Mendelian Genetics

Assignment #1: Mendelian Genetics This assignment is affiliated with the 8Assignment #1: Mendelian Genetics= quiz on the folio course page. Complete the following problems before attempting the quiz as you will only have one attempt at the quiz and there will be a 25 minute time limit. The answers to these questions, questions concerning methodology, along with 1-2 new problems (with similar mechanisms to solving those problems) are all potential quiz questions. You must complete the quiz prior to midnight Sunday, Aug. 26. 1a) The summer squash has a white fruit color which is dominant over yellow fruit color. If a white fruit homozygous plant is crossed with a homozygous yellow fruit plant, what will the genotype of the first generation (F1)? C = White coloring; c= Yellow coloring CC crossed with cc C C c Cc Cc c Cc Cc The genotypes of the F1 generation will all be heterozygous (Cc). 1b) If the individuals from the F1 generation were allowed to fertilize one another, what is the expected genotypic and phenotypic ratios? All F1 generation must be Cc C c C CC Cc c Cc cc The expected genotypic ratio would be 1:2:1 while the phenotypic ratio would be 3:1 2a) In the high pressure, deep, dark depths of the ocean9s abyssal plains lives an organism called a viper fish. These fish resemble transparent eels with overlarge heads and very long, pointy teeth. Some of these fish can produce biochemical luminescence along the length of their bodies and some cannot. Also, some have very large eyes while others have almost no eyes at all. Assume that these two traits are each controlled by single separate genes with the production of bioluminescence (L) and large eyes (E) being dominant alleles for those traits. A female fish heterozygous for both traits happens to meet a male that is homozygous dominant for bioluminescence and homozygous recessive for eyes. List all the possible genotypes of their offspring. Possible genotypes: LLEe, LLee, LlEe, Llee 2b) What are the odds that any progeny will be bioluminescent with no eyes? Mother = LlEe Father = LLee Le Le Le Le LE LLEe LLEe LLEe LLEe Le LLee LLee LLee LLee Bioluminescent along length of their bodies and no eyes (LLee or Llee) = 50% lE LlEe LlEe LlEe LlEe Le Llee Llee Llee Llee 3a) Arctic Ptarmigans live across the sea ice along the Arctic coast and have several physical adaptations which make it easier to traverse the snow and ice. They have very wide feet fully covered with feathers which help them maintain balance and reduce heat loss while standing on ice. Some also grow a seasonal set of feathers which are entirely white to help them camouflage themselves while on the snow/ice. Assume the wide feet with feathers (W) and camouflage (C) are both dominant traits. Suppose that a female with both dominant traits mates with a male that is heterozygous for both traits. What is the probability that a single offspring would not express either dominant trait? Father = WwCc Mother = WwCc (only option for phenotype if child to express no dominant traits); other 3 potential maternal phenotypes (WWCc; WwCC; WWCC would lead all progeny to express at least one dominant allele). WC WWCC WWCc WwCC WwCc WC Wc wC Wc Wc WWCc WWcc WwCc Wwcc wC WwCC WwCc wwCC wwCc wc WwCc Wwcc wwCc wwcc Chances a single offspring would not express either dominant trait = 1/16 * ¼ chance that mother is the heterozygous phenotype = 1/64 = 0.016% 3b) What is overall probability that a single offspring would be heterozygous for both traits (remember that you do not know the exact genotype of the mother)? Father = WwCc Offspring: WwCc Mother: WwCc = ½ * ½ = ¼ WWCc = ½ * ¼ = ¼ WwCC = ½ * ½ = ¼ WWCC = ½ * ½ = ¼ Regardless of the mother9s phenotype, there is ¼ (25%) that a single offspring would be heterozygous for both traits. 4) Suppose you have a bunch of white mice, some that solid white and some with black spots. Additionally, some mice have black eyes while others have pink eyes. Assume solid white (W) is dominant to black spots and black eyes (B) are dominant to pink. You decide to cross a female that is homozygous dominant for hair color and heterozygous for eye color with a male that is heterozygous for both traits. If the breeding leads to 32 pups, how many would you expect to have solid white fur and pink eyes? Male = WwBb Female = WWBb Looking for young with genotype expressing W and bb. WB Wb wB wb Total is 4/16 = 25% 25% * 32 pups = 8 pups WB WWBB WWBb WwBB WwBb Wb WWBb WWbb WwBb Wwbb WB WWBB WWBb WwBB WwBb Wb WWBb WWbb WwBb Wwbb 5a) Pepper moths can have one of two body colorations, dark and speckled. The dark coloration (C) is dominant over the speckled (c). Additionally, the moths can either have long (A) or short (a) antennae where long is dominant over short. Finally, the moths wings can be rounded (BB), straight (Bb), or stunted (bb). If two moths with the following genotypes (AaBbCc x AabbCC) mated, what are the odds that their progeny would be dark with long antennae and straight wings? P1: AaBbCc x AabbCC Chances of AaBbCC: 0.5 * 0.5 * 0.5 = 1/8 = 2/16 Chances of AaBbCc: 0.5 * 0.5 * 0.5 = 1/8 = 2/16 Chances of AABbCC: 0.25 * 0.5 * 0.5 = 1/16 Chances of AABbCc: 0.25 * 0.5 * 0.5 = 1/16 TOTAL ODDS: 6/16 = 3/8 5b) What are the odds that any progeny from this matting will be homozygous recessive for exactly two of the three genotypes? Chances of aabbCc: 1/4 * 1/2 * 1/2 = 1/16 Chances of aabbCC: 1/4 * 1/2 * 1/2 = 1/16 Total odds: 1/16 + 1/16 = 2/16 = 1/8 = 12.5%