Month: September 2022

GETTING SETTLED. "Add the exons — exons are the sequences that specify the code for making the proteins that carry out our bodily functions — and that pushes the percentage of “functional” sequences up to 9 percent, which is pretty close to 8.2 percent. (Yes, it is an astonishing fact that protein-coding sequences, which are what we mostly mean when we say “genes,” occupy only a little over 1% of the human genome.)" https://www.geneticliteracyproject.org/2014/08/05/how-much-of-human-dna-is-doing-something/ View in LinkedIn

BIG SURPRISE. "The 8% is nearly all regulatory sequences, DNA that governs the behavior of the 1 percent of DNA that codes for proteins...until the ENCODE project, scientists thought regulatory sequences would take up about the same amount of space as protein-coding sequences. It was a big surprise to learn that the DNA that regulates genes was eight times bigger." https://www.geneticliteracyproject.org/2014/08/05/how-much-of-human-dna-is-doing-something/ View in LinkedIn

NEUTRAL DNA. "The rest of the genome, Birney said in 2012, is not–as some would have it — just biological “noise.” He prefers to call that DNA “biologically neutral,” meaning “that there are totally reproducible, cell-type-specific biochemical events that natural selection does not care about." https://www.geneticliteracyproject.org/2014/08/05/how-much-of-human-dna-is-doing-something/ View in LinkedIn

RESIDUAL DNA. "So what’s the other 90 percent of the human genome up to? It has been called junk, and although scientists don’t much like that term, junk is what a lot of it appears to be. Some of that DNA, for instance, is leftover fragments of dead viruses that invaded our ancestors’ genomes aeons ago." https://www.geneticliteracyproject.org/2014/08/05/how-much-of-human-dna-is-doing-something/ View in LinkedIn

MOLECULAR PARASITES. "But most of the 90 percent consists of DNA sequences called transposons. Occupying fully half the human genome, transposons are stretches of DNA that can hop around in host DNA. They are somewhat related to viruses, and Sean Eddy...calls them “molecular parasites.” https://www.geneticliteracyproject.org/2014/08/05/how-much-of-human-dna-is-doing-something/ View in LinkedIn

FAST BREEDING. "We do delete them, but they replicate so fast that we can’t keep up. Transposons, however, are not essential for a successful life. A little weed called the humped bladderwort. Only 2.5 percent of its genome is transposons, compared to 50 percent transposons in Homo sap." https://www.geneticliteracyproject.org/2014/08/05/how-much-of-human-dna-is-doing-something/ View in LinkedIn

DRIVING EVOLUTION. "Transposons are also the raw material of evolution. When these mobile elements move around in eggs and sperm, they can increase genetic diversity....transposons have contributed to human success by speeding our unusually rapid evolution, especially evolution of our big brains." https://www.geneticliteracyproject.org/2014/08/05/how-much-of-human-dna-is-doing-something/ View in LinkedIn

STORM IN A TEACUP. The apparent flip-flop over functional DNA appears lodged in definitional disagreements. "How could the meaning of one word—function—be so divisive?" https://lnkd.in/eqwEMmU View in LinkedIn

"BACTERIOPHAGES – or phages for short – are viruses that attack bacteria but not humans. They have only one objective: their reproduction. Phages are so poorly equipped, however, that they can’t do this on their own. Without the help of their victims, they aren’t much more than a dead piece of protein with a touch of genetic material. But if the phages do hit a suitable bacterium, they multiply in a chillingly efficient cycle." https://lnkd.in/eZQvpdQ View in LinkedIn

PHAGES. "Like all viruses, phages are metabolically inert in their extracellular form (the “virion”), and they reproduce by insinuating themselves into the metabolism of the host. The mechanisms by which phage virions infect their host cells...vary among the different types of phages, but they all result in delivery of the phage genome into the cytoplasm of the bacterial host, where it interacts with the cellular machinery to carry the phage life cycle forward." https://lnkd.in/eBxpUF7 View in LinkedIn