The membrane of your cells and of mine is the soul and skin of you and me. It has far more to do with who we are than we have ever conceived.

The membrane wrapped around each of your cells is a molecular mesh like a chain link fence. It begins with cooperative assemblies of atoms--rings or strands of carbon, hydrogen, and oxygen grouped as monosaccharides--sugars. These, in turn, link arms in long circular hoops--as polysaccharides. These polysaccharide chains circling the cell from side to side are cross-linked by short up-and-down polypeptide strands, creating a fishnet-sphere of molecules known as peptidoglycans. The peptidoglycans are linked and knit into one giant, continuous macromolecule.

That megamolecule's fabric forms a sack...a bubble-bag sheathed by coalitions of carbon, hydrogen, and oxygen--a coat of lipopolysaccharides. The interior of the peptidoglycan sack is lined with a plasma membrane, and voila, you have a bacterial membrane, the envelope that gives a bacterial cell its shape and integrity.

This massive nested hierarchy of emergent properties is not constructed or coded for by genes. It is as independent and as important to cell duplication as the gene team of the genome. Though let me not mislead you. This outer shell interacts crucially with genes to bring each cell to life.

The peptidoglycan fabric must go through 3 million additional stitches to allow the cell to bud into two daughter cells.

There is an element of immortality to this weave. From the very beginning of life, each cell has extended its macromolecular envelope, then, generated a wall that could be split in two--a septum--and has given its daughters the two garments cut from the same cloth--one to each--as a trousseau.

Any cell that has the misfortune of breaking the chain, of developing a rip or tear, of accidentally rupturing the unending weave of membrane fabric, fails to exist. Its pressurized contents spill out, destroying the social integration that keeps a cell alive. So just as only genes can make new genes and just as only cells can make new cells, only the weave of membrane molecules that started with the first cells roughly 3.5 billion years ago can knit new cellular envelopes. And only these envelopes can house the genes and macromolecular communities of cells.

In a sense the Greeks had it right when they portrayed the fates as three sisters--Lachesis, Clotho, and Atropos--who twist a thread, spin it out, then snip it. But life is more than just a thread. It is a continuously expanding cell-membrane tapestry.

That fabric--all an extension of the first that ever was--has now girdled the planet with its progeny--bacteria, beasts, and human beings. And we have found new ways to weave ourselves together, via webs of ideas, worldviews, technologies, and via socially ravenous genes. Those genes, in turn, encode us to be links in a social fabric that, thanks to our ancestor worship, among other things, keeps knitting and purling us in a continuous cloth of culture that goes back at least 35,000 years.

Like cells, we differentiate. We do it as individuals. We do it as subcultures. And we do it as nations and civilizations. But we all carry our heritage as new stitches looped from and looping back into the weaves with which we all began. You and I are weaves of carbon, hydrogen, and oxygen. We are knots of sugars, polysaccharides, and peptidoglycans. You and I, trilobites and dinosaurs, George Bush, Osama Bin Ladin, and Kim Jung Il, mosquitoes, your houseplants, your cat, the fish you shared with her last night, the bacteria in your gut that helped you digest your dinner and the bacteria waiting someday to attack you, all are patterns cut from one continuous bolt of a single self-stitching macromolecular sheet.

We squabble, bite, make war and fight, but we are more together than we have ever dreamed.

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