In 1969, near the town of Murchison, Australia, a bright fireball slammed into the earth and created a tremor felt for miles around. Leaving a cloud of smoke, it was soon discovered that the object was a meteorite - spewing fragments in a thirteen mile radius. Upon impact, the space rock remained intact, but several small fragments broke off, with a peice that actually broke through a roof and landed on a pile of hay. This strange and distant flight through space, ended on Earth and then part of it, lay there smoldering on a haystack - like an opening scene in a movie that couldn't have been better directed. Known as the Murchison meteorite it is one of the most studied meteorites due to it mass— but thats not all...it belongs to a group of meteorites rich in organic compounds. So this is only the beginning of the story.
The meteorite belonged to something called a CM group (carbonaceous chondrites) which meant it experienced extensive alterations by water-rich fluids on its parent body before falling to Earth. Like other CM chondrites Murchison contained the basic components of life building chemicals known as amino acids. When first studied, we found it had amino acids such as glycine, alanine and glutamic acid, diamond acids as well as unusual ones like isocline and pseudoleucone. A complex mixture of alkanes was isolated as well. In 2010, we studied the meteorite again, and used spectroscopy this time, identifying 70 amino acids, for a potential of over 50,000 more unique molecular compositions. This leaves the possibilities that millions of distinct organic compounds exist just in this one fragment from space.
Later into the study the report found that these amino acids, were racemic and therefore formed in a natural manner because it's terrestrial proteins were all of the L-configurations. The L or (left) configuration - also known as chirality, is a mystifying biological event, where amino acids, the little building blocks of life tend to build in a left hand way and not right. The mirror-image asymmetry of life is one of the biggest mysteries in biology, but it also happens to be how life is built here on Earth. Scientists know that this bias encompasses the entire living world. When we try to duplicate this process in labs we can't do it. Labs generate both left-and right-handed molecules but when nature makes a molecule, the product is either left-or right-handed. All amino acids made in nature that are used to make proteins, twist to the left. And all of these little proteins and amino acids are what creates DNA and essentially what we are made of as well. It is not clear why nature elects a particular chirality, yet there are some organisms here that are symmetrical like flowers or the fivefold symmetry of a jellyfish. We are also a part of this chemical make-up with mirror like symmetry - for instance, our right hand to our left hand but yet its not universal thought our bodies. Pastuer at one time studied this as well, finding crystals of sodium ammonium tartrate could be separated into the left-handed and right-handed forms. The molecular asymmetry of natural molecules struck him as profound. If only he'd known about CM meteors, what would he think now?
This one little piece of rock from space, definitely made an impact. Lets just say a ripple, in how we understand the origins of life. Chirality in nature, and evidence struck upon us in 1969, leaves a few questions open, and envisages life on Earth as an extraterrestrial origin. This crack in our biological mirror suggests there is a potential relationship between life from outer-space and life on Earth. Could extraterrestrial meteors have brought a program with them, to make us, when they hit our planet long ago? The evidence to support the idea continues to beg the question. Also known as cosmic ancestry this is a alluring theory and one that continues to be debated alongside evolution based research. Evolution, gene regulation and how we became what we are is deeply connected to the idea that we are the result of materials sent from an unknown maker outside of our galaxy. Many scientists remain skeptical of this idea, while others look to the heavens to explain how this planet's biological bias first arose. The only way we can know for sure, is to set up our very own lab capable of evolution on its own which has never been accomplished so far.
Maybe this information is familiar to you, but the idea of cosmic ancestry is being investigated heavily and with great interest around the world. The debate continues but countless scientific papers and biological research are published that helps support the theory. The meteor impact is just a smoking trail so to speak. I don't want to lose anyone in the science but interstellar life and panspermia hypothesis gets pretty darn interesting when experts consistently publish research supporting evidence that our genes were programed before they were deployed on Earth, leaving no opportunity for standard darwinian trail-and-error. As it turns out, the latest research seems to point out that gene conversion keeps silent and protected over long periods of time. The stuff we used to call "junk" lies uncorrupted and protected over many generations confirming fundamental predictions of cosmic ancestry that explains life is older than Earth.
I recently came across an article that said science studies life like a book, looking at the ink and the paper the book is made upon, but sometimes misses the study of the author who wrote it. As an author myself I was drawn to that analogy. If life is a program or a book, then we must have one heck of a creative writer out there. I won't go further into that suggestion, but as far as the story of life, I tend to lean to the left. :)
Where do new genes come from? Geneticists in China and Canada offer an answer in a recentreport, "De Novo Origin of Human Protein-Coding Genes)(19 November 2011 )