1. Copyright © 2004 Stevens Institute of Technology, CIESE, All Rights Reserved. Human Genetics: Dominant & Recessive Traits Edited by D Wagner 10/20/08

2. Copyright © 2005 Stevens Institute of Technology, CIESE, All Rights Reserved. The physical characteristics below are common genetic traits inherited from one generation to the next:  Free vs. Attached Earlobes  Straight vs. Curved Thumbs  Bent vs. Straight Pinky  Can vs. can’t roll your tongue  With vs. Without Widow’s Peak Review the following slides that contain:  Definition and images of each genetic trait  Identification of the Dominant / Recessive trait Human Genetics: Dominant & Recessive Traits

3. Copyright © 2005 Stevens Institute of Technology, CIESE, All Rights Reserved. Free vs. Attached Earlobes Free earlobes (dominant trait) hang below the point of attachment to the head. Attached ear lobes (recessive trait) are attached directly to the side of the head.

4. Copyright © 2005 Stevens Institute of Technology, CIESE, All Rights Reserved. Straight vs. Curved Thumbs Straight thumbs (dominant trait) can be seen as nearly a straight line and may contain a slight arch when viewed from the side as in the illustrations. Curved thumbs (recessive trait) can be seen as part of a circle.

5. Copyright © 2005 Stevens Institute of Technology, CIESE, All Rights Reserved. Bent vs. Straight Pinky Bent pinky (dominant trait) vs. Straight pinky (recessive trait): 1.Hold your hands together as if you are covering your face. 2.If the tips of the pinkies (or baby fingers) point away from one another, the pinkies are bent (dominant trait).

6. Copyright © 2005 Stevens Institute of Technology, CIESE, All Rights Reserved. Ability to roll your tongue Roll your tongue(dominant trait) is the ability to roll your tongue Inability to roll your tongue is the recessive trait.

7. Copyright © 2005 Stevens Institute of Technology, CIESE, All Rights Reserved. With vs. Without Widow’s Peak Has a Widow’s Peak(dominant trait) is a pointed area of hair in the center of the forehead. The photos to the left clearly shows widow’s peak. No Widow’s Peak is the recessive trait.