12 JAN 2018 by ideonexus
Neurons Use Viruses to Share Information and Learn
When genes are activated, the instructions encoded within their DNA are first transcribed into a related molecule called RNA. Shepherd’s colleague Elissa Pastuzyn showed that the Arc shells can enclose RNA and move it from one neuron to another. And that’s basically what retroviruses do—they use protein shells to protect their own RNA as it moves between cells in a host.
So our neurons use a repurposed viral gene to transmit genetic information between each other in an oddly virus-like... 1 
notes
notes31 MAY 2015 by ideonexus
Genetic Language is Abstract and Flexible
The awesome power that genetic engineering will
one day place in our hands was foreshadowed recently
by some experimenters at the University of Basel in
Switzerland. Walter Gehring and his students were
studying the effects of the eyeless gene in fruit flies. The
gene is called eyeless because its absence causes flies to
grow without eyes. The gene actually causes eyes to grow. Gehring and the students inserted the gene into
various tissues of embryonic flies, and the embryos
grew into flies ... 1 notes
notes30 JAN 2015 by ideonexus
The DNA Prism
The standard DNA 'prism' is a gel electrophoresis column, that is, a
long tube filled with jelly through which an electric current is passed. A
solution containing the scissored stretches of DNA, all jumbled together,
is poured into one end of the tube. The DNA fragments are all electrically
attracted to the negative end of the column, which is at the other end of
the tube, and they move steadily through the jelly. But they don't all
move at the same rate. Like light of low vibration frequenc... 1 notes
notes24 DEC 2013 by ideonexus
An Early Experiment Hinting at DNA
Anomaly (2) was observed by Fred Griffith, decades before DNA and the genetic code. He found that if you inject a heat-treated, dead, virulent species of bacteria (pneumococcus S) into a rat previously infected with a nonvirulent species (pneumococcus R), then species R became transformed into species S, thereby killing the rat. About fifteen years later, Oswald Avery found that you can even do this in a test tube; dead S would transform live R into live S if the two were simply incubated tog... 1 notes
notesV. S. Ramachandran on a fascinating experiment involving combining dead bacteria with live to produce new bacteria.
16 JUL 2013 by ideonexus
DNA Divergence is in How You Count
It’s a common misconception that chimp DNA
differs from Homo sapiens sapiens genes by only a
single percent, but this number is apocryphal. In actuality,
the degree of similarity of human and chimp
genetic code depends mostly on how you count.
Since all complex organisms from Earth possess
great swaths of junk DNA inherited from a distant
common ancestor, there tends to be startling similarity
between many organisms. Sure, humans are like
chimps—but they’re also like flatworms and fruit...Folksonomies: dna genetic drift
Folksonomies: dna genetic drift
1 There's much more to the differences between Chimps and Humans than counting genes.
08 JUN 2012 by ideonexus
One Half of DNA is Parasitic
Parasites are not only incredibly diverse; they are also incredibly successful. There are parasitic stretches of DNA in your own genes, some of which are called retrotransposons. Many of the parasitic stretches were originally viruses that entered our DNA. Most of them don't do us any harm. They just copy and insert themselves in other parts of our DNA, basically replicating themselves. Sometimes they hop into other species and replicate themselves in a new host. According to one estimate, ro... 1 notes
notesThis doesn't sound right to me, but the claim is that Viruses have inserted so much DNA into our genomes.
23 APR 2012 by ideonexus
The Lifetime of DNA
The messages that DNA molecules contain are all but eternal when seen against the time scale of individual lifetimes. The lifetimes of DNA messages (give or take a few mutations) are measured in units ranging from millions of years to hundreds of millions of years; or, in other words, ranging from 10,000 individual lifetimes to a trillion individual lifetimes. Each individual organism should be seen as a temporary vehicle, in which DNA messages spend a tiny fraction of their geological lifeti... 1 notes
notesIt exists in living messengers for brief periods of their lifetimes, but communicates across millions of years throughout all life.
23 APR 2012 by ideonexus
It's Raining DNA Outside
It is raining DNA outside. On the bank of the Oxford canal at the bottom of my garden is a large willow tree, and it is pumping downy seeds into the air. ... [spreading] DNA whose coded characters spell out specific instructions for building willow trees that will shed a new generation of downy seeds. … It is raining instructions out there; it's raining programs; it's raining tree-growing, fluff-spreading, algorithms. That is not a metaphor, it is the plain truth. It couldn't be any plainer...There is DNA everywhere, in seeds in bacterium, it's all around us, this programming for life.
23 MAR 2012 by ideonexus
Nucleic Acids Unify Biology
We are now witnessing, after the slow fermentation of fifty years, a concentration of technical power aimed at the essential determinants of heredity, development and disease. This concentration is made possible by the common function of nucleic acids as the molecular midwife of all reproductive particles. Indeed it is the nucleic acids which, in spite of their chemical obscurity, are giving to biology a unity which has so far been lacking, a chemical unity. 1 notes
notesBy providing a molecular starting point for everything else.
17 MAR 2012 by ideonexus
The Sequence Hypothesis and The Central Dogma
My own thinking (and that of many of my colleagues) is based on two general principles, which I shall call the Sequence Hypothesis and the Central Dogma. The direct evidence for both of them is negligible, but I have found them to be of great help in getting to grips with these very complex problems. I present them here in the hope that others can make similar use of them. Their speculative nature is emphasized by their names. It is an instructive exercise to attempt to build a useful theory ... 1 notes
notesCrick describes two guiding principles of understanding how DNA produces proteins. The second is interesting for the use of the term 'information.'
