Rebops. Your Rebop Traits Alternative forms. Procedure (work in pairs):

Transcription

1 Rebops The power of sexual reproduction to create diversity can be demonstrated through the breeding of Rebops. You are going to explore genetics by creating Rebop babies. Rebops are creatures that have several easily distinguishable traits (phenotypes). Please take a few minutes to observe the Rebops and make note of the visible traits and their alternative forms. Record your observations in the table below. Trait (i.e. Legs) Your Rebop Traits Alternative forms (i.e. Blue or Red) Procedure (work in pairs): A. The gene pool contains sets of purple and yellow chromosomes. One team member will start with a set of purple chromosomes; the other team member will start with a set of yellow chromosomes. B. Take the chromosomes out of the envelope and place them all face down on the lab table. LEAVE THEM FACE DOWN UNTIL DIRECTED TO TURN THEM OVER! Describe the chromosome composition of the Rebob. How many chromosomes? How many types of chromosomes? How many of each type? What do you need to do to make Rebop offspring? C. MEIOSIS Arrange the chromosomes so that similar lengths are matched up. The purple colored chromosomes represent the diploid chromosome set of the female Rebop. The yellow colored chromosomes represent the chromosomes of the male Rebop. Each chromosome has one allele for one Rebop gene. In order to determine what your Rebop offspring will look like you need to do a genetic cross of the parent Rebops. D. Making Rebop germ cells (eggs and sperm): Flip the coin: Heads choose the dominant allele (Upper case letter). Tails - choose the recessive allele (Lower case letter) Repeat this process for each chromosome. After you have completed this process, you now have produced a haploid germ cell (egg or sperm). Rebops Page 1 of 5

2 E. FERTILIZATION: Combine your haploid germ cell with the other team member s haploid germ cell and arrange the chromosomes by length. Fertilization has just taken place and you now have a Rebop ZYGOTE. F. The combination of upper and lower case letters is the baby Rebop s GENOTYPE. Record your allele combinations in the chart below (Write both copies with the same letter in each box): (i.e bb or BB or Bb) Your Baby Rebop Allele Combinations Rebops Page 2 of 5

3 Using the Rebop Decoder Key below, determines the characteristics of your Rebop and fill in the Genotype/Phenotype Table with your data: AA = 2 Antenna Aa = 1 Antenna aa = No Antenna QQ = Yellow nose Qq = Orange nose qq = Red nose EE = 2 eyes Ee = 2 eyes ee = 3 eyes DD = 3 Body segments Dd = 3 Body segments dd = 2 Body segments Rebop Decoder Key MM = 1 Green hump Mm = 2 Green humps mm = 3 Green humps TT = Curly tail Tt = Curly tail tt = Straight tail LL = Blue legs Ll = Blue legs ll = Red legs Your Rebop Genotype/Phenotype Table Trait Genotype Phenotype Number of Antenna Nose color Number of Eyes Number of Body Segments Number of Green Humps Tail Shape Leg Color H. Repeat the process to produce a second Rebop offspring for your partner.. I. Re-sort your alleles by color. Place all the purple alleles back in their envelope and do the same with the yellow alleles. Return the envelopes to the gene pool. STOP DO NOT GO ANY FURTHER UNTIL INSTRUCTED TO SO! Rebops Page 3 of 5

4 Part II J. Based on the data you filled into your Genotype/Phenotype Table, gather the materials you need to build your Rebop. You will also need one extra Marshmallow ball for the head and a round toothpick for the neck. K. GESTATION & BIRTH: Carefully build your Rebop according to the characteristics that resulted from your cross. Make sure that your Rebop expresses the phenotypes in your Genotype/Phenotype Table. L. Compare your Rebop with the other Rebops in the class. M. Observation Observe the Rebops in the group. Remember all of the Rebops are siblings. Qualitative Observations Quantitative Rebops Page 4 of 5

5 Discussion Questions 1. How many Rebops in the nursery are exactly alike? 2. Why do the majority of Rebops look different from each other (have Phenotypic diversity)? 3. If two of the Rebops look the same, does that mean their genotype is the same? a. Explain b. Under what circumstances could you be confident that the phenotype does express the genotype? c. What makes identical twins identical? 4. If the dominant trait is expressed in the phenotype, what can you say about the genotype of the individual Rebop expressing the dominant trait? 5. Looking at all the Rebops, are dominant or recessive traits more common? 6. Explain two things that helped you learn about genetics in this lab. Rebops Page 5 of 5