Name_______________________________________________________ Date_______________
We are going to take a closer look at ourselves, specifically, many different dominant / recessive traits of the human genome. We will be able to determine our phenotype for all the traits. We will try to figure out our genotype if possible as well.
1. Straighten your thumb. If your thumb bends back past straight, you have what is called "hitchhikers' thumb" and must have at least one dominant allele (H_). Straight thumbs are homozygous recessive (hh). Check your thumb and record your phenotype in a chart.
2. A dominant allele (D_) gives some people dimples. People homozygous recessive (dd) do not have dimples. Check in the mirror and record your phenotype.
3. A dominant allele (R_) gives some people the ability to roll their tongue into a tube. Homozygous recessives (rr) cannot form a tube out of their tongue. Can you? Record your phenotype.
4. Tongue folding is another dominant trait. People with a dominant (T_) can fold or flip their tongue upside down. Try to flip yours and look in the mirror. If you cannot, you must be homozygos recessive (tt). Record your phenotype.
5. A dominant allele (F_) gives some people freckles whereas not having it (ff) results in no freckles. Look in the mirror and record your phenotype.
6. Unattached earlobes (L_) are dominant over free earlobes (ll). Which are you? Record your phenotype.
7. Hair growth on the middle sections of one's fingers is dominant (M_). No hair would be homozygous recessive (mm). Examine your fingers and record your phenotype.
8. Curly hair is a dominant trait (C_) over straight hair (cc). Which are you? Record.
9. Having arched feet is dominant (A_) over flat feet (aa). Record your phenotype.
10. A hairline that grows to a point in the middle of the forehead is called widow's peak and is dominant (W_) over a straight hairline (ww).
11. Long eyelashes are dominant (E_) over short eyelashes (ee). Which do you have? Record.
12. Lay your hand flat on a table. Pinky fingers that bend sideways are dominant (P_) over the recessive (pp) straight pinky. Record your results.
13. Blue eyes are recessive (bb). Any dominant allele (B_) will result in non-blue eyes. Record your results.
14. Red hair is another recessive trait (nn). If your hair is non-red, you have a dominant allele (N_).
Make a table summarizing your phenotypes.
Why did I have a blank after each of the dominant alleles (i.e. C_)?
Which traits could you determine your full genotype for?
What information would you need in order to determine your genotype on those other traits?