Laboratory: Exploring Hereditary Traits
Purpose: In this lab, you will be determining the presence of certain traits and determining your genotype based on the presence or absence of those traits.
Materials: PTC taste paperControl paper
Procedure:
1. For each trait listed below, read the description of the trait. Determine if you have that trait. Under the "phenotype" column, write yes or no for that trait.
2. Based on the presence or absence of the trait, determine your genotype(s) for each trait. Record the genotype under the appropriate column.
3. Pair up with another individual in your class. On a separate sheet of paper, make 22 punnett squares, one for each trait in this lab. Cross your genotypes with your partner's genotypes and determine the possible outcomes for your kids. Write out genotype and phenotype ratios for each.
4. If you have more than one possible genotype, either or both should select one of them to use. Mix and match - sometimes use BB, other times use Bb.
5. Now, determine what traits your kid would most likely have. If it is a 50/50 chance of either, flip a coin to decide. That's similar to the odds of having one trait or the other anyway.
6. Using the paper made available to you, draw a picture of your kid. Label all traits, and be sure to put your name on it.
Traits:
1. Tongue-rolling: Stick out your tongue and try to roll up the sides so that the tongue forms a U-shape.
2. Free-earlobe: The lobe of the ear hangs freely below the point of attachment to the
head.
3. Widow's peak: The midpoint of the hairline along the front of the forehead points downward.
4. Straight thumb: When extended from the palm of the hand, the top segment of the thumb forms a straight line with the bottom segment.
5. Straight little finger: The last segment of the little finger forms a straight line with the rest of the finger rather than bending toward the ring finger.
6. Left-over-right thumb crossing: When the hands are folded in a natural fashion, the left thumb crosses over the right.
7.Chin cleft: The center of the chin has an indentation resembling a deep dimple.
8.Mid-digital hair: Hair is present on the middle section of any of the ringers.
9.Six-fingers: Six ringers are present on either hand (or were present at birth).
10. PTC taster: Take a piece of control paper and place it on your tongue for 10 seconds. Throw that out. Then, take a piece of PTC paper and place it on your tongue for 10 seconds. Throw it out. If you taste a bitter taste, record yes on your data sheet. If it tastes like your control paper, record no on your data sheet.
11. Dimples: Smile. Have your partner observe whether dimples appear to either side of your mouth when your smile.
12. Freckles on cheeks: Have your partner observe your cheeks (on your face!) to see if any freckles appear.
13. Freckles on forehead: Have your partner observe your forehead for the presence of freckles.
14. Curly hair: Is your hair curly (not just wavy) or straight? If curly, record yes on
your data sheet.
15. Dark hair: Brown or black hair counts as dark. Red, or any shade of blonde does
not.
16. Non-red hair: If your hair is not red! Ignore any highlights in your hair. Just the color of most of it!
17. Brown, hazel, or green eves: If your eyes are any of these colors, this is dominant. If your eyes are blue or gray, record no on your data sheet.
18. Short big toe: Is your second toe bigger than your big toe?
19. Long eyelashes: Ladies, consider what they look like before applying mascara!
20. Almond-shaped eyes: If your eyes have more of an almond shape rather than round shape, record yes on your data sheet.
21. Right handedness: If you are right-handed, record yes on your data sheet. If you are left-handed, record no. If you can write equally well with both hands, record no.
22. Nearsightedness or farsightedness: If you require glasses or contacts to see distance
or nearby, record yes on your data sheet.
Data sheet
Trait / Phenotype (yes or no) / Genotype1. Tongue rolling
2. Free earlobe
3. Widow' speak
4. Straight thumb
5. Straight little finger
6. Left-over-right thumb crossing
7. Chin cleft
8. Mid-digital hair
9. Six fingers
10. PTC taster
11. Dimples
12. Freckles on cheeks
13. Freckles on forehead
14. Curly hair
15. Dark hair
16. Non-red hair
17. Brown, hazel, or green eyes
18. Short big toe
19. Long eyelashes
20. Almond-shaped eyes
21. Right handedness
22. Nearsightedness or farsightedness