Final answer:
All types of listed genetic variation can contribute to differences in drug metabolism, which includes protein-coding genes, pleiotropic effects of genes, and DNA segments that regulate gene expression. This falls under the study of pharmacogenomics.Hence, the correct answer is option 4.
Step-by-step explanation:
The types of genetic variation that might contribute to differences in how individuals metabolize drugs are:
- Variation among individuals in alleles for protein-coding genes
- Variation among individuals in the pleiotropic effects of genes
- Variation among individuals in the segments of DNA that influence gene expression
Hence, the correct answer is 4) All of the above are types of genetic variation that may affect how individuals metabolize drugs. Variants in protein-coding genes can directly change the enzymes responsible for metabolizing drugs. Pleiotropic effects mean that a single gene may influence multiple traits, including how a drug is metabolized. Segments of DNA that regulate gene expression can also impact the levels of enzymes available to metabolize drugs.
Pharmacogenomics is the study of how genetic variation affects individual responses to therapeutic drugs, which includes understanding how enzymes involved in drug metabolism, like those coded by the CYP genes, are influenced by variations in an individual's genetic code.