Question

Pathogenicity islands are blocks of genes on the bacterial chromosome that

most likely arose from this process.
A. Spontaneous mutation
B. Horizontal gene transfer
C. Vertical gene transfer
D. Chemically induced mutagenesis
E. Mutation via gamma radiation

Answer 1

Pathogenicity islands in bacteria commonly originate from horizontal gene transfer, a process that enables the sharing of genes such as those conferring antibiotic resistance or virulence, independent of reproduction.

Step-by-step explanation:

Pathogenicity islands are blocks of genes on the bacterial chromosome that likely arose from horizontal gene transfer. This is a process where genes can be passed between organisms in a manner other than traditional reproduction, such as transformation, conjugation, transduction, or gene transfer agents (GTAs).

These mechanisms allow for the transfer of genes that can confer attributes like antibiotic resistance, hence promoting the emergence of resistant bacterial strains or "superbugs." In the context of pathogenicity islands, this horizontal gene transfer often involves virulence factors that can turn a nonpathogenic bacterium into a pathogenic one.