Genetics HW 1 Group Number_ 7

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Group Number: 7 Group members’ names and signatures: Mossimo Tampol, Benjamin Khaim, Nina Peros, Anna Zou 1. A DNA fragment has 23% nucleotides with the base A. What is the percentage of the nucleotides with the base G, T, and C? Show your calculations. (10 points) The bases A and T will both have 23% nucleotides, while G and C bases will both have 27% 23% + 23% = 46% → 100% - 46%= 54% → 54%/2 = 27% 2. Use your own words to describe the central dogma. Please include in your answer DNA, RNA, protein, transcription, and translation. (15 points) The central dogma of molecular genetics emphasizes that genetic information can only flow in one direction from DNA to protein. DNA holds the information needed for protein synthesis, and the dogma explains the intermediate steps that occur. Initially, it was only a theory but was later confirmed through experimental efforts. Genetic information begins in DNA, and from there, it is transferred to various RNA intermediates through the process of transcription. The DNA’s information can be transcribed into rRNA, mRNA, or tRNA. The mRNA is responsible for carrying genetic information from DNA, which allows it to serve as a template in protein synthesis. rRNA are components of the ribosomes on which proteins are synthesized. Lastly, tRNA is responsible for carrying amino acids to be added to the polypeptide chain. After transcription (DNA→RNA), the RNA aids in the flow of info from RNA→protein formation. 3. Flower color. You have isolated two true-breeding snapdragon plants. Both have white colored flowers, as opposed to the normal purple flower color. You know that each plant carries a recessive mutation that affect flower color. a). What test would use to find out whether the two mutations are in the same gene? Please only give the name of the test. (5 points) - Complementation Test b). Let’s use m1 to represent one of the mutations, and m2 to represent the other mutation. What do you expect the result to be if the mutations are in the same gene? What do you expect if they are in different genes? Please use a diagram to show the reasoning behind your answer. (15 points) If the m1 and m2 mutations are on the same gene, you can expect the progeny to appear as a mutant because the mutations will not complement each other. However, if the mutations are on different genes they will complement each other, and the progeny will appear as a wild-type.

c). Let’s assume these two mutations are in two different genes. It turns out at least one functional copy of these two genes are required to make the purple color. In a dihybrid cross between these two white-flowered plants, what do you expect the phenotypes of F2s to be? And what are their proportions? Show your work. (15 points) Phenotypes of F2: white-flowered plants and purple-flowered plants 16:7 CP cp Cp cP CP CCPP CcPp CCPp CcPP cp CpCp cpcp Ccpp ccPp Cp CCPp Ccpp CCpp CcPp cP CcPP ccPp CcPp ccPP 4. Short-tailed pup distribution. In mice, the dominant T allele results in a short tail. Homozygous T/T genotype is lethal, which means mouse embryos with this genotype die before they are born. Homozygous t/t is normal, with normal tail. A cross between two short-tailed mice produces a litter of 5 pups. a). What are the genotype(s) of the two short-tailed mice used in the cross? (10 points) - The genotype would be Heterozygous T/t

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