Student Exploration: Chicken Genetics

Student Exploration: Chicken Genetics Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange boxes. Vocabulary: allele, codominance, dominant, genotype, heterozygous, homozygous, phenotype, probability, Punnett square, recessive, trial Prior Knowledge Questions (Do these BEFORE using the Gizmo.) 1. The image shows a flower that was produced by crossing a pure red flower with a pure white flower. Which do you think is the dominant petal color: red or white? Explain. (2 Marks) red as there is a much larger quantity Of that colour in this flower 2. How is the inheritance pattern shown by this flower different from other inheritance patterns you have seen or studied? (1 Mark) I can see that the flower has a mixture of its its from its parents traits parents. Most cover the flower would be one "Colour of the other, but it looks at there was a parent with both and white stars.car. Gizmo Warm-up There are many different ways traits can be inherited. Some traits are governed by alleles that are dominant over other alleles. Other traits are governed by alleles that share dominance. These alleles follow a pattern of inheritance called codominance. With the Chicken Genetics Gizmo, you will study how codominance affects the inheritance of certain traits. "Pure" chickens 1. Turn on Show genotype. The genotype is the allele combination an organism has. Point to the red chicken. (2 Marks) A. What is the red chicken's genotype? FR FR B. What is the white chicken's genotype? FW FW 2. What do you think the letters F, R, and W stand for in the genotypes? (1 Mark) F= Feathers R= Ded W= White Activity A: Get the Gizmo ready: Codominant traits Drag a red chicken and a white chicken into the parent boxes, but don't click Breed yet. Question: What inheritance patterns do codominant traits display? 1. Predict: What do you think the offspring of a red chicken and a white chicken will look like? (1 Mark) I think as the petals shown in the first picture, there will be a mixture in colour of feathers (1 Mark) 2. Observe: Click Breed. What are the offspring genotypes? Fefw An organism's appearance is its phenotype. Describe the offspring's phenotype. (1 Mark) The Offspring has red AND white Feathers 13. Experiment: Drag four offspring to the Holding Cages. Click Clear, and then drag one of the offspring to a parent box. Drag a white chicken to the other box. Click Breed several times. Describe the resulting genotypes and phenotypes of the offspring. (2 Marks) genotyper: Fere and FR FO phenotypes: Foll red feathers and Red/White feathers. لا 4. Revise and Repeat: Click Clear. Drag another chicken from the Holding Cages to the parent box. Drag a red chicken to the other box. Click Breed several times. Describe the resulting genotypes and phenotypes of the offspring. (2 Marks) genotypes: fwfw and FRFW White phenotypes: Full white feathers and Red lette offspring 5. Explain: In dominant/recessive inheritance patterns, the dominant allele is always expressed when present. The recessive allele is only expressed when the dominant allele is not present. Use your observations from this activity to describe how codominant inheritance patterns differ from dominant/recessive inheritance patterns. (1 Mark) Solid when the red feathers would be present but the whewhite A allele would not able to dendopes Solid red was not involved, then they would allow the white to appear in the off spring more often. neither of the alteler were more dominant you just need to choose which one gets mixed "with the 3rd phenotype (red/white) Activity B: Get the Gizmo ready: Click Clear. Codominant crosses Drag the remaining chickens from the Holding Cages into the parent boxes. Introduction: Probability is the likelihood that a specific event will occur. Scientists use probability to predict the outcomes of different genetic crosses. Question: How can you use probability to predict the outcome of a codominant cross? 1. Model: A Punnett square is used to model the possible offspring genotypes from a genetic cross. The parent genotypes are written at the top and side of the square, as shown. The possible offspring genotypes are then filled in. The first square is filled in for you. Fill in the remaining squares. (Note F ^ R * F ^ w is equivalent to F ^ (ij) * F ^ R .) (3 Marks) P ^ R P ^ R F ^ w Holding cag F ^ w F ^ 60 * F ^ 2 FOFW 2. Analyze: A homozygous chicken will have the same alleles for feather color. A heterozygous chicken will have two different alleles for feather color. A. Are the parents homozygous or heterozygous? Explain how you know. (2 Marks) heterozygous as they have 2 differ alletes for feather Colours which explains Realwhite colour B. What are the possible genotypes of the offspring? (1 Mark) FREW FREE Fofur C. Will the offspring be homozygous or heterozygous? (1 Mark) Both 3. Calculate: Punnett squares can be used to predict probable outcomes of genetic crosses. To calculate probability, divide the number of one kind of possible outcome by the total number of all possible outcomes. For example, if you toss a coin, the chance it will land on heads is equal to 1 + 2. This probability can be expressed as ½, 0.5, or 50%. Look at the Punnett square above. A. How many total possible outcomes are there? 3 (1 Mark) B. How many of the possible outcomes are there for each of the following genotypes? FR FR 25% ory FW FW 25% 07 1 FRFW 50% orz (