Human chromosomes have a very vast amount of microbial DNA incorporated in them, I was wondering how it made its way here? Lateral gene transfer? Our evolution occurred from a unicellular stage to multicellular human specie? or we were created from a mixture of soil, water with microbes already present in it?. Junk DNA does not appears that much junk, I guess.
Hi,
About 30% of healthy Human genome consists of bacterial DNA (much more in cancer cells) and approximately eight percent of human genetic material comes from viruses and not from our ancestors.
New research show that gene transfer from bacteria to humans is not only possible, but also somehow linked to over-proliferation: either cancer cells are prone to these intrusions or the incoming bacterial genes help to kick-start the transformation from healthy cells into cancerous ones.
The vast number of bacteria in our bodies regularly exchange DNA with each other, but the idea that their genes could end up in human DNA has been very controversial. In 2001, the team that sequenced the first human genome claimed to have found 113 cases of such lateral gene transfers (LGT), but their conclusion was later refuted.
See this website:
http://www.the-scientist.com/?articles.view/articleNo/36108/title/Bacterial-DNA-in-Human-Genomes/
This high-profile error “had a chilling effect on the field,” according to Julie Dunning Hotopp who led the new study. Although her team has since found several cases of LGT between bacteria and invertebrates, “it’s still difficult to convince people that it may be happening in the human genome,” she said.
Dear
Your question is interesting but complicate to be answered. May be technology of CRISPR/cas9 could give some opportunities.
Thank
Marius
If you consider viruses are microbes (that statement itself remains a major point of contention in taxonomic classification and definition), the reason why humans have so much microbial DNA of viral origin might have arisen due to an ancestral viral infection of the eukaryotic ancestor, which resulted in the integration of retroviral-like sequences in the human genome.
My curosity is, could the humans have incorporated these DNA sequence at a begning point and continued it during evolution? We dont know how we had such a big jump to become encephalized, as evolutionary expert say that even doing so from chimps and monkeys would take aprox 3.8 billion years at its rapid speed. My brain says we were crafted from a material that had these DNA sequences from the formation point....We have to explore more open mindedly, I guess.
Mannan
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