Tag: science

DNA precursors in space

Consider this: we have the capability to detect the presence of very specific molecules from 25k light years away. This is just mind-boggling.

Researchers have discovered prebiotic (pre-life) molecules in interstellar space that may have formed on dusty ice grains floating between the stars. The molecules were detected near the center of our Milky Way Galaxy — specifically, the star-forming region Sagittarius(Sgr) B2(N), which is the richest interstellar chemical environment currently known. 1 of the newly-discovered molecules, called E-cyanomethanimine (E-HNCHCN) is one step in the process that chemists believe produces adenine, 1 of the 4 nucleobases of DNA. The other molecule, called ethanamine, is thought to play a role in forming alanine, 1 of the 20 amino acids in the genetic code.

2014-10-03: Isopropyl cyanide, needed for life

Astronomers have detected radio waves within a giant gas cloud in interstellar space corresponding to an unusual carbon-based molecule called isopropyl cyanide, needed for life. Organic molecules usually found in these star-forming regions consist of a single “backbone” of carbon atoms arranged in a straight chain. But the carbon structure of isopropyl cyanide branches off, making this the first interstellar detection of such a molecule


2014-12-02: DNA itself can also survive in space. This makes Panspermia (and contamination of the seas of europa by humanity’s probes) more likely.

Surviving space flight, 1000°C temperatures, re-entry into Earth’s atmosphere, and landing, 35% of the DNA retained its full biological function

2022-03-13: Peptides can form on cosmic dust

Without any of the enzymes that biochemistry provides, the production of peptides is an inefficient 2-step process that involves first making amino acids and then removing water as the amino acids link up into chains in a process called polymerization. Both steps have a high energy barrier, so they occur only if large amounts of energy are available to help kick-start the reaction.

Because of these requirements, most theories about the origin of proteins have either centered on scenarios in extreme environments, such as near hydrothermal vents on the ocean floor, or assumed the presence of molecules like RNA with catalytic properties that could lower the energy barrier enough to push the reactions forward. And even under those circumstances, “special conditions” would be needed to concentrate the amino acids enough for polymerization. Though there have been many proposals, it isn’t clear how and where those conditions could have arisen on the primordial Earth.

But now a group of astrobiologists showed that peptides, the molecular subunits of proteins, can spontaneously form on the solid, frozen particles of cosmic dust drifting through the universe. Those peptides could in theory have traveled inside comets and meteorites to the young Earth — and to other worlds — to become some of the starting materials for life.

Revive

Paging Michael Crichton. Oh wait, he’s dead himself.

Why do it? Why revive extinct species?
For the same reasons we protect endangered species. To preserve biodiversity and genetic diversity. To undo harm that humans have caused in the past. To restore diminished ecosystems. To advance the science of preventing extinctions.

Ethics arbitrage

In China, a research project aims to find the roots of intelligence in our DNA; searching for the supersmart

it would appear that the biggest sequencing lab in the world has no qualms about research that would not pass ethics approval in the west. of course, the results of that research will not be ignored by the west, how convenient.

Cosmos

if you haven’t seen this yet (unlikely, i know), it is free on hulu. it has held up remarkably well in the over 30 years since it was made. it would be amazing if it were updated in the same style. we’d have to cast a new carl sagan.
2013-07-21: the cosmos remake is coming out next year. i hope tyson has as much of a facility with words as sagan did.

2014-01-13: the first episode is on march 9. the original with carl sagan was seen by 750M people, let’s hope this one goes to a couple billion.

2014-03-11: Let’s hope this is the beginning of fighting back against the forces of ignorance. You are watching this, right?

Predicting Deception

a text analysis program correctly classified liars and truth-tellers at a rate of 67% when the topic was constant and a rate of 61% overall. Compared to truth-tellers, liars showed lower cognitive complexity, used fewer self-references and other-references, and used more negative emotion words.

61% is not very useful (close to a coin toss), but it is an interesting start. of course, this research suffers from the usual problems (only 5 samples, wtf?), but given a few 100K samples, might be much more accurate.

Word prevalences

“amicorum meorum vivorum et mortuorum”, which means “of my friends living and dead”, was popular between the years 1150 and 1240 but not at other times. And the phrase “Francis et Anglicis”, which is a form of address meaning “to French and English”, was phased out when England lost Normandy to the French in 1204.

by using the word distribution of documents with known dates as standard tree rings.