I tried searching on google, but I couldn’t find anything. So how 'bout it, dopers? What makes a retrovirus different?
Almost all life on Earth reproduces by transcribing DNA into RNA; regular viruses contain DNA, and use their host’s own mechanisms to do the trick.
Retroviruses contain RNA, and use reverse transcribase to trnascribe their RNA into DNA, which the host’s mechanisms then use to make more viruses.
OK, thanks.
retrovirus
n : any of a group of viruses that contain two single-strand linear RNA molecules per virion and reverse transcriptase (RNA to DNA)
The more common DNA viruses don’t need a reverse transcriptase, since they carry their genetic information in the standard, DNA, format. More here.
Since somebody has already given a clear accurate answer, let me just add that retroviruses can be easily recognized by their 1970’s outfits and hairdos. 
One might also point out that retrovirii leave their genetic material (or rather, a DNA copy of it) permanently implanted in the host’s cells. This makes them particularly difficult to fight, but it also makes them highly useful to genetic engineers who wish to alter the DNA of an existing cell or organism.
True, but that’s not unique to retrovirii. Others do that as well.
Really? I was under the impression that normal viruses could insert themselves into bacterial DNA, but in eukaryotes they were blocked by the nucleus membrane and so could only make copies of themselves but not inject proviruses into our chromosomes. Is this wrong? I thought that the whole “point” of retroviruses was to get around the nucleus barrier and make permanent modifications to our chromosomes.
Herpesviruses are examples of DNA viruses that integrate into the genome. HSV 1 and 2, varicella zoster, HHV8 - they all do it. So does human papilloma virus, but I can’t remember offhand if that’s a herpes virus or not. Anyway, the majority of cancer-causing viruses integrate.
As far as engineering goes, I vaguely remember hearing of work being done with DNA viruses. I can’t say for sure that retroviruses are used more often, or, if they are, why. I could make up some plausible-sounding reasons, but I don’t know.
Viruses can also transfer genes from other organisms into YOU. More importantly, they can move antibiotic resistance genes from one bacterium to another. This is one of the reasons I am not concerned with GM foods, since there is nothing in them that cannot happen naturally and has happened all through evolution on earth. Except it is controlled.
I thought they drove big cars with tail fins and wore bowling shirts and tight pants.
What is all this? Why isn’t a virus a virus? Do rotovirusus (virii?) gyrate? - Jinx
Here is probably more than you want to know on origins on types of virii:
http://www.uct.ac.za/microbiology/tutorial/virorig.html
Be prepared for words such as papillomaviruses and Rhabdoviridae
Rhabdo = bullet-shaped!
Out of everything I learned in my Viro class, that one bit of trivia is stuck on the top of the heap, popping up uncontrollably at inconvenient times.