Gasoline prices, house prices, and presidential political statements are not the only things rapidly shifting this summer Ð so is genetics.  A recent Canadian study highlighted in the Economist, argues that sudden, interspecies genetic transfer has occurred in fish. This research finding in search of a mechanism may ultimately change our view of what a species is Ð including our human kind.

         Antifreeze is a group of chemicals we believe belongs in cars or motorcycles, which is correct if youÕre not a fish.  In northern climes sea salt causes water temperatures to decline to below zero centigrade. Without a way to resist internal freezing, you die.   If youÕre a whale, you possess acres of protective fat, whose attractive energy, food, and light uses has nearly caused whalesÕ extinction.

         Fish donÕt have so much fat.  Ice crystals quickly form in their blood.  To survive cold waters, theyÕve developed proteins that control the size of ice in their arteries.  Special genes make these antifreeze proteins.

         Kingston, Ontario is a small northern city better known for its huge prison than excellent QueenÕs University, where researchers found out something special about these fish antifreeze genes. Studying herring, smelt, and the extraordinary, leafy and horror movie ready sea raven, they discovered that anti-freeze genes across the three species were virtually identical. 

         That congruence is not supposed to happen.  Every species slowly builds up its own genetic inheritance, using sexual or asexual reproduction to transfers genes to the new generation.  The hemoglobin molecule in orangutans and chimpanzees is similar to ours, but there have been many changes since our evolutionary paths separated millions of years ago.

         The fish antifreeze genes were so similar they looked like they might have been ordered from a catalogue. A spectacularly successful series of genes somehow spectacularly jumped from one species to another.

         How?  Part of being a species means you donÕt cross reproduce.  Dogs donÕt mate with cats. The researchers postulate inter species sperm going astray in the ocean, fertilizing already fertilized eggs, but that explanation may not hold water.  Something strange is afoot.
        
The Human Superorganism
          
                   We may discover alternate explanations by looking at the 100 trillion or so other organisms that live within or on your body.  Genetic ÒpromiscuityÓ is far better tolerated among bacteria and viruses, ÒsimpleÓ organisms which often pass genetic material from species to species.  We can recognize how common this event is with the recent, unhappy realization that anti-malarial drugs are causing resistance to drugs which fight bacteria. 

         Chloroquine is an old anti-malarial, ineffective against new strains of the disease but helpful in preventing illness. Researchers received a shock when they discovered many children given chloroquine malaria prophylaxis suddenly developed antibiotic resistance to fluoroquinolones, the newest large antibiotic group.  None of the kids had ever seen a single dose of a fluoroquinolone antibiotic, yet the chemistry of chloroquine was apparently close enough to induce bacterial genetic resistance.

This is scary. For some illnesses, fluoroquinolones are all we have.  With the increasing virulence of methicillin resistant staphylococci and clostridium difficile, tens of thousands of Americans die each year from bugs we can barely control.

         Bacteria and viruses exchange genetic material with more than each other.  Though surveys vary, a large minority of your genetic material appear to originate in viruses.  Some estimates put genetic material from retroviruses, which shuffle RNA to DNA and include HIV, as making up 8-12% of the human genome.  Viruses have been playing around in the human genome well before there were humans.

         The new antifreeze gene finding argues species inviolability is not what we thought.  You are a superorganism with ten times as many cells (if you count viruses) from species other than your human ones.  We are familiar with bacteria and viruses rapidly shift genes amongst themselves, but what if theyÕre also moving material into us that comes from yet other species?

         For a world savaged throughout history by arguments over racial and ethnic purity, this is not a simple question.  Certainly the organisms that live in and on us have changed our genes, modified our immune systems, and powerfully altered our metabolism.  Yet it may be these organisms are more protean still, shifting genetic material around as if DNA were letters in some cosmic alphabet that can be mixed and matched at will.  Sexual reproduction has certainly transferred human genes far and wide, making us, in species terms, remarkably alike.  Yet it now appears that other species may have joined in the work.

         Genetic engineering has not been occurring for decades, but for eons.    We need to know what these mechanisms are and how they work.  Once understood, we will know more both about disease and what we are.

         Nature is, as usual, ahead of us.  ItÕs just a matter of how far.

Dr. Matthew Edlund practices sleep medicine and psychiatry in Sarasota.  His new book, Designed To Last, is available online. He can be reached at 365-4308 and via his Web site at doctoredlund.com.