genetics question.. please help!!

[ilovefood]

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how does foreign DNA integrate itself into a genome?

does it just insert itself inside the host DNA, or does it do this by homologous recombination?

does recombination just happen on its own???

 

[EBI831]

it needs some kind of vector(a plasmid etc). if it just jumped in there'd be too little of a chance that it would hit the exact right gene it wanted. i also think that it recombines with host DNA if it wants to be incorporated into DNA and cause damage/replicate, etc.

 

[superwillis]

I'm pretty sure some enzymes (polymerases) are involved. The foreign DNA doesn't have the ability to "insert" itself I don't think. Usually something needs to cut the vector/plasmid at a certain location before the DNA can be incorporated.

 

[NontradICUdoc]

This is the lytic vs lysogenic cylce that you are talking about. When a virus attacks a cell, it can either inject its DNA into the cell, like a bacteriophage, or it enters the cell and opens its protein coat exposing the genetic material.

If the virus is a retro-virus, it needs reverse transcriptase in order to tansform the RNA into DNA and then insert itself into the host's DNA. If it is a DNA virus, it enters the lysogenic cycle and simply integrates itself into the host's genome until such time that it will enter the lytic phase. In a bacteria, the DNA is a prophage that is a circular piece of DNA and it replicates the host's DNA.

 

[TMP-SMX]

how does foreign DNA integrate itself into a genome?

does it just insert itself inside the host DNA, or does it do this by homologous recombination?

does recombination just happen on its own???

I think you are confused with two totally separate issues.

Recombination occurs during prophase of meiosis.

Foreign DNA is taken into a cell through transformation or by many other means of transport depending on the cell and the vector.

 

[Condeeleza Rice]

My teacher went over this in class, for a linear piece of DNA from the bacteriophage to incorporate into the host DNA, there must be a double crossover for it to get the whole piece. For a circular piece of DNA to be incorporated, only a single crossover needs to occur. That is why it is advantageous for viral DNA to be circular. In addition to being circular, restriction enzymes cannot find ends to chew up because it is circular, so it will not recognize the virus DNA as foreign DNA. This teacher was a grandmaster teacher of TPR or something(top 5 bio/orgo teachers in the nation) until examkrackers took him from them.

 

[TMP-SMX]

My teacher went over this in class, for a linear piece of DNA from the bacteriophage to incorporate into the host DNA, there must be a double crossover for it to get the whole piece. For a circular piece of DNA to be incorporated, only a single crossover needs to occur. That is why it is advantageous for viral DNA to be circular. In addition to being circular, restriction enzymes cannot find ends to chew up because it is circular, so it will not recognize the virus DNA as foreign DNA. This teacher was a grandmaster teacher of TPR or something(top 5 bio/orgo teachers in the nation) until examkrackers took him from them.

If it's not in your intro bio book it's not going to be on the MCAT... And yes. Viruses have evolved as cells have. They find ways from having their DNA/RNA destroyed by host cells.

 

[ilovefood]

i want to know what it means by "integrate"... like HOW does it integrate.. via recombination? it cant just jump in.

when you say cut and insert.. i think that is what they do in research(not my question). use restriction enzymes for plasmids and DNA, have sticky ends attach.

 

[TMP-SMX]

i want to know what it means by "integrate"... like HOW does it integrate.. via recombination? it cant just jump in.

when you say cut and insert.. i think that is what they do in research(not my question). use restriction enzymes for plasmids and DNA, have sticky ends attach.

The viral enzyme integrase...