Question about Antibiotics?
You observe that pathogenic bacterium X has evolved resistance to antibiotic Z but only in some patients. Careful data collection reveals that patients infected with resistant bacterium X are also infected with bacterium Y (r2 = 0.96) that is also resistant to antibiotic Z. You hypothesize that bacterium X has acquired its resistance to antibiotic Z from bacterium Y through horizontal gene transfer. Which evidence would refute this hypothesis? (Select all that apply.)
If you find a significant number of patients that possess Z-resistant bacterium X and Z-resistant bacterium Y.
If you find a significant number of patients that lack Z-resistant bacterium X and Z-resistant bacterium Y.
If you find a significant number of patients that possess Z-resistant bacterium X but no Z-resistant bacterium Y.