Genetic Game Gecko Master

“Gecko Breeding Challenge” A local zoo wants to hire someone to develop plans to breed rare animals. You will take on the role as a breeder and geneticist so you may win the Zoo’s business, and attract future clients in the exotic animal and pet industry. Worldwide, the exotic animal trade is a multibillion dollar industry, so you have a great opportunity to begin your career as a geneticist and breeder. While you are not an expert at breeding geckos, you are confident that you can develop a successful plan because you already have some ideas about how traits are passed on from parents to children and you believe you can learn what you don’t know. The geckos that you can breed are shown below. Type of Leopard Gecko Picture Gene Normal N/A Albino Albino Blizzard Blizzard Patternless Mack Snow ________________________ Patternless Mack Super Mack Snow Mack Enigma Enigma Giant Looks like Normal, but bigger. Giant Male: 90-109g in first year of life Female: 80-89g in first year of life Supergiant Looks like Normal, but bigger. Male: More than 110g at 1 year old Female: More than 90g at 1 year old Weights for all geckos other than Giant and Supergiant: Male: 70-90g (as adult) Female: 50-70g (as adult) Background Research After researching the principles of genetics, you have found the following information to assist with your breeding efforts. Genes are segments of DNA that determine an individual’s traits or phenotype. Each one of these genes has different version called an allele. For example, the trait of eye color comes in different varieties like brown, green, and blue because individuals have different allele, versions of the gene. Since meiosis splits up pairs (homologous) of chromosomes, each parent passes on one copy of each gene. Consequently an individual has two copies of every gene, one from mom (maternal) and one from dad (paternal). The genotype or combination of alleles for an individual determines their phenotype or traits. The two alleles for a trait can interact in different ways. If an allele covers up another version of the gene, its considered dominant and represented with a capital letter. So whenever an individual possesses a dominant allele, he or she will have the dominant phenotype trait . Recessive alleles are represented by lower case letters, and the recessive phenotype (trait) is hidden when an individual also has a dominant allele. For a given trait, if an individual has two different alleles the genotype is heterozygous (ex. Gg, Tt, Ee, Ff). If an individual has two of the same alleles the genotype is homozygous (ex. GG, gg, TT, tt, FF, ff). In a paragraph, describe which Geckos you plan to breed in order to produce a rare type of Gecko unlike any pictured above. Explain your reasoning. “Inheritance Rules” To begin you breed a blizzard male with a normal female and get the results below. Male Blizzard Parent Female Normal Parent Mated with… All Normal Offspring Produced… As with the cross above, you cannot always easily predict the outcome of a cross, just considering the phenotypes of the parents. Use pictures A and B below to help understand the process of inheritance. Describe how offspring are generated based on picture A. Picture A Describe how picture B illustrates each of the three inheritance rules. If you prefer, you can write or draw on the picture to show where you think each of the rules is depicted. a. Each organism has two copies (alleles) of each gene. b. Each organism gets one allele from the male parent and one allele from the female parent. c. Offspring can only inherit the alleles that are present in the parents. Picture B “Inheritance Simulation” Often, as scientists and engineers, it is helpful to test predictions in some way before time and money are invested in a full-blown solution or a major experiment. Sometimes, it is better to do those tests using a simulation that is based on scientific knowledge. As a class, you will design a simulation that can be used now to test your predictions about 1gene and later on to test your predictions as you work with more genes. You will work in pairs to do this activity. Designing the Simulation Activity: Remember to keep in mind the inheritance rules you wrote and the information in the fertilization pictures (A and B) to help you justify the steps in the simulation. Procedure for Simulation Activity: Inheritance through Generation of Offspring The procedure may be very simple, but in order to use this procedure again for more than one gene, you need to write down the steps precisely. Resources available to you: Pictures A and B Inheritance Rules The activity materials Two paper geckos (one male and one female) Two bags of shapes (one for each gecko) Two bags of gametes (A gamete is a generic term for egg and sperm: eggs for the female gecko and sperm for the male gecko) The activity designer has chosen to represent different types of genes with different shapes and to represent the different alleles for each gene with different colors. To figure out what you have been given: Each person should take one of the bags of shapes, and making sure to keep the contents of the bags separate, dump the contents on the desk and answer the questions below. a. How many different types of shapes do you have? Therefore how many different genes do you have? b. How many different colors do you have? Therefore how many different alleles do you have? c. What is the genotype of parent 1? What is the genotype of parent 2? d. Why do you think you have multiple squares of each color and multiple eggs or sperm? e. How does this relate to either Picture A or B about how offspring are formed? Making the Prediction Write down the cross that is being performed in this simulation activity: a. If these parents were to have 16 offspring, write down the different allele combinations you would expect to see and how many offspring will have each allele combination. Allele Combinations Number of Offspring with that Allele Combintion Name Understanding Inheritance Teacher Date Task D: Developing a Model of Inheritance for One Gene Task D3: Worksheet 4b: Connecting the process of inheritance with the outcomes Part I: Procedure for Putting Alleles in Eggs and Sperm 4) Write down the step(s) you will take to put alleles in eggs and sperm. STEP JUSTIFICATION (Inheritance Rule or Information from Picture A or B) 5) Follow that step for all the gametes (eggs or sperm) you have. a. Fill out the Eggs and Sperm Table to show what types of eggs and what types of sperm your geckos will produce: EGGS SPERM Name Understanding Inheritance Teacher Date Task D: Developing a Model of Inheritance for One Gene Task D3: Worksheet 4b: Connecting the process of inheritance with the outcomes Part II: Procedure for Making Offspring Now that you have instructions for generating eggs and sperm. 6) Write down the step(s) you will take to make offspring from the eggs and sperm. STEP JUSTIFICATION (Inheritance Rule or Information from Picture A or B) 7) Follow that step for all the eggs and sperm you have. a. Write down the allele combinations you saw in the offspring. Evaluating Your Predictions b. Were your predictions about the types of allele combinations expected in the offspring supported by the simulation or not? How do you know? c. Were your predictions about the number of offspring with each allele combination supported by the simulation? Why or why not? 1. What difficulty with your thinking caused your predictions to be inaccurate when you made them? 2. What have you learned that will help you make better predictions in the future? (Aren’t you glad you didn’t have to wait for the geckos to breed and hatch and invest in PCR before you found out whether your predictions were accurate?!) Name Understanding Inheritance Teacher Date Task D: Developing a Model of Inheritance for One Gene Task D3: Worksheet 4b: Connecting the process of inheritance with the outcomes 8) Now, predict the results of this cross:  X  Egg and Sperm Table: EGGS Predictions Pedigree: SPERM   Name_______________________________Teacher______________________Date_________ Understanding Inheritance Task D: Developing a Model of Inheritance for One Gene Task D5: Worksheet 4e : Application of One Gene Model 1) Suppose you are a genetic counselor (a professional who helps couples identify and discuss the probability of having children with inherited disorders). The couple shown below has come to see you: They are interested in having children, but are concerned about the possibility of one being born with cystic fibrosis. Cystic fibrosis is a disease that causes mucus to build up in the lungs and other areas of the body, and results in a shortened life span. The genotype for a person with cystic fibrosis is while healthy children are either  or . a. In the space above, complete the prediction pedigree to show possible offspring genotypes as well as the proportions of offspring genotypes. Support your answer with an egg & sperm table (below) and your math equation. EGGS SPERM Name_______________________________Teacher______________________Date_________ Understanding Inheritance Task D: Developing a Model of Inheritance for One Gene Task D5: Worksheet 4e : Application of One Gene Model b. The couple tells you they are expecting their first child. What is the chance/probability that this child will be a healthy heterozygote? Explain how you know. c. What is the chance/probability this child will have cystic fibrosis? Explain how you know. d. The couple returns to your office a few years later along with their healthy first child, and tell you they are expecting their second child. Does the chance/probability of having cystic fibrosis change for this second child? Explain to the couple why or why not. Name_______________________________Teacher______________________Date_________ Understanding Inheritance Task D: Developing a Model of Inheritance for One Gene Task D5: Worksheet 4e : Application of One Gene Model 2) Humans have three possible alleles for the gene that determines blood type, shown below: Using this information and the outcomes pedigree below, answer the questions below. a. What is the genotype of person 2c? Explain how you know using the inheritance rules. b. What are the possible genotypes for 1c? Explain your answer using inheritance rules. Connecting Pedigrees to the Gecko Design Challenge Apply your knowledge of pedigrees to the breeding of Geckos by predicting the outcome of the crosses below. A blizzard genotype is , and normal genotypes are either or . Suppose you now perform the following crosses: 1) X  2) X  a. Which cross is more likely to give you a blizzard gecko? Show your reasoning using a math equation and/or pedigree. b. Is getting a blizzard a rare event from either mating? Explain why or why not. c. Revisit your original design plan, on the first page of the Gecko challenge. -What knowledge do you have now, that will help you design a rare Gecko? -Modify your plan if needed to produce a rare Gecko. -What information or resources do you still need to breed a rare Gecko for the zoo? Name Understanding Inheritance Teacher Date Task E: Extending the Model of Inheritance to Multiple Genes Task E1: Worksheet 5a: Extending the Simulation Activity to Two Genes When you tried to apply the results of your 1 gene simulation activity to the design challenge, you realized that in order for the gecko to be rare, it would need to have more than one trait. Therefore, you need to extend your model of inheritance to include more genes. In order to help you do this, you are going to extend each of your tools (simulation activity, pedigree, egg/sperm chart, mathematical equation) to two genes to see what changes, if any, need to be made. You are going to start as you did in one gene with the simulation activity. Remember, you have the following resources available to you: a. Pictures A and B b. Inheritance Rules c. Model of Inheritance for One Gene d. The activity materials 1. Two paper geckos (one male and one female) 2. Two bags of shapes (one for each gecko) 3. Two bags of gametes (A gamete is a generic term for egg and sperm: eggs for the female gecko and sperm for the male gecko) Before You Start: Making sense of the simulation materials 1) Circle the zoom level(s) you are working at. DNA Gene 1 Allele 1 Allele 1 Gene 2 Allele 2 Allele 2 2) Each person should take one bag of shapes and keeping them separate dump them out on the desk. a. What is the genotype of parent 1? What is the genotype of parent 2? b. How are different genes represented? How do you know? Name Understanding Inheritance Teacher Date Task E: Extending the Model of Inheritance to Multiple Genes Task E1: Worksheet 5a: Extending the Simulation Activity to Two Genes c. How are different alleles for each gene represented? How do you know? Making the Prediction 3) Write down the cross that is being performed in this simulation activity: a. If these parents were to have 16 offspring, write down the different allele combinations you would expect to see and how many offspring will have each allele combination. Allele Combinations Number of Offspring with that Allele Combination Part I: Procedure for Putting Alleles in Eggs and Sperm 4) Write down the step(s) you will take to put alleles in eggs and sperm. STEP JUSTIFICATION (Inheritance Rule or Information from Picture A or B) Name Understanding Inheritance Teacher Date Task E: Extending the Model of Inheritance to Multiple Genes Task E1: Worksheet 5a: Extending the Simulation Activity to Two Genes 5) Follow that step for all the gametes (eggs or sperm) you have. a. Fill out the Eggs and Sperm Table to show what types of eggs and what types of sperm your geckos will produce: EGGS Summary of Class Discussion SPERM Name Understanding Inheritance Teacher Date Task E: Extending the Model of Inheritance to Multiple Genes Task E1: Worksheet 5a: Extending the Simulation Activity to Two Genes Evaluation of your prediction 6) Write down the allele combinations you saw in the offspring. a. Were your predictions about the types of allele combinations expected in the offspring supported by the simulation or not? How do you know? b. Were your predictions about the number of offspring with each allele combination supported by the simulation? Why or why not? i. What difficulty with your thinking caused your predictions to be inaccurate when you made them? ii. What have you learned that will help you make better predictions in the future? Name_______________________________Teacher________________Date________ Understanding Inheritance of Flower Color 1) Let’s look at plants to extend our examination of how alleles control the traits of an organism. Sweet Peas Crossed with… Produces… Female (Red) Offspring (Red) Male (White) Crossed with… Produces… Snap Dragons Crossed with… Produces… Female (Red) Male (White) Offspring (Pink) Inheritance of Flower Color Review the flower crosses on the previous pages. Test out the guidelines you have developed and your understanding of genetics by predicting the genotypes and phenotypes of the offspring between a cross of two heterozygotes for each type of flowrt. Show your predictions using a pedigree. Don’t forget to show the proportions of each genotype and phenotype. Camellia Sweet Pea Snap Dragon Name_______________________________Teacher______________________Date____________ Understanding Inheritance TASK F: Refining the Multigene Model by Connecting Genotype to Phenotype Task F2: Worksheet 6b: Applying the multi-gene model 2) Below is an outcomes pedigree showing the genotypes of a variety of mustard plant. Plants often produce many offspring. The following pedigree shows the outcomes of a cross that produced 200 offspring. The colors represent the phenotype of the plants; square alleles code for stem color and circle alleles code for leaf color. For example, plant 1a has a purple stem with yellow leaves. A pictorial representation of the plants is shown here: Name_______________________________Teacher______________________Date____________ Understanding Inheritance TASK F: Refining the Multigene Model by Connecting Genotype to Phenotype Task F2: Worksheet 6b: Applying the multi-gene model a. Which allele is dominant and which is recessive for each gene? Explain how you know. b. On the diagram above, complete the pedigree for the cross between 2d and 2e, showing the genotypes, phenotypes, and expected proportions for the offspring. 3) Scientists often use letters, instead of symbols, to represent alleles because it is faster than drawing symbols. The standard way of doing this is to select the first letter of the dominant trait and capitalize it; the recessive allele is the same letter but non-capitalized. For example, a gene for plant height could be represented as T (tall; dominant allele) and t (short; recessive allele). a. Using the conventions discussed above, write the letter that represents the allele in the table below. Gene (Symbol) Square Square Circle Circle Allele (Symbol Color) Black White White Black Color Purple stems Dark green stems Light green leaves Yellow leaves Allele Letter b. Write the genotype of the double heterozygous offspring from the cross between 2d and 2e using only letters. What proportion do you expect of this type and why? Support your answer using an equation and/or an egg and sperm table. Name_______________________________Teacher______________________Date____________ Understanding Inheritance TASK F: Refining the Multigene Model by Connecting Genotype to Phenotype Task F2: Worksheet 6b: Applying the multi-gene model 4) Suppose you want to breed a blizzard gecko that has six toes. You know that the blizzard allele is recessive to the normal allele for color, and that the allele for six toes is dominant to the allele for the normal number of toes. (Note: Always assume simple dominance unless otherwise specified). Using either symbols or letters: a. Write the genotype(s) for a blizzard 6-toed gecko. b. Write the genotype(s) for a blizzard gecko. c. Write the genotype(s) for a normal gecko. d. Name one cross that would produce a blizzard 6-toed gecko. Support your work with a pedigree, egg and sperm table, or equation. 5) You want to perform the following cross:  X  a. How many allele combinations are there in the offspring? Show how you figured this out. b. What proportion of the offspring will you expect to be triple homozygous black ()? Show how you figured this out. Name_______________________________Teacher______________________Date____________ Understanding Inheritance TASK F: Refining the Multigene Model by Connecting Genotype to Phenotype Task F2: Worksheet 6b: Applying the multi-gene model c. If the question in 5b had asked, “What is the probability that an offspring will be triple homozygous black?” would your answer from above change? Why or why not? “Gecko Breeding Challenge Final Design” With an understanding of genetics and inheritance you will design your final breeding plan to produce a rare Gecko. You will present your breeding plan to produce the rare geckos on a poster. You can choose three Geckos to purchase from the list below. The poster will contain the following information: 1. Your Names/Teacher’s Name/Date 2. An introductory paragraph which contains the following information: a. What type of gecko you are planning to breed and why. b. A 3-5 sentence summary of your plan for obtaining that gecko. 3. Which geckos you will buy initially and why. 4. For each cross that you make, you will include the following information. a. The geckos you are planning to mate. b. The verbal/biological rationale for doing that cross. c. The mathematical rationale for doing that cross. (This should include a prediction of the types and amounts of offspring.) Show your work! 5. For crosses which involve fewer than three genes, pictorial representation consisting of a sperm/egg table and a prediction pedigree showing both genotypes and phenotypes. 4. A summary paragraph for why the zoo should select your group. Your argument should be supported by EVIDENCE from the poster presentation of the breeding plan.” *Note that each of the six genes is separate. The genotype listed applies for all six genes. So a homozygous Albino lizard is homozygous for the Albino gene and normal homozygous for all other genes. Type of Leopard Gecko Picture Gene Recessive or Homozygous or Dominant Heterozygous Normal N/A N/A Homozygous or Heterozygous (for any other trait of interest) Albino Albino Recessive Homozygous Blizzard Blizzard Recessive Homozygous Patternless Patternless Recessive Homozygous Mack Snow Mack Codominant Heterozygous Super Mack Snow Mack Codominant Homozygous Enigma Enigma Dominant Homozygous or Heterozygous Giant Looks like Normal, but bigger. Giant Codominant Heterozygous Male: 90-109g in first year of life Female: 80-89g in first year of life Supergiant Looks like Normal, but bigger. Codominant Homozygous Male: More than 110g at 1 year old Female: More than 90g at 1 year old Weights for all geckos other than Giant and Supergiant: Male: 70-90g (as adult) Female: 50-70g (as adult)