Sesame Street Genetics

Name: ______Period: ______Date: ______

Sesame Street Genetics

Background

Much is known about the genetics of the organism Sesamus muppetis. Karyotyping reveals that Sesame Street characters have six chromosomes: two homologous pairs and one pair of sex chromosomes. Chromosome pair #1 is the largest and has a centrally placed centromere. Chromosome pair #2 is shorter with the centromere at one end. Sex is determined by X and Y chromosomes just as in the related species, Homo sapiens. Through the process of gene mapping, geneticists have found the specific locations of the genes for eye shape, nose color, lip color, body color and hair type. By observing the offspring of many different crosses, geneticists have also determined the types of inheritance that several of these genes exhibit.

Gene Map

Chromosome # 1 Chromosome #2 X Chromosome Y Chromosome

Eye

shape Body

color Lip

color

Nose Hair

Color Type

Genetics of Sesame Street Characters

Your Task

In this activity, you will first determine the genotypes of six Sesame Street characters: Elmo, Telly, Grover, Zoe, Rosita, and Abby. Next, pick your favorite character from the list above! For that character, you will then be able to complete the following tasks:

·  Map the genes for this individual to the appropriate chromosomes, recording their genotype.

·  Simulate meiosis and the production of gametes.

Finally, you and another character of the opposite sex will get married and predict the characteristics of your future offspring.

Procedure

_____ 1. Create and complete a Phenotypes and Genotypes chart for all characters. Use the Genetics of Sesame Street Characters table to determine the genotype, or possible genotypes, of the traits for each character based on their phenotypes.

_____ 2. Choose one Sesame Street character. Next use the gene map in the background information to record their specific alleles on the karyotype shown on the Mapping the Genes sheet.

_____ 3. Copy the alleles from your gene map onto the two additional karyotypes provided on the Meiosis and Sex Cells sheet. Cut out these two sets of chromosomes and move them through the steps of meiosis in your imagination. Demonstrate this to your lab partner and pay attention as your lab partner demonstrates the process to you. Discuss the changes that occur in the chromosomes at each stage. Refer to your diagram of meiosis for help.

_____ 4. Tape the appropriate chromosomes onto the four sex cells worksheet to show the products of meiosis for your adult Sesamus muppetis.

_____ 5. Identify the traits that you find most desirable for a baby Sesamus muppetis. After all, you want your kids to be cute! Pick at least two.
_____ 6. On a separate piece of paper, calculate the chances of your character being able to have an offspring with these characteristics from each of the three members of the opposite sex using Punnett squares. Be sure to add this paper to your packet.

_____ 7. Choose a spouse. Once you are wed, offspring will be produced by combining the alleles from both parents during fertilization. Label the gametes one through 4 for each person. Flip a coin. If you flip a coin and see heads, eliminate the even numbered gametes (2,4). If you flip tails eliminate the odd numbered gametes. Flip the coin again. If you flip heads eliminate the higher number left. If you flip tails eliminate the lower number remaining. This is the gamete that will be fertilized. Have your spouse do the following process as well. of the four sex cells from your character and one of the sex cells from your spouse. Combine the alleles to produce one offspring. Repeat the “fertilization process” to create another child.

_____ 8. Create and complete a chart identifying the genotype and phenotype for the two offspring. Include information on eye color, nose color, hair, body color, lip color, and gender.

_____ 9. Your final task will be to draw a family portrait. The portrait must accurately show eye shape, nose color, lip color, body color, and hair type for each member of the family based on their alleles.

_____ 10. Reflection:

·  Would it be possible for a Sesamus muppetis with Magenta lips to produce an offspring with red lips? Why or why not?

·  What are the chances that a Sesames muppetis with red body color and a Sesamus muppetis with green body color will produce an orange offspring? Explain your prediction in words and with a Punnett square.

·  Predict what would happen to the Sesamus muppetis population in our classroom over a long period of time if a mutation occurred in one of the chromosomes resulting in a recessive allele for body color and the offspring were successful.