Do you remember being very dubious of all those aliens and humans mating and having children on Star Trek? Now wait a minute, didn’t you say? How could beings from totally different planets with different histories of genetic descent possibly do that?

Some researchers are hinting at an answer. Seems that 10 of our 20 amino acids are very likely to form in the cosmos. Hmmmmm. Maybe Klingon-Human hybrids are possible after all. Check out the hot action here.

We know that amino acids are common in our solar system and beyond. Various first experiments to recreate the conditions in the Earth’s early atmosphere have produced 10 of the amino acids found in proteins. Curiously, analyses of meteorite samples have found exactly these same 10 amino acids. Various researchers have noted this link but none have explained it.

Now we know why, say Higgs and Pudritz. They have ranked the amino acids found in proteins according to the thermodynamic likelihood of them forming. This turns out to match the observed abundances in meteorites and in early Earth simulations, more or less exactly.

That’s a neat piece of work. They go on to argue that the first genetic codes must have evolved to exploit these 10 prebiotic amino acids. The other amino acids which are all bigger and generally more difficult to synthesise must have been incorporated later. At any rate, Nature had settled on the full 20 we see today by the time the earliest common ancestor of all organisms on the planet first emerged, at least 3.5 billion years ago.