MAKE A BABY LAB
In order to determine the hereditary traits of your child, you and your partner will flip two coins; first, to
determine the sex and then, to determine the facial traits that your child will receive.
Once the sex and facial traits of your child have been determined by the coin flips, you will draw a picture of your
child according to these traits.
The following concepts are explained and illustrated in this activity:
a)
b)
c)
d)
e)
Each parent contributes one-half of each child’s genetic makeup.
Genotype and phenotype characteristics
Incomplete dominance or co-dominance
Polygenetic inheritance
Sex-limited traits
When flipping the coins, heads stand for the dominant genes (capital letters) and tails stand for the recessive
genes (lower case letters). As the coins are flipped and the genes from the mother and father are determined for each
trait, fill in your data sheet.
First, you must determine the sex of your child. Why does only one parent need to flip for the sex of the child?
Which parents should flip a coin to determine the sex of the child? Heads will be a girl (X-chromosome sperm) and tails
will be a boy (Y-chromosome sperm). Give the child a name and record the name and sex on the data sheet.
Since each parent contributes one-half on the child’s genetic makeup, each parent must flip a coin for each of the
following facial traits. Carefully record on your data sheet the gene from both parents coin flips.
Flip your coins to first determine your child’s face shape.
1. Face Shape:
Round (RR or Rr)
Square (rr)
The next three flips determine chin shape.
2. Jaw Shape:
Very Prominent (V V or V v)
Less Prominent (v v)
Only flip coins for the next two traits if the chin shape genotype is VV or Vv. The genotype vv prevents the expression of
the next two pairs of genes.
3. Chin Shape:
Round (RR or Rr)
Square (rr)
4. Cleft Chin:
Present (AA or Aa)
Square (aa)
To determine the color of skin, assumer there are three gene pairs involved. Flip your coins first to determine the
genotype of the first pair of genes (AA, Aa, or aa). Circle the outcome of your coin flips. The flip your coins again to
determine the genotype of the second pair of genes (BB, Bb, or bb). Circle the outcome of that coin flip. Now flip for the
third pair of genes (CC, Cc, or cc). Circle the outcome of that coin flip. Each capital letter represents and active allele
(gene) for pigmentation. Examine the chart below in order to determine the skin color of your child.
5. Skin Color:
Genes
6 capitals
5 capitals
4 capitals
3 capitals
2 capitals
1 capital
6. Hair Type:
Curly (CC)
Skin Color
Very dark black
Very dark brown
Dark brown
Medium brown
Light brown
Light tan
Wavy (Cc)
Straight (cc)
7. Widow’s Peak: The hair line comes to a point in the center of the forehead.
Present (WW, Ww)
Absent (ww)
8. Color of Eyebrows: Consider all eyebrow traits (next three) before drawing.
Very dark(BB)
Medium dark (Bb)
Light (bb)
9. Eyebrow Thickness:
10. 10. Eyebrow Placement:
Bushy (BB, Bb)
Fine (bb)
Not connected (NN, Nn)
Connected (nn)
11. Eyebrow placement:
12. Eye Color: Darker eyes are produced in the presence of more active alleles. In this situation, the large letters (A
or B) represents alleles which are active in depositing dark pigment. Small letters (a and b) represents alleles
which deposit little pigment.
To determine the color of the eyes, assume there are two gene pairs involved, one which codes for depositing
pigment in the front of the iris, and one which codes for depositing pigment in the back of the iris. Determine the
genotype of the first pair (AA, Aa, or aa) and then the second pair (BB, Bb, or bb). Match the genotypes with the
color. In reality, the determination of eye color is much more complicated.
1
2
1
2
AABB
Dark Brown
AAbb
Dark Blue
AABb
Brown
aaBB
Dark Blue
AaBB
Brown
Aabb
Light Blue
AaBb
Brown
aabb
Pale Blue
aaBb
Blue
The next four flips determine the phenotype with respect to all four flips before drawing the eyes.
12. Eyes - distance apart:
Close together (EE)
Average distance (Ee)
Far apart (ee)
13. Eyes - size
Large (EE)
Medium (Ee)
15. Eyes - Slantedness
Horizontal (HH, Hh)
Small (ee)
14. Eyes - Shape:
Almond (AA, Aa)
Round (aa)
Upward Slant (hh)
16. Eye lashes
Long (LL, Ll)
Short (ll)
Mouth and lip traits will be determined in the next four flips
17. Mouth Size
Long (MM)
Average (Mm)
Short (mm)
18. Lips
Thick (LL, Ll)
Thin (ll)
19. Protruding Lip:
Very protruding (HH)
Slightly Protruding (Hh)
Absent (hh)
20. Dimples
Present (DD, Dd)
Absent (dd)
Nose and ear traits are determined in the next 7 flips. Record your genotypes on your data sheet but do not draw
these features until all the traits are established.
21. Nose Size:
22. Nose Shape:
Big (NN)
Medium (Nn)
Small (nn)
Rounded (RR, Rr)
Pointed (rr)
23. Nostril Shape:
Rounded (RR, Rr)
Pointed (rr)
The next four flips along with the proceeding flip controls ear traits.
24. Earlobe attachment:
25. Darwin's Earpoint
Free (FF, Ff)
Attached (ff)
Present (DD, Dd)
Absent (dd)
26. Ear Pits:
Present (PP, Pp)
Absent (pp)
27. Hairy Ears: (limited to males!)
Present (HH, Hh)
Absent (hh)
28. Freckles on cheeks
Present (FF, Ff)
Absent (ff)
29. Freckles on forehead:
Present (FF, Ff)
Absent (ff)
30. Hair Color: Hair color is a polygenic trait (several sets of genes are involved). To mimic this affect, flip your
coins three times. The following is a chart indicating the hair color depending on how many heads you get. Use A,
B, and C.
6 heads - black hair
4 heads - medium brown
2 Heads - dark brown 0 heads- pure blond
5 heads - dark brown
3 heads - light brown
1 head - light blond
(almost white)
Before