Let’s Make BabiesNo sex involved!

A seatwork activity for Genetics class

Trait Dominant Recessive

Brown eyes Brown (BB or Bb) Non brown (bb)

Freckles Freckles (FF or Ff) No freckles (ff)

Tongue rolling Can roll (RR or Rr) Can’t roll (rr)

Dimples Dimples (DD or Dd) No dimples (dd)

Earlobe attachment

Unattached (EE or Ee) Attached (ee)

Widow’s peak Widow’s peak (WW or Ww)

Straight hairline (ww)

Cleft chin Cleft chin (CC or Cc) Smooth chin (cc)

Hair color Dark (HH or Hh) Light (hh)

Trait Dominant Recessive Phenotype Genotype

Brown eyes Brown (BB or Bb) Non brown (bb)

Freckles Freckles (FF or Ff) No freckles (ff)

Tongue rolling Can roll (RR or Rr) Can’t roll (rr)

Dimples Dimples (DD or Dd)

No dimples (dd)

Earlobes Unattached (EE or Ee)

Attached (ee)

Widow’s peak Widow’s peak (WW or Ww)

Straight hairline (ww)

Cleft chin Cleft chin (CC or Cc)

Smooth chin (cc)

Hair color Dark (HH or Hh) Light (hh)

Hair texture Curly (TT) Wavy (Tt)

Straight (tt)

Write your phenotype and the corresponding genotype. If you have non-brown eyes, for example, then write under phenotype “Non-brown” and under the genotype “bb”. If you can roll your tongue, write “Can Roll” under phenotype and either RR (homologous) or Rr (heterozygous). Choose RR if you are confident that everyone in your family/clan can roll their tongue. If you are unsure, write Rr. Same principle applies to the rest of the traits.

TABLE No. 1

Choose a Partner

Decide who will be the “sperm donor” and the “egg donor”.

Once you have decided who will be the sperm or egg donor, start “making” your sperm or egg.

Trait Allele Trait Allele

Brown eyes Brown eyes

Freckles Freckles

Tongue rolling Tongue rolling

Dimples Dimples

Earlobe attachment

Earlobe attachment

Widow’s peak Widow’s peak

Cleft chin Cleft chin

Hair color Hair color

Hair texture Hair texture

EGG No. 1 EGG No. 2

From your list of genotypes (Table 1), decide which allele will go to which Egg or Sperm. You can do this by tossing a coin. If Heads, the first allele will go to Egg/Sperm No. 1; if tails, the first allele will go to Egg/Sperm No. 2. For Example, if your genotype for Brown eyes is “Bb”, the toss a coin to check which egg or sperm will get the first allele (which is “B”). The remaining allele (“b”) will obviously go to the remaining egg or sperm.

Trait Allele Trait Allele

Brown eyes Brown eyes

Freckles Freckles

Tongue rolling Tongue rolling

Dimples Dimples

Earlobe attachment

Earlobe attachment

Widow’s peak Widow’s peak

Cleft chin Cleft chin

Hair color Hair color

Hair texture Hair texture

Gender Gender

SPERM No. 1 SPERM No. 2

If you are the sperm donor, add the Gender trait in your column. Toss a coin to randomly assign a gender to your sperm. If heads, assign the Male gender to the sperm. If tails, assign the Female gender to the sperm.

Baby No. 1: NameTrait Genotype Phenotype

Brown eyes

Freckles

Tongue rolling

Dimples

Earlobe attachment

Widow’s peak

Cleft chin

Hair color

Hair texture

Gender

With your chosen partner, combine your Gamete No. 1 with his/her Gamete No. 1. Or you can toss a coin. If Heads, combine your first gamete to his/her first gamete. If tails, combine your first gamete to his/her second gamete. Combine the alleles to form the genotype and identify the appropriate phenotype. For example, if Sperm No. 1 contains “B”, and Egg No. 1 contains also “B”, then the genotype of Baby No. 1 is “BB” and the phenotype therefore is “Brown eyes”.