Final answer:
Horizontal gene transfer (HGT) is the process by which bacteria acquire new genes outside of cell division through mechanisms like conjugation, transformation, and transduction. It is significant for the spread of antibiotic resistance among bacterial populations. The correct option is B.
Step-by-step explanation:
The ability of different strains of bacteria to acquire new genes outside of the mechanism of cell division is called horizontal gene transfer (HGT). This mode of gene transfer is distinct from traditional reproduction, where genes are passed down from parent to offspring, which is called vertical gene transfer. HGT is a critical mechanism in the microbial world, enabling bacteria to gain genetic material from other bacteria or the environment, leading to rapid genetic changes and the acquisition of traits such as antibiotic resistance.
There are several methods of horizontal gene transfer, including:
- Conjugation - where genetic material is transferred directly from one bacterial cell to another through a physical connection known as a pilus.
- Transformation - where bacteria take up free DNA fragments from their surroundings.
- Transduction - where genetic material is transferred from one bacterium to another via a bacteriophage, a type of virus that infects bacteria.
Among these mechanisms, conjugation is commonly responsible for the spread of antibiotic resistance genes within a bacterial population. During conjugation, resistance genes often carried on plasmids can be transferred from nonpathogenic bacteria to pathogenic ones, which can lead to significant clinical challenges. Similarly, transformation plays a role when bacteria become competent and take up DNA fragments carrying resistance genes. Transduction via bacteriophages can also move these genes between bacteria.
Microbial genomics studies have highlighted the importance of HGT in disseminating resistance. Transposons, mobile genetic elements, can also be transferred horizontally. These elements can unintentionally introduce resistance genes into a bacterium's genome, further complicating the battle against antibiotic-resistant infections. Understanding these mechanisms is essential for tackling the challenge posed by increasing antibiotic resistance.