Themes > Science > Life Sciences > Physical Anthropology > Heredity and Genetics


Determining Your Genes:

Did you know that your genes determine whether or not you possess certain physical traits? Well, they do. It's your genes that make you blue eyed or brown eyed, or have brown or blond hair. These traits are highly complex, and involve the interaction of many genes. However, several traits are determined by only one gene, and if you have the gene then you have the trait.

You have two genes for every trait. You get one from your mother and one from your father. Certain genes are dominant, and you only need one of the pair to give you its trait. If you don't have a dominant gene, then you are recessive for that trait. Dominant genes are represented as capital letters and recessive genes as lower-case letters. Circle which genes you possess for each of the following traits.

 
Tongue Rolling: Can you roll your tongue into a U-shape? Try it. If you can, then you possess the dominant gene and should circle "T-". If you can't roll your tongue, you have two recessive genes, and should circle "tt".


Tongue Rolling

                   
T-              tt 
(circle one)

Attached Earlobes: Have a partner examine your earlobes. If they hang free at the bottom, you are dominant (E-). If they are attached, you are recessive (ee).


Attached Earlobes

     
E-           ee

Interlocking Fingers:
Fold your hands together by interlocking your fingers. Which thumb is on top? If the left thumb is on top, you are dominant (I-). If the right thumb is on top, you are recessive (ii).


Interlocking Fingers

     
I-             ii

Dimples:
Dimples are a dominant trait (D-). If you don't have dimples, you are recessive (dd).


Dimples

     
D-            dd

Sex:
Males possess a "Y" chromosome and should circle XY. Females possess two "X" chromosomes and should circle XX.


Sex

     
XY            XX

Bent Little Finger:
Look at the little finger on each hand. If they bend in toward your ring finger, you have the dominant gene.


Bent Little Finger

     
L-                ll

Double Jointed Thumb:
If you have double jointed thumbs, you have the dominant gene.


Double Jointed Thumb

     
J-                 jj

Freckles:
If you have freckles then you have a dominant gene (F- ). If you don't have freckles then you are recessive (ff).

Freckles

     
F-                ff

PTC Taste:
Chew a taste strip. Some people can taste PTC, and others cannot. If the strip tastes bitter to you, you are a "taster" and have the dominant gene for this trait (P-). If the strip doesn't taste like anything, you are recessive (pp). 70% of the people in the United States are "tasters". Is anyone in the room a "non-taster"??


PTC Taste

     
P-              pp

Sodium Benzoate Taste:
Different genes determine if you can taste sodium benzoate. If it tastes salty, bitter, or sweet to you, then you have the dominant gene (S-). If you don't taste anything, you are recessive (ss).


Sodium Benzoate Taste

     
S-                ss

Widow's Peak:
If your hairline is shaped in a downward "V", then you are dominant for that gene (W-).


Widow's Peak

     
W-                 ww


Information provided by: http://student.biology.arizona.edu