Thanks Joachim, I want to imagine atmosphere where Phosphorus has still to be made available for the chemicals to form RNA/DNA

Hello Dr Sisodia!

The traditional answers for alternatives include arsenate, and vanadate (as ions). Glyoxylate has also been suggested (see Bean et al. 2006, Origins of Life and Evolution of Biospheres) and is probably the best organic reagent used as an alternative. If you're curious, check out Westheimer (Science 1987).

A colleague and I have a review chapter on this called "On the Origin of Phosphorylated Biomolecules".

Thank you Dr Pasek!! If origin of elements is taken into consideration and if origin of life can be linked with this origin then a possibility arises that the initial life could be of different elements or may be energy releasing processes (that which is in DNA/RNA) could be different!!!!! Problem is how to prove or disprove this imagination!!!!!

How to prove or disprove this imagination? It is the mother of questions, because we can't prove that on Earth-Life. Why? Well, because we can't yet make Life, and all the Life here in Earth (so far), uses Phosphorus instead of Arsenic. Why the last? Because chemical reactions (and Life for extention), always follow the path of least energy, more stability and more availability. Now, we just can make assessment of the fitness effects of individual mutations on multiple genetic backgrounds.

In my opinion, It appears that the only way how we will be able to understand and to know, other genetic codes or other forms of Life, e.g., Sulfur-Based, Silicon-Based, Ammonia-Based Life, etc., will be until we can detect or collect them. The problem now is how we will going to detect something that we do not know or do not understand, even our own Life is not fully understood. So, there's the risk to fall in the chicken and the egg causality dilemma. This is, What we need first, understand our Life or find other forms of Life?

I believe that the only way to solve this dilemma is to get out of here and Colonize/Terraform other sites, especially those who we judge today as uninhabitable (for humans), even planets Venus-Like or Mars-Like, in order to avoid contaminating on those potentially habitable or even inhabited by some kind of carbon-based life. Any exploration carries a high risk of contamination, however, the interest in finding new sources of energy and resources (and why not, other forms of Life), always involves the improvement or development of better methodologies and technology.

May be.....in the nature's process of natural selection/evolution/improvement, the elements also vie with each other (in life forms) and the more versatile wins. Exoskeleton composed of chitin is not as versatile as endoskeleton composed of calcium phosphate...even calcium carbonate skeletons are inferior to that of calcium phosphate...or imagine silicon with many similar properties as that of carbon but not as versatile as carbon (would silicon instead of carbon in life forms make them transparent...if yes!! think of doctors' convenience with human ailments). Artificial life creators may try with simpler elements first!!!

The attached book is of interest to crack the unanswered question of living and dead vis-a-vis consciousness

Http://golden-ratio-in-dna.blogspot.fr/2010/12/why-arsenic-could-replace-phosphorus.html

more details here: (book CODEX BIOGENESIS) http://fr.scribd.com/doc/220515506/CodexBiogenesisANNEXE1jcPerezCopyright2009-pdf and http://www.amazon.co.uk/Codex-Biogenesis-harmonies-g%C3%A9nome-latome/dp/2874340448 and https://sites.google.com/site/codexbiogenesis/

Thanks Prof Jean....I shall be grateful if you could mail your article (in english) on my

email id: [email protected]

Thanks

OK Dear Mahaceer, here some links in english: and http://www.amazon.co.uk/Codex-Biogenesis-harmonies-g%C3%A9nome-latome/dp/2874340448 and https://sites.google.com/site/codexbiogenesis/ and http://file.scirp.org/Html/4-7401586_37457.htm and http://fr.scribd.com/jean_claude_perez/documents and particularly this Beijing conference http://fr.scribd.com/doc/57828784/jcperezBeijing032011