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Biology 10 Lab 9 Inheritance Simulation by 7bO719VH

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									                  Anatomy & Physiology 34A - Inheritance Simulation Lab

Students form groups of two and follow the handout instructions to see how several monogenetic
traits are inherited via meiosis and the recombination of chromosomes during fertilization.

Materials (per groups of 2 students each)
- 18 blue popsickle sticks or wooden tongue depressors
- 18 pink popsickle sticks or wooden tongue depressors
- One inch wide masking tape
- Dark colored marking pen (such as a Sharpie)
- 2 Handouts on genotypes and phenotypes

Directions
1. Form groups of two.
2. One person will pick up 18 blue sticks and the other will pick up 18 pink sticks from the box.
3. Tape your same color sticks together in pairs, so that you each have 9 pairs of sticks
 (homologous chromosomes).
4. Determine whether you are homozygous recessive or heterozygous (if you have a dominant
   phenotype, we’re going to assume you’re heterozygous) for each of the nine traits on the
   genetic traits handout, and record your genotype and your partner’s on the handout.
5. If you are homozygous recessive for a trait, print one lower case letter that represents that
   allele on each side of the TAPE on one pair of sticks. (Please do NOT write directly on the
   sticks.)
6. If you are heterozygous for the trait, print one lower case letter on the tape on one side of the
 pair of sticks, and the corresponding capital letter on the other side of the sticks.
7. Do steps 4-6 for all 9 genetic traits, using one pair of sticks for each trait.
8. Once both you and your lab partner have completed labeling your “homologous
   chromosomes,” you will both toss your sticks onto the table top. This step represents the
   independent assortment of homologous chromosomes during meiosis.
9. After the “chromosomes” land, pair up the letters (alleles) on the blue and pink sticks. This
   step represents the recombination of homologous chromosomes during fertilization.
10. Record the genotypes and phenotypes of your first offspring on the handout.
11. Repeat steps 8-10 for a second offspring.
12. Compare the genotypes and phenotypes of your two “offspring.” Did they both have the
   same or different traits?
13. When you finish, remove the tape from the sticks and return them to the box.
                                                                                             2


Trait              Dominant          Genotype   Recessive        Genotype   Phenotypic
                   Phenotype                    Phenotype                   Ratio in Class
Earlobes           Free              EE or Ee   Attached         ee

Hairline           Widow’s peak      WW or Ww   No widow’s       ww
                                                peak
Tongue             Able to roll      RR or Rr   Unable to roll   rr

Hitchhiker’s       No 60° bend       HH or Hh   Bends 60°        hh
thumb
Little Finger      Bent              BB or Bb   Straight         bb

Hairy              Hairy             MM or Mm   Hairless         mm
Mid-digits
Interlaced         Left thumb over   CC or Cc   Right thumb      cc
fingers            right                        over left
PTC                Tastes bad        TT or Tt   Tasteless        tt
taster/nontaster
Gender             Female            XX         Male             XY
                                                                                                                 3


Genotypes and Phenotypes from inheritance simulation.

                                                    First Offspring               Second Offspring

Trait            Your Genotype    Your Partner’s    Genotype          Phenotype   Genotype           Phenotype
                                  Genotype
Earlobes

Hairline

Tongue

Hitchhiker’s
thumb
Little Finger

Hairy
Mid-digits
Interlaced
Fingers
PTC

Gender

								
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