1. Your roommate purchased a “direct-to-consumer” genetic test and now wants you
ID: 72333 • Letter: 1
Question
1. Your roommate purchased a “direct-to-consumer” genetic test and now wants your help understanding the results. (These genetic tests analyze DNA in consumer’s saliva to determine their genotypes for certain diseases. The consumer then receives a printout of the results.)
A. You roommate’s results indicate homozygous recessive for a gene related to caffeine metabolism. The wild-type gene codes for enzymes that metabolize caffeine; therefore, your roommate may have “caffeine sensitivity” due to slow metabolic rates. Explain to your roommate how genes affect the production of enzymes and how mutations can affect enzyme function.
Explanation / Answer
A gene mutation is a change in the sequence order of a gene as a result of which the synthesis of encoded protein from the concerned gene is altered and no longer function normally. Moreover, as per the Beadle and Tatum "the one gene-one enzyme hypothesis " the gene acts through the production of enzymes, and each gene responsible for producing a single enzyme. Thus, the mutation if any occurred at the gene level, it does affect the enzyme encoded by it.
The enzyme is the biological catalyst which boost up the biochemical reaction in our body. Furthermore, enzymes are substrate specific, which means that they bind to a substrate which fits to or complements to their active site. Mutation if any occurred related to the gene encoding the concerned enzyme, causes the modification of active site which make the enzyme no longer complementary to the active site of the substrate. Thus, the inability of the enzyme binding with substrate makes the concerned functionless.
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