Genetics Practice

Homework #3 Genetics practice problems: Name: Key ****Remember to ALWAYS: 1. list alleles and traits for each problem ex: B=Black b=brown 2. list parental genotype 4. Write genotypic ratio 3. list possible gametes 5. Write phenotypic ratio Part: 5 Incomplete Dominance heterozygotes are a BLEND!! ANSWER THE QUESTION 1. In radishes, red and white are pure-breeding colors, while hybrids are purple. If a red radish is crossed with a white radish, what will be the phenotype of the Fz generation (assuming the F₁ generation self- pollinates)? Show the Punnett Square Red RR Squa White Ww Purple-Rul WW P1= F RR X WW red x white < Gero RR:RwiWW = 0:40 phond Red Peuple white=04:0 F-100% purple FI generation Gero RR RW ww = Pheno: Red purple white = Fi cross RWxRW R W F2 generation gono-RR RW wiw=1:2:1 WRW WW phero Red preples while = 1:2:1 F2 50% purple 25910 Red 25% whete 2. In snapdragons, flower color is controlled by incomplete dominance. The two alleles are red (R) and white (W). The heterozygous genotype is expressed as pink. a) What is the phenotype of a plant with the genotype RR? Red b) What is the phenotype of a plant with the genotype Ww? white c) What is the phenotype of a plant with the genotype RW? Pink 3. A pink-flowered plant is crossed with a white-flowered plant. Show the Punnett Square. What is the probability of producing a pink-flowered plant? 50% RWX WW Pink white ww geno RRI RW ww 02:2 Pheno red pink whale = 02:2 50810 PINK 50% whirle 4. What cross will produce the most pink-flowered plants? Show a punnett square to support your answer. I think a red x white. RRX WW ww RRORU RRWRD 10010 RW= pink 5. In Andalusian fowls, black individuals (B) and white individuals (W) are homozygous. A homozygous black bird is crossed with a homozygous white bird. The offspring are all bluish-gray. Show the cross as well as the genotypes and phenotypes of the parents and offspring. BB-Black ww= white genotype = 100% BW= bluegies BBW BW BBW BW BW- Bluegray 6. What are the genotypic and phenotypic ratios if a black individual is crossed with a bluish-gray individual? Show the Punnett Square. BBX BW Black grey BW 50% Black SoPro Bluegray no BB:BW11000-22:0 preno Black gray whole 22:0 BBB BW 7. If two bluish gray individuals were crossed, what would be the ratios for both phenotype and genotype of the offspring? Show the Punnett Square. BWXBW geno=112:1 pheno: 1Black: Zgrag / wide BW BBBEW WBW WW 25% Black 50% Bluegray 25% whirte Co-Dominance Heterozygous have BOTH TRAITS!! 8. In some chickens, the gene for feather color is controlled by codominance. The allele for black is B and the allele for white is W. The heterozygous phenotype is known as erminette (black and white spotted). a) What is the genotype for black chickens? b) What is the genotype for white chickens? WW c) What is the genotype for erminette chickens? Bu B 9. Two erminette chickens were crossed. Show the Punnett square. a) What's the probability they would have a black chick? 25% b) What's the probability they would have a white chick? 25% BW BBB BW BW X BW Bhetidele Black white BBBWWw=12.1 Black Black Whale = 12:1 10. A black chicken and a white chicken are crossed. Show the Punnett Square. What is the probability that they will have erminette chicks? 100% BBX WW ww BBW B BBW B Part 6 Multiple Alleles This problem has multiple alleles AND they are co-dominant. 11. Two parents think their baby was switched at the hospital. Its 1968, so DNA fingerprinting technology does not exist yet. The mother has blood type "O." the father has blood type "AB," and the baby has blood type "В.", 0=ii doublerecessive a. Mother's genotype: b. Father's genotype: II c. Baby's genotype: I or I d. Punnett square showing all possible genotypes for children produced by this couple e. Was the baby switched? A I I Qii IIB A iLi IB II No-Baby had 50810 chance Being either typ Tipe A type B 12. Based on the information in this table, which men could not be the father of the baby? Justify your answer with a Punnett square. Name Blood Type Q=IBIA OKI Mother Type A Baby IB IB Baby Type B Type O Sammie i i George II's -50 NO Type B poss We - No Type B waitu IIP I Sammy the player Type AB George the sleeze The waiter Type A ② cable IBI of I-possible e 2 options The cable guy A Type B 2 QIAli IA B B A Could NOT Be O Sammy+ waiter. 25010 250