1. Single gene traits

2. Tongue rolling
The ability to roll your tongue is dominant, while non-rolling is recessive.

3. Free Ear Lobe Having a detached/free ear lobe is a dominant trait.
Having an attached earlobe is recessive.

4. Hand Clasping
Clasp your hands together. Notice whether your left or right thumb is on top. If your left thumb is on top, you have the dominant trait. If the right the thumb is on top, you have the recessive trait.

5. Hitchhikers thumb Straight thumb: Dominant
Hitchhikers thumb: Recessive

6. Bent little finger
Place the palms of your hands together gently, side by side with your palms facing towards you.
Dominant: Last two joints of finger bend away from each other
Recessive: Little fingers are straigaht

7. Widow’s peak
Dominant: Widow’s Peak
Recessive: Straight Hairline

8. Dimpled chin
Dominant: Chin Cleft
Recessive: Absence of Cleft

9. Mid-digital hair Hair on the middle segment of finger: Dominant
No hair: recessive

10. Pigmented Irises
When a person is recessive for this gene, they have no pigment in the front part of the eyes and a blue layer at the back of the iris shows through, resulting in blue eyes.
A dominant gene causes pigment to be deposited in front of the iris, masking the blue to various degrees.
Dark pigment (green/brown/black): Dominant
No pigment (grey/blue): recessive

11. Dimples
Dimples: Dominant
No Dimples: Recessive