Genetics: An Introductory Genetics: An Introductory to Inheritance and to Inheritance and

Physical TraitsPhysical TraitsBiologyBiology

Ms. KraftMs. Kraft

Ms. Sanford Ms. Sanford

How are the following How are the following parents and their babies parents and their babies

similar and different?similar and different?

Record your answers in the chart that Record your answers in the chart that your teacher has handed out for you.your teacher has handed out for you.

Note similarities and differences on your worksheet.

Note similarities and differences on your worksheet.

Note similarities and differences on your worksheet.

Note similarities and differences on your worksheet.

Note similarities and differences on your worksheet.

Traits of Simple Traits of Simple Inheritance in HumansInheritance in Humans

Now we are going to take a look at Now we are going to take a look at some of the simple traits that are some of the simple traits that are

easy to identify in humans.easy to identify in humans.

1. Do you have dark 1. Do you have dark eyes?eyes?

2. Can you roll your 2. Can you roll your tongue?tongue?

Tongue-Rolling: Rolling up edges (dominant trait) vs not rolling (recessive)

3. Are your earlobes 3. Are your earlobes detached?detached?

Earlobes: Free ear lobes (dominant trait) vs. Attached ear lobes (recessive trait)

Free earlobes are those that hang below the point of attachment to the head.  Attached ear lobes are attached directly to the side of the

head.

4. Do you clasp your right 4. Do you clasp your right thumb on top?thumb on top?

5. Do you have a widow’s 5. Do you have a widow’s peak?peak?

Widow's Peak (below) is dominant over no widow's peak hairline.

6. Do you have a cleft 6. Do you have a cleft chin?chin?

Dimples: Dimples (dominant trait) vs. No dimples (recessive trait) Dimples are natural dents in the face to the right or left of the mouth.  If a person

has only one dimple, they should be counted as having dimples. Cleft chin is dominant over no cleft.

7. Do you have a Hitch 7. Do you have a Hitch Hiker’s Thumb?Hiker’s Thumb?

Thumbs: Straight thumb (dominant trait) vs. Curved thumb (recessive trait) When viewed from the side as in the illustration below, curved thumbs can be seen as part

of a circle.

8. Do you have cheek 8. Do you have cheek dimples?dimples?

9. Do you have hair on 9. Do you have hair on your middle digit?your middle digit?

Mid-digit hair: Mid-digit hair (dominant trait) vs. No mid-digit hair (recessive trait)

10. Are you 10. Are you nearsighted?nearsighted?

If you are nearsighted, objects in the distance are blurry.