This document discusses human traits and genetics. It explains that traits are physical characteristics inherited from parents through alleles, which can be dominant or recessive. The genotype is an organism's genetic makeup represented by two alleles, one from each parent, determining the phenotype or outward physical appearance. It then lists over 20 common human traits and whether the dominant or recessive version is expressed.

1. I can…
 take an inventory of my observable traits and
compare them to the observable traits of family
members.
 differentiate between dominant and recessive
traits.

2.  There are over 200 traits that are transmitted from generation
to generation in humans. Traits are physical characteristics that
you inherit from your parents.
 An alternate form of a gene for a trait is called an allele.
 Blue, brown and green are alleles for eye color
 Alleles may be dominant (B) or recessive (b)

3.  Genotype
 The genetic make-up of an organism.
 Represented by two alleles (one from mom, one from dad)
 Homozygous (BB, bb) OR Heterozygous (Bb)
 Phenotype
 The outward, physical appearance of an organism as a
result of its genotype. (brown hair, left handed, freckles)
 If the dominant allele is present we will see the dominant
trait (BB, Bb). We only see the recessive trait expressed in
the absence of a dominant allele (bb).

5.  Look at each trait and determine your
phenotype (outward appearance)
 Identify if you exhibit the dominant or
recessive version of the trait

6. Male (XY) Female (XX)
Your sex is determined by whether you get an X or Y chromosome
from your father. Everyone receives an X from their mother.

7. Right handedness (HH, Hh) is dominant over left-handedness (hh).

8. Earlobes may be free (EE, Ee) or attached (ee).

9. Tongue-rolling (RR, Rr) is dominant to non-rolling (rr).

10. The inability to fold the tongue (FF, Ff) is dominant to tongue folding (ff).

11. Dimples may be present (DD, Dd) or absent (dd).

12. Hair on the middle finger bone, called mid-digit hair (MM, Mm) is dominant
to no hair (mm). You have the trait even if there is only one hair present!

13. Clasp your hands without thinking about it!
Left thumb on top (LL, Ll) is dominant to right thumb on top (ll).

14. Chins may have a cleft (CC, Cc) or no cleft (cc).
Some have called this a “butt chin”!

15. Hairlines may have a widow’s peak (WW, Ww) or be straight (ww).

16. Freckles (KK, Kk) are dominant to no freckles (kk).

17. Vulcan hand (VV, Vv) is dominant over earthling hand (vv).

18. Straight thumb (SS, Ss) is dominant to hitchhiker’s thumb (ss).

19. Bent little finger (BB, Bb) is dominant to straight little finger (bb).

20. Morton’s Toe, also called “long toe” is the common term for the
second toe extending past the big toe.
Morton’s Toe (TT, Tt) is dominant over a longer big toe (tt).

21. If you cannot see the
number inside the
circles, you may be
colorblind.
Normal (NN, Nn) is
dominant over
colorblindness (nn).

22. Polydactyly, or six digits (PP, Pp) is dominant to five fingers (pp).