I hate viruses.... Can viruses infect gametes? If so can this trigger mutations in offspring. Also, how exactly does viruses inject their viral DNA? I have more questions if anyone has the time to answer these.
Viruses were substitute for intermultipication(right word?) in early life. So they kinda helped out evolution and gene diversity a bit.
If a virus infected a gamete then it'd prob die eventually. The idea, or so I am lead to believe, is that the host cells fills up as it produces thousands of viruses and then eventually ruptues from excessive buddings etc. Perhaps someone else can give you a non bullshit answer as to how they inject DNA, but I think (and it's not DNA as we know it, more RNA with some kind of crap attached to it like matrix proteins) that they just shove their stuff in by endocytosis. How the genetic material gets to the nucleas I don't know, but I would imagine by microtubules. Obviously then it gets transcribed and the rough ER begins making new virus bits. There are some terrifying pictuers of a cell getting raped by ebola viruses here
Actually, a virus infecting a gemete seems possible, though not very likely. My only background in bio is taking AP Biology, but I know that viruses can inject their own RNA (dunno about DNA) into the cell which eventually becomes transcribed into the cell's original DNA. I think these viruses are called retroviruses. I'm not entirely sure. It's very rare, but I remember learning that if a virus injects its DNA into a developing human zygote in its early dividing stages (only a few cells), the infected cells will continue to divide all the way up to the maturity and pass along the viral DNA. Essentially, the infected human is a living time bomb. If a specific stimuli sets off the virus, ALL the infected cells in the body that branched off from the one infected cell will die, resulting in a quick and inevitable death. I think someone famous died a year or two ago of a viral infection similar to the one I just described...I want to say it was Mr. Rogers, but I don't think that's the person. Please Register or Log in to view the hidden image!
HIV is a retrovirus, so it is not very rare. And there are DNA and RNA viruses. Not all viruses kill their host cell, some of them just sit there and multiple with host.
Viruses can infect gametes. Proof? The human genome is riddled with LTRs (Long terminal repeats, flanking retroviruses genomes such as HIV-1) coming from viruses who infected primitive humans. They're called HERVs, for Human Endogenous Retroviruses. Interesting stuff, really. And they even got (in some cases) useful functions! A fusogenic peptide expressed from one of these HERV is used by trophoblasts to fuse (forming syncytiotrophoblasts), which is an essential step in placenta formation.
i guess. wont be long before we can probably engineer them. they're relatively simple. not as complex as an organism. :m:
"Ok, well can we use viruses to trigger certain mutations?" Integration of viral DNA into the host genome is a sort of mutation. Any retrovirus can alter gene expression, simply by integrating into a crucial spot in the host genome (e.g., a promoter or exon site). So far it's not possible to direct the site of insertion in humans. It can be done in mice, but requires the experimenter to start with mice that are already genetically modified (with loxP sites flanking the region to be altered, and Cre recombinase expression present in the tissue of interest).
Virus genetic insertion into a genome is usually non-specific and random as to were it inserts. A good percentage of are genome is viral in origin, viruses over the eon have inserted into cells, mutated in such away as to not be able to produce virus any more and thus remained apart of us ever since. Many of these former viruses have become parasitic as transposons, many more simply sit there like dumb shit, few have possible provided beneficial genetic material.
Again, under the system biologists usually use, recombination can be directed to a specific region by flanking that region with loxP sites. But humans aren't usually born with ready-made loxP sites flanking their genes of interest. Please Register or Log in to view the hidden image! Otherwise, transposition is random; or at least, it happens at sites that just happen to have the appropriate sequences.
