Life on a meteorite?

[hitest]

Interesting article!

Extra terrestrial life?

[Pete_C]

Interesting.

I do not think that "life evolved on a meteorite" although some of the organics required could certainly have done so.

It does sound "feasible" that life could have evolved elsewhere before it evolved here on Earth and that a meteorite collision with say Mars could have ejected material which wound up falling on Earth as Meteorites bringing some life with it.

But that leaves us with the question of why Eukaryotes and Prokaryotes. Were one the other or both brought here?

Basically most of the life on Earth is composed of cells with two pools of genetic material. One is the cell nucleus (Nuclear DNA) and the other is the mitochondria (mitochondrial DNA) which provide the cell with energy.

While Nuclear DNA is mingled between parents and rearranged each generation; mitochondrial DNA is passed virtually unchanged from generation to generation.

However there are some very ancient very primitive organisms (Archaea) which have only one gene pool.

Now one theory is that a primitive organism with a nucleus absorbed another smaller organism which did not get digested but instead became a symbiote (the mitochondria) and that this was so much superior that it basically eliminated all its relatives and became the ancestor of most of the life on earth.

The other theory says that they are unrelated, that the Eukaryotes evolved separately from Prokaryotes.

Then we have viruses, unable to replicate themselves they hijack healthy cells to do the job. Where do they fit in? Are they more primitive than the archaea or did they come from more advanced organisms which suffered a random mutation and part of their genetic material went rogue? Some bacteria "swap" portions of genetic code (thus spreading drug resistance for example since they swap with other unrelated bacteria and not just when reproducing) , and this could explain how viruses came into being

Still it is an interesting read.