Well after all the hulllaba about the presence of extraterrestrial DNA in human genome and lots of blogs and articles later inlcuding the ones from mine which talked about the unusual presence and shift in genetic codon makeup in human DNA. More plausible evidence has started to emerge for what can be termed as ET DNA in Human genome, triggered by the completion of the genome sequencing of the marsupial opposum
An international team, led by researchers at the Broad Institute of MIT and Harvard, and supported by the National Institutes of Health (NIH), have announced the publication of the first genome of a marsupial, belonging to a South American species of opossum (Monodelphis domestica ). In a comparison of the marsupial genome to genomes of non-marsupials, including human, published in the journal Nature, the team found that most innovations leading to the human genome sequence lie not in protein-coding genes, but in areas that until recently were referred to as “junk” DNA. Genome of the marsupial Monodelphis domestica reveals innovation in non-coding sequences the study helps to explain the evolutionary origins of human DNA and the role played by transposons,
The study reveals a surprising role in human evolution for “jumping genes”—
So how does the marsupial genome sequencing explains what has been refered as the presence of extraterrestrial gene or well of course we dont have any ET DNA
In the words of Broad Institute director Eric Lander “Evolution is tinkering much more with the controls than it is with the genes themselves,”. “Almost all of the new innovation … is in the regulatory controls. In fact, marsupial mammals and placental mammals have largely the same set of protein-coding genes. But by contrast, 20 percent of the regulatory instructions in the human genome were invented after we parted ways with the marsupial.”
It showed that an important source of genetic innovation comes from bits of DNA, called transposons, that make up roughly half of our genome and that were previously thought to be genetic “junk.”
The research shows that this so-called junk DNA is anything but, and that it instead can help drive evolution by moving between chromosomes, turning genes on and off in new ways.
“The official textbook picture of how genes work really didn’t appear to be right,” Lander said. “There was much more of the genome standing around shouting instructions than actually producing proteins.”
That raised a question of how evolution actually works on the genome, Lander said. With so much of the genome devoted to regulation, it became apparent that evolution could work by simply changing the instructions rather than changing the protein-coding genes themselves.
Now that perhaps explain all the articles you may have come across about the discovery of extraterrestrial genes in human DNA
Thus, the mobile elements that are typically thought of as “junk DNA” have played a creative role in genome evolution – spreading key genetic innovations involved in the control of gene expression across the genome.
A tiny opossum’s genome has shed light on how evolution creates new creatures from old, showing that change primarily comes by finding new ways of turning existing genes on and off