Second genesis

{{Sources needed}}{{evolution}}
'''Second genesis''' is a very general and loose term that means a case of [[abiogenesis]] that didn't result in us, that is, life based around the molecule of [[DNA]]. It can refer to [[extraterrestrial]] life that has evolved on other [[planet]]s, but in more specific cases it refers to life being produced on [[Earth]] in an independent event. It is also important to note that "second" may not necessarily be second chronologically; it is entirely possible that the life we see on the planet now originated from the second or third (etc.) forms of life.

==Importance==
The importance of discovering a second, independent abiogenesis is huge as it affects the probability of life spontaneously arising on other planets in the galaxy and [[Universe]]. If a second form of life (sometimes termed "shadow life") is found on Earth, it means that the odds of life appearing elsewhere in the Universe can be estimated to be much higher. Such a project to search for life on Earth would be minuscule in cost compared to exploring space but would still give [[SETI]] a much needed confidence boost.

Not to mention the fact that such a discovery would be a very firm kick in the balls to [[creationism]], which likes to protest that abiogenesis is extremely unlikely. Having it happen ''twice'' would be interesting &mdash; but of course, there is no evidence yet that it has happened.

==Artificial life==
There have been studies to produce DNA-like molecules artificially in the lab. These self-replicating molecules have been shown to undergo some form of evolution, but it is unlikely that they will produce anything complex in time for their lab coat wearing creators to see it. If life is defined as something that can undergo evolution through natural selection (transferring and conserving information from one generation to another), then these may well be the first artificial life produced and essentially a confirmed second genesis on the planet Earth.

It is important to note that despite the artificial nature of these molecules and the "intelligence" of the scientists making them, they were still produced through natural, and not [[supernatural]], means.

==A "true" second genesis==
Determining a true second genesis is difficult. Indeed, because abiogenesis is a ''process'' rather than a single event, it's possible that it's happening all the time but never gets far along enough to be noted. As is noted with the [[Peanut Butter Argument]], a second form of life would be quite weak compared to the established first form, and would be very likely to get thoroughly outcompeted by us what with our several-billion-year head start.  Defining what constitutes a "second" genesis also causes problems as the principles of [[natural selection]] show that isolation can very rapidly create new and very different species. If natural selection can occur at the chemical level &mdash; which is likely &mdash; it may well be that these hypothetical "second genesis" life forms do, in fact, share a [[common descent|common ancestor]] with DNA-based life, but this ancestor will be very old, predating the formation of [[cells]] and possibly the use of [[proteins]].

The confusion of what would be a "true" second genesis was shown in December 2010 when leaks of a [[NASA]] press conference suggested a second genesis of [[arsenic]]-utilising [[bacteria]].<ref>[http://gizmodo.com/5704158/nasa-finds-new-life Gizmodo - NASA finds new life]</ref> The actual release was impressive, but not quite a "second genesis", and more of a very extreme adaptation where [[GFAJ-1|bacteria could replace the phosphorus in its DNA with arsenic]],<ref>[http://www.bbc.co.uk/news/science-environment-11886943 BBC News &mdash; Arsenic-loving bacteria may help in hunt for alien life]</ref> and even that turned out to be false.<ref>[https://slate.com/technology/2012/01/independent-researchers-find-no-evidence-for-arsenic-life-in-mono-lake.html Independent researchers find no evidence for arsenic life in Mono Lake] by Phil Plait (Jan 23, 20122:04 PM) ''Slate''.</ref>

This is also an issue for the search for extraterrestrial life, as there is a remote possibility that life that has evolved on other planets may share some kind of ancestry with life on Earth. This hypothesis is generally termed [[panspermia]].

==See also==
*[[Abiogenesis]]
*[[Evolution]]
*[[Peanut butter argument]]

==External links==
*[http://www.telegraph.co.uk/science/science-news/4974917/Artificial-life-could-be-created-within-five-years.html Artificial life 'could be created within five years'] This was published in 2009, will we get new life by 
2014
 
2015
 
2016
 {{CURRENTYEAR}}? Oops &mdash; not bloody likely!

==References==
{{reflist}}

[[Category:Biology]][[Category:Chemistry]][[Category:Science]]

Categories: Biology, Chemistry, Science