3.9: Review Questions

• What is the purpose of DNA replication? Explain in a few sentences what happens during DNA replication. When do DNA mutations happen? And how does this create phenotypic variation (i.e., different phenotypes of the same physical trait)?
• Using your own words, what are homologous chromosomes and sister chromatids? What are the key differences between mitosis and meiosis?
• Determine if the pedigree diagram below (Figure 3.41) represents an autosomal dominant, autosomal recessive, or X-linked recessive pattern of inheritance. You should write the genotype (i.e., AA, Aa, or aa) above each square to help you (note: there may sometimes be two possible answers for a square’s genotype). Please also explain why you concluded a particular pattern of inheritance.

Figure 3.41: A four generation pedigree depicting a trait with an undetermined inheritance pattern. Credit: X-linked recessive pattern of inheritance (Figure 3.46) original to Explorations: An Open Invitation to Biological Anthropology by Beth Shook is under a CC BY-NC 4.0 License.

• Use base pairing rules to transcribe the following DNA template sequence into mRNA: GTAAAGGTGCTGGCCATC. Next, use the protein codon table (see Figure 3.21) to translate the sequence. In regard to transcription, explain what the significance is of the first and last codon/protein in the sequence.
• In your opinion, what do you think the benefits are of direct-to-consumer (DTC) genetic testing? What are the drawbacks and/or greater ethical concerns? Do you think benefits outweigh concerns?
• Imagine that you submit your DNA sample to a genetic testing company and among the various diseases for which they test, there is an allele that is associated with late-onset Alzheimer’s disease. You have the option to view your Alzheimer’s result or to not view your result. What do you do and why?