A Gene Common to All Life on Earth Discovered Missing at Volcanic Environments
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June 13, 2012

A Gene Common to All Life on Earth Discovered Missing at Volcanic Environments

 

            Thebasicbuil

 

A protein, thought to be one of the fundamental building-blocks of life, is not present in certain volcanic single cell organisms. A team of scientists found another in its place. The missing protein, named SSB, performs an essential role binding DNA and protecting it from damage.

“All cells, whether they are microbial or human, have some things in common," said Malcolm White of the School of Biology at the University of St Andrews. "These are the fundamental components or building blocks which were present in the first cells and have been passed on over 3.5 billion years.However, we have discovered that a gene normally thought to be absolutely essential and conserved throughout every form of life, is in fact lost in one group of volcanic bugs, and replaced by a completely novel gene we have christened ThermoDBP.”

The discovery has ramifications for understanding about how life has evolved on earth.The new gene could have applications in biotechnology and the new scientific discipline of synthetic biology.

ssDNA-binding proteins (SSBs) based on the oligonucleotide-binding fold are considered ubiquitous in nature and play a central role in many DNA transactions including replication, recombination, and repair. We demonstrate that the Thermoproteales, a clade of hyperthermophilic Crenarchaea, lack a canonical SSB. Instead, they encode a distinct ssDNA-binding protein that we term “ThermoDBP,” exemplified by the protein Ttx1576 from Thermoproteus tenax.

ThermoDBP binds specifically to ssDNA with low sequence specificity. The crystal structure of Ttx1576 reveals a unique fold and a mechanism for ssDNA binding, consisting of an extended cleft lined with hydrophobic phenylalanine residues and flanked by basic amino acids. Two ssDNA-binding domains are linked by a coiled-coil leucine zipper.

ThermoDBP appears to have displaced the canonical SSB during the diversification of the Thermoproteales, a highly unusual example of the loss of a “ubiquitous” protein during evolution.

 

           ST Helens w purple flowers

The Daily Galaxy via St Andrews University and the Proceedings of the National Academy of Sciences (PNAS)

Image credit: with thanks to pixtus.com

Comments

It seems Jeff Goldblum's infamous quote from Jurassic Park holds completely true in the real world. Life finds a way to exist.

Very, very neat! But what I want to know is, how the heck do they get from volcano A to volcano B?

And what does this say about possibility for life elsewhere in this solar system?

Dr. J says that we are surprised beyond our wildest imagination. The fact that here on Earth that not all life follows the expected norms, and that organisms that live on the extreme don't have the same chemical make up as those who don't live on the extreme. There are many in the "scientific" community who have too many preconceived notions of what something should or should not be, for the basic premise of being a science is to look at something with an open mind; not a closed one. Yes, we are the dominate species with the right DNA sequence and the right protein ssDNA binding molecules, but who is to say that one day they make be the majority and we the minority?

Headline problems... and it worries me because of what it says of our respect of the scientific method.

If a gene is common to ALL life on earth and then turns up missing in a life form, then it's NOT common to ALL life. QED.

If a theory describes a phenomenon, behavior, etc and then an exception is discovered, the theory needs modification - it's inadequate and... wrong.

I'm in agreement with @kristianna27 - and it's permeating too much these days (from Climate Change to the big bang to now this gene story) - we invest too much of our own notions of how we think things should be and then try to twist the facts and ignore the exceptions.

So - we should respect science and the scientific method more and not dilute it (because then it becomes meaningless garbage).

The philosophy of science states nothing can be proven...only disproven. The closest we can come to acknowledging proof is "failure to disprove" or "fail to reject" a hypothesis or theory. A theory is not absolute...it is quite acceptable and even implicit in its meaning to be subject for modification. A scientific theory is an overall unifying principal that seeks to explain seemingly disconnected phenomena under a single, simple concept. Thus, the theory in question is not necessarily wrong, just in need of modification. Indeed, uncertainty is intrinsic to science. There is wisodom in knowing that we know nothing!

The headline should have read:
"A Gene 'Once Thought' Common to All Life on Earth Discovered Missing at Volcanic Environments"

Just more info to add to the mountain of understanding we already have about evolving life.


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