3. If a heterozygous fire-breathing dragon is crossed with one that does not breathe fire, how many offspring will be fire breathers?

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1 Mrs. Davisson Name Chapter 11: Genetics Per. Row Part I. Monohybrid Crosses - Complete Dominance For each of the following genetics problems, follow these steps in reaching a complete answer: Show all work. Use pencil. a) State parental cross. b) Set up a proper punnet square (male genes on top; female genes on the side) c) Complete all punnet square combinations. d) Do a genotype and phenotype analysis. e) Give a ratio for genotype and phenotype when needed. f) Answer any specific questions as stated in the genetics problem. Example: Tallness is dominant over shortness. Cross: Hybrid tall X Pure short Let T = gene for tallness. Let t = gene for shortness. Parents Tt X tt Genotype: 1/2 Tt;1/2 tt Genotype Ratio: 0:1:1 Gametes T t & t t Phenotype: 50% tall; 50% short Phenotype Ratio 1:1 1. Round seeds (R) are dominant over wrinkled seeds (r). Cross: Pure round seeds X Pure wrinkled seeds If these two plants had 100 seeds, how many would you expect to be round?, wrinkled?. Dragon Genetics: Show punnet square and answer question 2. In dragons, the allele for fire breathing is dominant. Dragons can be fire breathers, or non-fire breathers. Show the genotypes and phenotypes of all possible dragons. 3. If a heterozygous fire-breathing dragon is crossed with one that does not breathe fire, how many offspring will be fire breathers? 4. If two heterozygous dragons are crossed, how many offspring would you expect to NOT be fire-breathers? 5. Also in dragons, wings are a dominant trait. If you crossed two wingless dragons, how many of their offspring would you expect to have wings? 6. Two winged dragons produce an offspring that does not have wings. What are the genotypes of the parents? 7. If a purebred winged dragon is crossed with a purebred wingless dragon, how many of their offspring will be winged and what is their genotype? Part II. Codominance & Incomplete Dominance Incomplete dominance: Neither allele is completely dominant over the other allele- there will be blending between the two traits. Codominance is a condition when both alleles are dominant and both are expressed at the same time. 1. If a black Andalusian fowl (BB) is crossed with a white Andalusian fowl (bb), all the offspring come out blue (Bb)- (really a combination of black and white feathers). Cross: White Andalusian hen X Blue Andalusian rooster Circle one: Incomplete Dominance or Codominant? If these two birds had 20 offspring, how many would you expect to have white fur? 1

2 2. In four o clock flowers, pink flowers result from a cross between a red flowered and a white flowered parent. a) Cross: red flowered X white flowered (parental cross). Circle one: Incomplete Dominance or Codominant? b) After you do the parental cross then do another cross between cross two F1 generation offspring. If these two plants had 100 seeds, how many would you expect to be pink? Dragong Genetics: Codominance and Incomplete Dominance 3. Dragon Eyes can be yellow, blue, or green. Is this codominance or incomplete dominance? 4. What is the chance that two green eyed dragons will have offspring with yellow eyes? 5. a. Dragon spins can be red, blue, or a mix or red and blue. Is this codominance or incomplete? b. A red spined dragon and a blue spined dragon have offspring. What color are the babies' spines? 6. A red spined dragon and a mixed spined dragon are crossed. How many of their babies will have red spines? 7. What if a red spined dragon that CANNOT breathe fire is crossed with a blue spined dragon that can breathe fire but his mother could not? Part III. Dihybrid Crosses- crossing two traits at the same time. **When doing a phenotype ratio for a dihybrid cross you MUST put it on the proper order: dominant/dominant ; dominant/recessive ; recessive/dominant; recessive/recessive Example: 9 ; 3 ; 3 ; 1 1. In pigs, T = curly tail B =brown coat t = straight tail b = white coat Complete dominance Complete dominance Show the results of the following crosses: a. TtBb x TtBb What percentage of the offspring will be purebred dominant for both traits? 2

3 b. TTbb x ttbb 2. In pea plants, long stems are dominant over short stems. Green pods are dominant over yellow pods. A homozygous long-stemmed, yellow-podded plant is crossed with a homozygous short-stemmed, green-podded plant. Use your own system of letters and a Punnet square to show the possible genotypes and phenotypes of such a cross. 3. In fruit fly Drosophila, vestigial wings(ww) and hairy body(hh) are produced by two recessive genes located on different chromosomes. The normal alleles, long wings(ww), and hairless body(hh) are dominant. Suppose a heterozygous long winged, hairy male is crossed with a female that is homozygous for long winged and heterozygous hairless. What percentage of the offspring will have long wings and hairless bodies? Dragon Genetics: Crosses that Involve 2 Traits (Dihybrid) 4. A winged dragon (Gg) that breath fire (Ff) is crossed with one that is wingless and cannot breath fire. How many of their offspring will be winged fire breathers? 5. A fire breathing winged dragon (GgFf) is crossed with one that is winged and cannot breath fire (Ggff) How many of the offspring do not have wings and cannot breath fire? 6. So little Spyro has wings and can breath fire. He does not know his genotype. How can Spyro find out his genotype? Answer: THE TEST CROSS Describe how you would set up the test cross: 3

4 Part IV. Multiple Alleles- more than two alleles in the population for a genetic trait. The following information is used to describe the possible genotypes and phenotypes of blood. Alleles A and B are codominant and allele O is recessive. *The genotypes AA and AO produce the phenotype: Type A blood. *The genotypes BB and BO produce the phenotype: Type B blood. *The genotype AB produces the phenotype: Type AB blood. *The genotype OO produces the phenotype: Type O blood. The Case of the Long-Lost Son Mr. Cash died and left all his money to his two children. A young man claiming to be a lost third child sued for his share of the estate. The judge ordered blood tests for all family members and for the young man. Mr. Cash s blood type was AB. His wife had type A blood. 2. Using a Punnett square, diagram the offspring that could be produced if Mrs. Cash had genotype AA and Mr. Cash had genotype AB. 3. Which phenotypes could result among the offspring of this marriage? 4. Using another Punnett square diagram the possible offspring if Mrs. Cash had genotype AO and Mr. Cash had genotype AB. 5. Which phenotypes could result among the offspring of this marriage? ** The man claiming to be the long-lost son then went for his blood test. He had type O blood. 6. What is the genotype of the young man claiming to be Mr. Cash s long lost son?_ 7. Could this young man have been Mr. Cash s son? 8. What is an allele? 9. How many alleles are there in the population for blood type? List these alleles: _ 10. How many alleles does each person have for blood type?_ 11. Suppose two newborn babies were accidentally mixed up in a hospital, something that rarely happens. In an effort to determine the parents of each baby, the blood types of the parents and the babies were determined. Which baby belongs to which parent? What is the actual genotype of each parent and baby? Baby 1-type A Mrs. Davisson-type B Mrs. Lantz-type O Baby 2-type O Mr. Davisson-type O Mr. Lantz-type AB Name Mrs. Davisson Mr. Davisson Mrs. Lantz Mr. Lantz Baby 1 Baby 2 Genotype Which baby belongs to Mr. & Mrs. Davisson? Which baby belongs to Mr. And Mrs. Lantz? Dragon Genetics Multiple Alleles Dragons have three main alleles for colors: black, red, and green (similar to blood type). Green is the most recessive. When black and red are codominent to each other, creating a black and red dragon, but both are dominant over green. 12. Create a key for dragon color multiple alleles. 13. What would be the possible genotypes and phenotypes of the children of a black dragon whose mother was green, and a mixed black and red dragon. 4

5 Part V. Sex- Linked Inheritance- these genes are located on the sex (usually the X) chromosome. Ex: color blind, hemophilia, muscular dystrophy, ALD. 1. When a Color-Blind man marries a woman with normal vision what Genotypes and Phenotypes can occur in the children? What percentage of their boys will be expected to be colorblind? 2. If a hemophiliac man marries a woman who had a hemophiliac father, what Genotypes and Phenotype can occur in the children? What percentage of their girls will be expected to be hemophiliacs? 3. If a man with muscular dystrophy marries a woman with muscular dystrophy what Genotypes and Phenotypes can occur in their children? What percentage of their boys will be expected to have muscular dystrophy? 4. Examine the following pedigree chart for color vision and indicate the Genotypes and Phenotypes for each of the numbered individuals. 1. Genotype: ; phenotype: 2. Genotype: ; phenotype: 3. Genotype: ; phenotype: 4. Genotype: ; phenotype: 5. Genotype: ; phenotype: 6. Genotype: ; phenotype: 7. Genotype: ; phenotype: 8. Genotype: ; phenotype: 9. Genotype: _ or ; phenotype: or 10. Genotype: ; phenotype: 11. Genotype: ; phenotype: 12. Genotype: ; phenotype: Dragon Genetics Sex - Linked Traits 5. Not all dragons have ears, and it is considered an oddity in the dragon community. Ears are a sex linked, recessive trait. What would the possible genotypes of both male and female dragons? 6. A female dragon is a carrier for the ears trait. How many of her offspring will have ears? 5

6 7. A male dragon with ears is crossed with a female dragon who is a carrier. How many of their offspring will have ears? 8. A male dragon that is heterozygous for the winged trait also has ears. It is crossed with a wingless female dragon who is a carrier for ears trait. What are the possible offspring of this cross and in what proportion? Part VI. Genetics Vocabulary Practice 1. Pedigree 2. Genotype 3. Polygenic trait 4. Recessive 5. P generation 6. F1 generation 7. F2 generation 8. Heredity 9. Monohybrid cross 10. Alleles 11. Homozygous (Pure) 12. Heterozygous (Hybrid) 13. Genetics 14. Codominance 15. Incomplete dominance 16. Multiple alleles 17. Phenotype 18. Dominant 19. Punnett square 20. X-linked trait 21. Segregation 22. Independent assortment 23. Probability 24. Gamete 25. Gregor Mendel a. The alleles of a particular gene are different b. The two alleles for a trait separate when gametes are formed c. The alleles of different genes separate independently of one another during gamete formation d. Not expressed when the dominant form of the trait is present e. Passing of trait from parents to offspring f. Diagram that predicts the outcome of a genetic cross g. The expressed form of a trait h. First two individuals crossed in a breeding experiment i. Physical appearance of a trait j. A cross that considers one pair contrasting traits k. Offspring of the F1 generation l. When the two alleles of a particular gene are the same m. Branch of a biology that studies heredity n. Different versions of a gene o. Offspring of a P generation p. Set of alleles that an individual has q. Genes with three or more alleles r. The likelihood that a specific event will occur s. The Father of Genetics t. When an event displays a trait that is intermediate between the two parents u. Trait whose allele is located on the X chromosomes v. When several genes influence a trait w. Two dominant alleles are expressed at the same time x. A family history chart that shows how a trait is inherited y. Sex cell 6