Genetics Review .com



Genetics ReviewUsing white boards, answer the following questions. You will not be able to move on to the next section/question, until I have checked the previous section/question.Part A: VocabularyFor each of the following sets of terms, write a sentence or a short paragraph that uses each word correctly and explains how the terms are related.Example: Gamete, egg, spermGametes are cells that are specialized for reproduction. A male’s gametes are sperm; a female’s gametes are eggs.Homologous chromosomes, gene, allelesGenotype, homozygous, heterozygousDominant, recessive, incompletely dominantX chromosome, Y chromosome, male, female, sex-linked trait. Fill in the blank with the allele(s) that best fits the description.IBtTTRrFXC1. _______________ a recessive allele2. _______________a homozygous dominant allele pair3. _______________a co-dominant allele4. _______________ a dominant allele5. _______________a heterozygous allele pair6. _______________an allele on the X chromosomePart B: Punnett Squares & PedigreesWhat Colour is the Pod? Green (G) is the dominant colour for pods of pea plants. Yellow (g) is recessive.What are the phenotypes of the following genotypes if this trait shows complete dominance?GGGggg Complete Punnett squares to show the outcomes of the following crosses.GG x GgGG x ggGg x GgGg x ggPure Gold? Imagine that you have inherited a ranch in California from a distant relative. When you visit the ranch, you instantly fall in love with several magnificent palomino horses. The palominos are golden in colour. They have blonde tails and manes. You decide to breed the palominos.How could you determine experimentally if the palomino colour is a hybrid or a purebred trait?Suppose that you bred many pairs of palomino horses and they produced these foals: 61 palomino, 32 brown, 29 whiteDoes this observation support the hypothesis that palomino colour is purebred? About what percentage of the foals were palomino? Brown? White?When the foals mature, you breed the brown horses together. All the resulting foals are brown. You also breed the white horses together. All of their foals are white. Represent the genotype of brown horse as BB and white horses as bb. Complete a Punnett square to show the mating of two golden palomino horses. What genetic inheritance is demonstrated in this example? A Quick Switch?In the maternity ward, Mrs. Bright and Mrs. Light shared a room. When they were ready to go home, Mrs. Bright insisted that she had been given the wrong baby. The babies looked very much alike, and unfortunately, no one could find a record of the babies’ footprints. Hospital officials told Mrs. Bright that she was mistaken and sent her and the baby home. Mrs. Bright eventually asked the hospital to perform identification tests. Several weeks later, blood tests showed the following data:Mrs. BrightGroup ABMrs. LightGroup AMr. BrightGroup OMr. LightGroup ABaby at Bright’s houseGroup OBaby at Light’s houseGroup AWhat is Mrs. Bright’s phenotype? What possible genotypes can Mrs. Bright have?What is Mr. Bright’s phenotype? What possible genotypes can Mr. Bright have?Using a Punnett square, show the possible blood genotypes of a child born to the Bright’s.What is Mrs. Light’s phenotype? What possible genotypes can Mrs. Light have?What is Mr. Light’s phenotype? What possible genotypes can Mr. Light have?Using 3 Punnett squares, show possible genotypes of a child born to the Light’s. Was there a mix-up of babies at the hospital? Explain.Can You See What’s Happening Here?A colour-blind man marries a woman with normal vision. Of their three daughters, one is colour-blind. One of their two sons is also colour-blind. Draw a pedigree to show the inheritance pattern. What are the genotypes of the all individuals in the family? Reading a Human PedigreeA human pedigree can be used to trace the inheritance of sickle cell anemia through several generations of a family. The pedigree below traces the pattern of inheritance of sickle cell anemia.18796009207500-520701111250070695867945UnaffectedAffectedCarrier00UnaffectedAffectedCarrierHow many generations are shown on the pedigree?Which parent in the first generation had sickle cell anemia?How many children were born in the second generation?How many of these children are carriers of sickle cell anemia?How many children in the third generation have sickle cell anemia? How many are carriers?Is sickle cell anemia a sex-linked trait? How can you tell?Is the gene for sickle cell anemia more likely to be dominant or recessive? Explain.Genetics Review Answer KeyPart A: VocabularySet of Terms:Homologous chromosomes, gene, allelesHomologous chromosomes are chromosomes that have the same genes in the same locations. Alleles are the different forms of the gene that are found on the chromosome. Genotype, homozygous, heterozygousAn organism’s genotype is based on the pairs of alleles that they have. If the alleles are the same they are homozygous. If the alleles are different they are heterozygous.Dominant, recessive, incompletely dominantA trait is incompletely dominant if an organism has one dominant copy and one recessive copy but shows an intermediate form of the trait. X chromosome, Y chromosome, male, female, sex-linked trait.Males have an X chromosome and a Y chromosome. Females have 2 X chromosomes. Most sex-linked traits are found on the X chromosome. t = a recessive alleleTT = a homozygous dominant allele pairIB = a co-dominant alleleF = a dominant alleleRr = a heterozygous allele pairXC = an allele on the X chromosomeGenetics Review Answer KeyPart B: Punnett Squares and PedigreesWhat Colour is the Pod?GG - greenGg - greengg – yellow GG x Gg GG x ggGGGGGGGGGgGgGggGgGggGgGg Gg x GgGg x ggGgGgGGGGggGggggGggggGgggGenetics Review Answer KeyPart B: Punnett Squares and PedigreesPure Gold?Cross-breed palomino horses and see if any of the offspring are a different colour.No, it does not support the hypothesis because some of the offspring are colours other than palomino. Palomino – 50%, Brown – 25%, White – 25% Palomino – BbBbBBBBbbBbbbIncomplete dominanceGenetics Review Answer KeyPart B: Punnett Squares and PedigreesA Quick Switch?Mrs. BrightPhenotype = Type AB, genotype = IAIBMr. BrightPhenotype = Type O, genotype = iiIAIBiIAiIBiiIAiIBiMrs. LightPhenotype = Type A, genotype = IAIA or IAiMr. LightPhenotype = Type A, genotype = IAIA or IAi Option 1: IAIA x IAIA Option 2: IAIA x IAi Option 3: IAi x IAiIAIAIAIAIAiIAIAIAIAIAIAIAIAIAIAIAIAIAIAiIAIAIAIAIAiIAiIAiiIAiiiYes, because the Brights can only have a baby with Type A or Type B blood, but the Lights could have a baby that is either Type O or Type A. Genetics Review Answer KeyPart B: Punnett Squares and PedigreesCan You See What’s Happening Here?337185013487410436245013487400188214029273502540001591310XBXb020000XBXb13754101598930XBXb020000XBXb22898101590675XbXb020000XbXb32473901607820XBY020000XBY41973501598367XbY020000XbY25786757620XBXb020000XBXb1716405-1270XbY020000XbY246380013417551515110135001043688013417552576195884555347281588455544557958756651652270884555556895883920560477878780243264942199920875684219992717321266724Genetics Review Answer KeyPart B: Punnett Squares and PedigreesReading a Human Pedigree4 generationsMale (father)3 childrenAll 3 are carriersAffected = 1, carriers = 3Not sex-linked because equally distributed between males and females.Recessive because trait skips generations in terms of individuals who are affected. Gene is passed on to most offspring in carrier form (unaffected).Need two copies to show trait. ................
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