13 Things That Don't Make Sense (10 page)

Soap molecules are based on triglyceride molecules—fat, essentially—but with distinct properties at each end of the molecule.
One end loves water. The other hates it. Put them in water, and the molecules arrange themselves rather like the petals of
a flower, with the water-loving ends facing out into the water, and the water-hating ends in the center. Oil and grease molecules
get trapped at the center of each “flower” and are carried away from whatever it is they were clinging to.

The reason for choosing what is little more than a ball of fat (in fact, they are known as fatty acids) as a basis for the
next generation of life is simple: it provides a useful container. In water it creates a neat, self-contained structure that
sits happily in the test tube. All it needs now is some genetics.

The Los Alamos Bug’s genetics don’t involve DNA. Instead it has PNA. The
P
stands for
peptide
: a short chain of amino acids, the building blocks of proteins. PNA, like DNA, is composed of two intertwined strands of
amino acids but is much simpler to make. It also doesn’t carry any electrical charge, which means it will dissolve in the
fat; PNA embeds itself in the oily drop that defines the Bug, and waits for the chance to replicate.

That chance comes when things get hot. Above a certain temperature, the double strands of PNA separate. This exposes small
electrical charges on some parts of the acid chain, and these charges are attracted toward the water. The chain itself, the
backbone of the Bug’s genetics, remains in the oily drop, but the electrical charges pull it to the edge. Here they encounter
short acid chains, even shorter than the PNA, that Rasmussen and his team plan to leave floating around in the water—a kind
of life support system. Some of them will bond to the “bases” of the exposed PNA strands; if a few are of the right kind,
the PNA strand will find itself paired up into a new double strand. Its charges neutralized, it will dissolve back into the
oily drop. As the temperature changes, the whole thing will happen again and again—the Bug’s genetics will be constantly replicating—with
a chance of interesting mutations at every turn.

Not that it’s a done deal. Rasmussen’s team has only got as far as having growth and division; there’s no gene replication
as yet. Nonetheless, Rasmussen is convinced that when it all works—and it is when, not if, he says—the Bug will be alive.

Well, sort of. He concedes that if you define
life
as “life as we are,” as we know it, then it’s not life. That would take many, many years, he says; a cell is an immensely
complicated system, and we don’t know the half of it yet. Rasmussen is convinced, though, that by all working definitions
the Los Alamos Bug will be alive.

It will, for instance, have a rudimentary metabolism that makes it reproduce. Some of the short peptide chain feedstock floating
in the water will have light-sensitive molecules attached to one end. These molecules will make the chain electrically neutral
and thus fat soluble; the Bug will end up “ingesting” these peptide chains. When day breaks, however, light will break the
light-sensitive molecules off. The chains will be left with a net electrical charge that will cause them to seek out the charge
in the surrounding water—they will migrate to the surface membrane of the Bug. As the light levels increase, and more and
more of these chains try to reach the surface, there simply won’t be enough surface. The drop, Rasmussen says, will split
in two. It will replicate. The way the whole thing is designed means that the PNA’s electrical properties stop these feedstock
molecules from becoming involved in the Bug’s genetics, keeping the process of growth and genetic mutation nicely separate.

It is still a struggle to imagine that ball of fat as being alive, though. Indeed, the
Nature
editorial questioning the value of a definition of “life” also questioned whether any of the attempts to build organisms from
scratch can really be regarded as “creating life.” And, looking at some of the projects competing with Rasmussen’s, we are
tempted to answer no. Take Craig Venter’s project, for example.

Though it is received wisdom that nothing good can come of a urinary tract infection, Venter, the man behind the private endeavor
to decode the human genome, might disagree. Venter is also on life’s case, and his project is attempting to elucidate the
mysteries of life by working on a bacterium that makes it burn when you pee.

Mycoplasma genitalium
was first discovered in someone’s urine in the early 1980s; the patient was suffering from an affliction called nongonococcal
urethritis. It turned out that the organism responsible, which lives in human genital tracts, has the smallest genome on the
planet. Where humans have around 30,000 genes,
M. genitalium
has 517. Even then, around 300 of those seem to do nothing useful.

Venter headed the team that first sequenced its genome in 1995. The organism’s relative simplicity inspired him to strip it
down to its bare essentials and see what it really needs to survive. Once its genome has been reduced to the bare minimum,
Venter will have an idea of what is required for life, he says. It will also provide a useful biofactory; he plans to insert
other genes into the bacterium that could enable the organism to perform tasks like synthesizing insulin. That is undoubtedly
why Venter is attempting to take the controversial step of patenting the
minimal genome
.

He has worked out the genes required for this minimal organism, synthesized them. The plan, at the time of writing, is to
implant them in a bacterial cell that has had its own genome removed. He has already proved his team can carry out such a
genome transplant in principle, so there is no technical hurdle remaining. Nevertheless, although it is vaunted as a step
on the path to creating life, what Venter is creating is essentially a new species of bacterium rather than new life. David
Deamer, a biophysicist at the University of California, Santa Cruz, goes even further. The creature Venter’s team are trying
to produce, he says, is really just a “radically engineered organism.”

The same can be said for an effort under way in Rome, under the leadership of Pier Luigi Luisi. Luisi’s “minimal cell project”
starts with a vesicle, a kind of container used for transporting stuff around within cells, and will add various chemicals
and components until something like a full working cell appears. At Harvard, Jack Szostak is also planning to fill a vesicle
with biological material, this time to see when its starts replicating. Szostak is happy to admit it’s a long-term project
with no definite end in sight; he’s been saying proper artificial replication is ten to twenty years off for ten to twenty
years now.

Even if Venter’s eviscerated cells or Rasmussen’s ball of fatty acids in a test tube end up “alive,” that doesn’t necessarily
tell us anything about this thing we call life. So where do we stand? Christian de Duve, who was educated by Jesuits, talks
of a
cosmic imperative
, where life arises (when conditions are right) as an inevitable consequence of the laws of physics. That’s essentially what
Rasmussen says too: that life is just a very efficient way of processing energy. The trouble with this view is that it still
leaves us without a clear idea of what life is and what made it appear on Earth. Rasmussen counters this by arguing that the
individual element and the overarching phenomenon are two different things; looking at a car doesn’t tell us anything about
traffic jams, he points out.

And there, perhaps, is where the anomaly of life leads us to a scientific revolution. If reductionism is a dead end, maybe
we should turn around and head off in the opposite direction.

IN
August 1972 the Bell Labs physicist and Nobel laureate Philip Anderson published an essay in the journal
Science
. Anderson has always been a provocative voice, and never more so than in this piece. It was titled “More Is Different,” and
it makes inspiring reading.

Drawing on his experience of science as a process, Anderson forcefully makes the point that the behavior of large and complex
groups of particles cannot be understood by applying our knowledge of the properties of a few particles. In other words, as
with the difference between cars and traffic jams, More Is Different. This, he asserts, is a real principle, not merely an
observation. At each new level of complexity, “entirely new properties appear, and the understanding of the new behaviors
requires research which I think is as fundamental in its nature as any other.”

If we are to understand the cosmos we live in, he says, we’re going to have to abandon reductionism; the ability to reduce
everything to simple fundamental laws does not necessarily give us the ability to start from those laws and reconstruct the
universe. “In fact, the more the elementary particle physicists tell us about the nature of the fundamental laws, the less
relevance they seem to have to the very real problems of the rest of science.”

The thing is, we are used to breaking things up to understand them: the lump of metal breaks down to atoms, the atoms break
down to nuclei plus electrons, the nuclei break down to protons and neutrons, which in turn break down to quarks, and so on.
That’s how science has progressed over the last century, and what a success story it has been. Why would we change the methodology
now?

Because otherwise we are not going to progress, is Anderson’s retort. We are plagued by arrogant molecular biologists who
“seem determined to try to reduce everything about the human organism to ‘only’ chemistry,” Anderson says. “Surely there are
more levels of organization between human ethology and DNA than there are between DNA and quantum electrodynamics.” Each level,
he suggests, might require a whole new conceptual structure.

Anderson concludes his argument with recourse to a historical dialogue:

F. Scott Fitzgerald: “The rich are different from us.”

Ernest Hemingway: “Yes, they have more money.”

We all know that extreme wealth does not come with a rule book that dictates a strikingly different set of behavioral norms.
And yet we have all seen the evidence that such behavioral differences do exist. Similarly, there is no way, Anderson says,
to use the reductionist method to work out how and why certain phenomena have come into being; we must instead observe where
these “emergent” behaviors arise and try to work out the principles that caused such emergence.

More than thirty years have passed, and still almost no one is listening. At the turn of the millennium, though, two more
physicists took up Anderson’s stance. The Nobel laureate Robert Laughlin and the distinguished physicist David Pines published
a paper in the
Proceedings of the National Academy of Sciences
. Citing Anderson’s cry that More Is Different, they declared that the central task of physics in our time “is no longer to
write down the ultimate equations but rather to catalogue and understand emergent behaviour in its many guises, including
potentially life itself.”

The basic idea of emergence is that when a system is composed of many interacting parts, it will organize itself in ways that
seem surprising; all the various interactions between the parts will lead to behaviors that look astonishingly complex. The
chemist George Whitesides showed this by putting small iron ball bearings into a Petri dish, then putting a rotating bar magnet
under the dish. The balls self-organize into concentric rings, each of which rotates. There are physical rules behind this
behavior—having to do with magnetic interactions and the way each ball is affected by friction—but we could never hope to
elucidate them. Perhaps, though, we could find the more general “organizing principles” behind the emergent behavior and take
those as a set of rules to be consulted when analyzing similarly complex systems. The idea is that other complex and seemingly
inexplicable phenomena, such as protein-folding and high-temperature superconductivity, might also be described by these rules:
find one, and we might be able to unlock a rich seam of phenomena—including the enigma of life.

The people involved in this effort certainly talk a good game. According to the Santa Fe complexity theorist Stuart Kauffman,
“organisms are not just tinkered-together contraptions, but expressions of deeper natural laws.” To Laughlin, those deeper
laws, the principles of organization, are the “true source of physical law, including perhaps the most fundamental laws we
know.”

In 1999 Laughlin and Pines established the Institute for Complex Adaptive Matter at the University of California. The idea
was to bring scientists together to look at the various inexplicable “emergent phenomena” they have identified and try to
work out the principles behind them. They must have been doing something right, because in 2004 the National Science Foundation
began to fund the work.

The idea that a whole new branch of science is opening up is certainly inspiring and exciting; work out what makes those little
balls form their rotating rings, and we might not merely solve the enigma of life but also discover the true nature of dark
energy and from whence come the variations in alpha. The reality, however, remains somehow disappointing. As yet there have
been no breakthroughs or insights that have changed our view of the universe. Neither is there any evidence that many scientists
are abandoning the reductionist approach. We have no clue what the emergent laws might look like. That doesn’t mean Anderson,
Pines, Laughlin, and Kauffman are wrong, but it does mean the enigmas they might solve are likely to remain unsolved for a
while yet.

LIFE
, for now, stubbornly remains an anomaly: something unique, mysterious, and—put simply—“special.” It’s a situation that doesn’t
sit well with science. Most scientists, for good reason, don’t want life to be known as something special, the result of a
“vital spark” or, as the book of Genesis would have it, a mystical quickening due to the breath of God. Being somehow special
doesn’t fit with the overarching theme of science in the twenty-first century, a theme that makes a point of how insignificant
we are. Carl Sagan perhaps said it best.