How does bacteria acquire new genes?

Question

"If a bacteria acquired an antibiotic-resistant gene from its environment, would that be considered to involve new genetic make up? Please dumb down your answers to make them easy to understand. Thank you."

Answer 1

Transduction: Movement of DNA from one bacteria to another by a virus.

Conjugation: Kinda of like s*x for bacteria. DNA on a specilized plasmid (a circular piece of DNA not part of the chromosome) moves from a donor bacteria to a recipient bacteria.

Transformation: Bacterial cells picking up naked DNA from their environment.

All three mechanisims can allow a bacteria to pick up genes from it's environment.

Answer 2

The most common mechanism for a bacterium acquiring a new gene is conjugation and plasmid exchange.

Plasmids are short loops of DNA which are not part of the normal bacterial chromosome. They often contain useful but nonessential genes - like antibiotic resistance, and bacteria are capable of exchanging plasmids, and thereby giving resistance genes to each other.

Other mechanisms of gene acquisition would be:

- viral transfection, where a virus containing a particular gene infects the bacterium, and gives the gene to it. The virus would normally kill the bacterium, however.

- mutation, where a gene controlling the process that is targeted by the antibiotic mutates in such a way as to make the bactrium resistant.

- gene duplication, where a mistake in DNA replication accidentally copying a gene twice. This allows each version of the gene to mutate seperately - eventually possibly resulting in two totally different genes with different effects (one of which might be antibiotic resistance).

Of these, only mutation is likely to convey a antibiotic resistance in the short-term.

All four mechanisms DO involve a "new genetic makeup".

Answer 3

I beleive that what makes the bacteria antibiotic-resistant is the Plasmid, (extra chromasomal circle of Dna not essential to cell), called R-factor Plasmids.  This being true, I think that this would not be considered to involve new genetic make-up of the original chromosome.

Answer 4

Transduction is the process by which DNA is transferred from one bacterium to another by a virus.

Bacterial conjugation is the transfer of genetic material between bacteria through direct cell-to-cell contact.

Answer 5

No it doesn't pick up a gene out of nowhere.  Mutations cause the new genes.  Mutations like frame shift mutations, point mutations, and some i can't think of right now.

Edit:  Just read up on this and learned something new.  What i said is right.  I never knew that bacteria can convey their resistance to antibiotics through plasmids.  An extra chromosomal section of DNA capable of replicating independently from chromosomal DNA.