Biology 10 Lab 9 Inheritance Simulation

Name______

Complete Dominance Incomplete Dominance Monohybrid Cross: Ww x Ww Sickle Cell Anemia Trait Cross: Ss x Ss (Ww=widows peak; ww=no peak) (SS = no sickle cell; Ss = sickle trait; ss = sickle cell disease)

Genotypic Ratio: Genotypic Ratio:

Phenotypic Ratio: Phenotypic Ratio: 2

Complete Dominance Incomplete Dominance PTC Taster Cross: TT x tt Familial Hypercholesterolemia (TT or Tt = taster; tt = nontaster Cross: Ff x ff (ff = normal cholesterol; Ff = high chol.; FF = very high chol.)

Genotypic Ratio: Genotypic Ratio:

Phenotypic Ratio: Phenotypic Ratio:

Physiology 31 - 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.) 3

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. 4

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 5

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