I Believe Life did not Originate on Earth
چرا معتقدم حیات در کره زمین بوجود نیامده است
Acknowledgement: I need to note that especially in the area of biology and genetics I owe a lot to a young scientist who has asked me not to mention his name, otherwise, rightfully this writing just like my book about New Variant (1) should have borne the name of two authors.
Earth was formed about 4.5 billion years ago (2). More weight is now given to hypothermal vents in the deep sea rather than surface of the planet, as location of first life-forms on Earth (3). Archaebacteria are the oldest life-forms on Earth and current research traces them to about 4.1 billion years ago (4).
RNA is believed to be older than DNA. RNA and DNA are chains of nucleotides. DNA is composed of one of four nitrogen-containing nucleobases—either Cytosine, Guanine, Adenine, or Thymine. In other words, all DNA on Earth is made of CGAT sequences (5). RNA's composition is the same except that instead of Thymine, it has Uracil, thus it is made of CGAU sequences (6).
We can see various paths in the inanimate geological development of Earth and also various branches in the taxonomy of biological evolution on Earth but when it comes to RNA/DNA, everything is just CGAU/CGAT based! In other words, if life had originally evolved on Earth, we should have traced remnants of life-forms based on other kinds of nucleobases, even if they did not all survive, the same way multitudes of geological forms have developed on Earth and various species have evolved on Earth since the inception of RNA/DNA on Earth.
It seems that life has evolved elsewhere in the universe, and in that location, life forms with other nucleobases may have evolved but only CGAU/CGAT left its birthplace arriving on Earth about 4 billion years ago. If this hypothesis is true, perhaps the RNA/DNA based on CGAU/CGAT have spread to other stars, planets and moons as well, and might have survived and evolved in some other locations in the universe where the cousins of our biological entities could exist to this day.
Hoping for a democratic and secular futurist republic in Iran,
Sam Ghandchi, Editor/Publisher
December 28, 2016
1. New Variant to Meet Human Needs-An Electronic
واریانت جدید برای تأمین نیازهای بشر- کتاب الکترونیک
2. Age of the Earth
3. We’ve been wrong about the origins of life for 90 years
4. Life on Earth likely started 4.1 billion years ago—much earlier than scientists thought