s peak

Hitchhiker’s Thumb

Longer second toe

Dimples

Tongue Rollers

Which is dominant? Dominant Trait Recessive Trait Free Ear Lobes Attached Ear Lobes Widow’s Peak Straight Hair Line Hitchhiker’s Thumb Straight Thumb Longer Second Toe Longer Big Toe Dimples No Dimples Roll Tongue Not a Tongue Roller

What about us? n Many traits do not use this idea of simple dominance n Other ideas of how genetics are passed were also created to explain other phenomenon.

Incomplete Dominance n When using incomplete dominance one allele is not completely dominant over the other. n In incomplete dominance the heterozygous individual is somewhere between the two homozygous phenotypes

Tall vs. Short n I’m heterozygous for the Tall gene and my wife is homozygous short. What should the height of our children be if we have 4 kids?

Codominance n Sometimes both alleles are expressed in the phenotype and create mixtures. n This process is called codominance.

Blood types!

Another great example