One Species' Genome Discovered Inside Another's 224
slyyy writes "The Universtiy of Rochester has discovered the complete genome of a bacterial parasite inside the genome of the host species. This opens the possibility of exchanging DNA between unrelated species and changing our understanding of the evolutionary process. From the article: 'Before this study, geneticists knew of examples where genes from a parasite had crossed into the host, but such an event was considered a rare anomaly except in very simple organisms. Bacterial DNA is very conspicuous in its structure, so if scientists sequencing a nematode genome, for example, come across bacterial DNA, they would likely discard it, reasonably assuming that it was merely contamination--perhaps a bit of bacteria in the gut of the animal, or on its skin. But those genes may not be contamination. They may very well be in the host's own genome. This is exactly what happened with the original sequencing of the genome of the anannassae fruitfly--the huge Wolbachia insert was discarded from the final assembly, despite the fact that it is part of the fly's genome.'"
mmm... home made mutants! (Score:3, Informative)
Re:scifi tag? (Score:5, Informative)
mitochondria, chloroplasts, viral DNA (Score:5, Informative)
phoenix (Score:5, Informative)
Re:scifi tag? (Score:4, Informative)
Re:scifi tag? (Score:4, Informative)
Re:scifi tag? (Score:3, Informative)
In fact _most_ of the genes that encode mitochondrial proteins are now in the nucleus, presumably a result of ancient DNA transfer from the primordial mitochondrial genome to the nuclear genome, so the parent post is substantially correct. The modern mitochondrial genome is pretty vestigial (smaller than that of many viruses). The original article speculates that a Wolbachia bug might one day evolve into an organelle by similar processes, and suggests that the existing insert may have a selective advantage for the host.
Re:scifi tag? (Score:4, Informative)
Re:scifi tag? (Score:5, Informative)
Evolutionary Tree not a Tree (Score:3, Informative)
Re:mitochondria, chloroplasts, viral DNA (Score:3, Informative)
Re:Mebbe it's just me but (Score:4, Informative)
Uh huh, and how exactly do you propose to do that? (also, doing this on a human seems like a pretty bold move)
People tend to throw around "junk DNA" without really specifying what they mean. For humans, we know that about 1.5% is coding, about 4% is highly conserved (so, probably very important) and we suspect that a fair amount more is involved in transcription regulation (there's been a lot of activity in that particular area recently), but we have a very faint idea of how much that would be. I saw a talk a few weeks ago where they claimed that nearly all non-coding DNA is involved in this function; that's not a widely held view, though.
It seems likely that since there are so few actual genes and they are so sensitive to mutation, then a highly redundant and more "flexible" mechanism for transcription regulation is one of the primary mechanisms for evolution.
So yeah, I am not sure where the popular perception that non-coding DNA is considered to do nothing comes from.
Oh, and as someone already pointed out, the number of chromosomes a particular organism has is completely meaningless (chickens have 78, some primitive plants have hundreds or even thousands).
Actually, it's very easy to imagine (Score:3, Informative)
Actually, it's very easy to imagine. Transcribing DNA to proteins happens between a START and a STOP marker. If those markers are lost -- heck, even if just the START marker is lost -- then that piece of code is never "executed". In programming terms, it's commented out.
And, yeah, your genetic code contains a whole bunch of commented-out sequences. Dunno, I don't have much trouble believing that they have no impact whatsoever
Re:scifi tag? (Score:2, Informative)
Re:scifi tag? (Score:4, Informative)
http://en.wikipedia.org/wiki/Mitochondrion#Replic
http://en.wikipedia.org/wiki/Mitochondrial_DNA#Mi
I don't know what kind of access you have to scientific journals but this abstract has a pretty good description of sperm mitochondria and how they are degraded via ubiquitinylation (a common degradation pathway)
http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubme
Hope that helps.