Transposons and Mutagenesis in Bacteria

These flashcards cover important vocabulary and concepts related to transposons, mutagenesis, and bacterial genetics as discussed in the lecture.

Hfr strain

A strain of bacteria with a high frequency of recombination due to the presence of an F plasmid integrated into its chromosome.

F' factor

A conjugative plasmid that carries gene(s) from the bacterial chromosome, often resulting from the improper excision of an F plasmid.

Transposon

A DNA sequence that can change its position within the genome, potentially disrupting genes and altering cellular functions.

Composite transposon

A transposon that consists of two insertion sequences flanking a central region containing one or more genes, often conferring antibiotic resistance.

Excision and insertion

The process by which transposons cut themselves from one location in the DNA and insert into another location.

Nonreplicative transposition

A mechanism of transposition where the transposon is cut out from one location and inserted into another without being replicated.

Replicative transposition

A mechanism that results in a copy of the transposon being inserted into a new location while leaving the original intact.

Direct repeats (DRs)

Short sequences of DNA that flank a transposon after it inserts into a target DNA.

Antibiotic resistance genes

Genes that provide bacteria with the ability to survive exposure to antibiotics, often carried by transposons.

Mutagenesis

The process of inducing mutations in an organism's DNA to study the effects of those mutations.

Hfr strain

A strain of bacteria with a high frequency of recombination due to the presence of an F plasmid integrated into its chromosome.

F' factor

A conjugative plasmid that carries gene(s) from the bacterial chromosome, often resulting from the improper excision of an F plasmid.

Transposon

A DNA sequence that can change its position within the genome, potentially disrupting genes and altering cellular functions.

Composite transposon

A transposon that consists of two insertion sequences flanking a central region containing one or more genes, often conferring antibiotic resistance.

Excision and insertion

The process by which transposons cut themselves from one location in the DNA and insert into another location.

Nonreplicative transposition

A mechanism of transposition where the transposon is cut out from one location and inserted into another without being replicated.

Replicative transposition

A mechanism that results in a copy of the transposon being inserted into a new location while leaving the original intact.

Direct repeats (DRs)

Short sequences of DNA that flank a transposon after it inserts into a target DNA.

Antibiotic resistance genes

Genes that provide bacteria with the ability to survive exposure to antibiotics, often carried by transposons.

Mutagenesis

The process of inducing mutations in an organism's DNA to study the effects of those mutations.

F plasmid

A conjugative plasmid in bacteria that carries genes for pilus formation and DNA transfer, enabling genetic exchange between bacterial cells.

Bacterial conjugation

A process of horizontal gene transfer in bacteria where genetic material (e.g., F plasmid) is transferred directly between two bacterial cells through a pilus.

How do transposons cause mutagenesis?

Transposons can disrupt genes by inserting into coding or regulatory regions, leading to gene inactivation or altered gene expression, thereby causing mutations.

Insertion sequence (IS element)

The simplest type of transposon, consisting only of the genes required for transposition (e.g., transposase) flanked by inverted repeats.