Wednesday, January 28, 2009

Artificial life?

by Martín Bonfil Olivera
Published in
Milenio Diario, Ja
nuary 28, 2009

At the beginning of the twentieth century, Russian Aleksandr Oparin and British J.B.S. Haldane proposed (independently) that the distinction between live and inert matter was only an issue of grade, not essence. This means that living beings could have been originated —without divine intervention— from inanimate matter (an idea already suggested by Darwin). From then, a dream of all chemists has been to create artificial life: to manufacture a living cell from only its essential components.

The possibility is still far away, but a recent paper by molecular biologists Tracey Lincoln and Gerald Joyce, from Scripps Institute in California, published on the January 8 electronic edition of Science magazine makes it a little bit more real.

Lincoln and Joyce started from one of the most currently accepted theories about the origin of life. The genome of all living organisms is made of deoxyribonucleic acid (DNA), a molecule shaped like a double helix that can copy itself, if it has help from the proper enzymes —molecular machines.

But there is abundant evidence that maybe the first molecule capable of auto-reproduction was not DNA, but its cousin, ribonucleic acid (RNA), a molecule that, as discovered in the 80s, can also act as an enzyme (catalyzing chemical reactions).

It is known that there are RNAs capable of cutting and pasting other RNA molecules. Lincoln and Joyce manufactured a pair of synthetic RNA that copy each other. Each molecule consists of two halves: the first RNA the two halves that form the second, and then, this one bonds the halves of another copy of the first one, just like the famous drawing by M.C. Escher of two hands drawing each other. While there is raw material (the four necessary pieces), the process can continue indefinitely, multiplying the RNA couples.

But not only that: Lincoln and Joyce also manufactured some variants of their RNAs and placed them in a "competition". The different available pieces formed new combinations and, after some time, the ones that reproduced faster were predominant in the solution. Evolution in a test tube!

Artificial life is still a dream, but the experiment proves that it is possible, at least in principles. Lets see what the future holds in store.

(translated by Adrián Robles Benavides)

To receive Science for pleasure weekly
in your email, subscribe here!


Contrasts

by Martín Bonfil Olivera
Published in
Milenio Diario, January 21, 2009

In his inaugural speech, President Barack Obama assured that his government will "restore science to its rightful place", and will "wield technology's wonders" to improve health and education and fight the energetic crisis.

He acknowledged, together with the importance and diversity of religion, the existence and rights of atheists: "We are a nation of Christians and Muslims, Jews and Hindus — and non-believers".

This respectful and inclusive vision contrasts with the intolerant and retrograde view presented last week on the World Family Congress, in Mexico, a view that Mexican President Felipe Calderon endorsed when he was there to inaugurate the event. With this, he violated the Mexican separation of Church and State, since he presented himself not as Mexican President but as a catholic citizen.

Other pearls of wisdom expressed in this meeting:

Javier Lozano Barragán, of the Pontifical Council for Health, said that the (Catholic) Church is worried because the predominant economical model causes family mothers to work, so they don’t put enough attention to their children: "Four words: less food, more attention".

President Calderón had the nerve of extending this ridiculous theory and stated that the source of violence and drug traffic is family disintegration… this theme has been sufficiently refuted —and ridiculed— by numerous analists.

Ennio Antonelli, President of the Pontifical Council for the Family, said that homosexuality is "contrary to the truth of human identity" and stated that "no one can deny being a man or a woman".

Of course, one of the agendas of this meeting was to violently disqualify any type of union between persons different from the traditional model of nuclear heterosexual family with children ("homosexuals constitute a transgression to the sense of love").

What is alarming is not only the ignorance that such ideas reveal, but that they are presented as "natural laws" (imposed by God, of course).

Maybe if the Vatican and the Mexican government were more respectful towards diversity and individual rights, and had a greater appreciation of science, our future would be more promising. Unfortunately, that's not the case.

(translated by Adrián Robles Benavides)

To receive Science for pleasure weekly
in your email, subscribe here!


Wednesday, January 14, 2009

Love and chemistry

by Martín Bonfil Olivera
Published on
Milenio Diario, January 14, 2009

Excess is usually bad, in science or in any other area. An example is the polemic essay (not scientific article) that biologist Larry Young published recently in Nature magazine (and that was reviewed in MILENIO Diario).

My colleagues Horacio Salazar and Braulio Peralta have already commented on this: Horacio thinks that "it is marvelous to imagine that the elegance of biochemistry is behind that vital motor", while Braulio thinks its "questionable".

Young proposes, using a very reasonable evolutionist logic, that the neuro-hormonal mechanisms that must underlie that complex and diverse human phenomenon called love (because we know that mind and emotions are products of the brain, not a spirit: if not, Alzheimer's disease wouldn’t cause the harm it does) must have evolved through already existing mechanisms in our mammal ancestors.

He postulates that the mechanisms by which the hormones oxytocin, in females, and vasopressin , in males, contribute to establish the bonds between parents and breed could have been adapted in the course of human evolution to form bonds between couples.

Up to this sentence, we are fine, although his conjectures regarding the possibility of future genetic love compatibility tests or drugs to facilitate attraction can be disturbing (he mentions them because, if he is right, we might have to make some decisions soon, as a society, about these issues).

What might be questioned is Young's reductionist vision. Its true that all mental or emotional states must have some neurological and, ultimately, chemical basis. But this does not mean love is "just chemistry". This is "dumb reductionism", because it is excessive. Phenomena like mind and conscience are no less real —and no less complex, far beyond mere chemistry or brains— just because their basis can be reduced to these elements. That would be like saying that TV series are "only electricity".

Reductionism is not a sin, if it works as a path to knowledge. But reducing love to "just chemistry" amounts to commmiting the sin of ambitious reductionism.

(translated by Adrián Robles Benavides)

To receive Science for pleasure weekly
in your email, subscribe here!



Wednesday, January 7, 2009

Darwin's year

by Martín Bonfil Olivera
Published on
Milenio Diario, January 7, 2009

Now that the Mexican independence bicentenary and Mexican revolution centennial are close, we should not forget that another bicentenary will be celebrated on February 12: the birth of Charles Darwin.

Darwin's importance for science and for the whole of today's culture cannot be exaggerated. His central idea —natural selection as the mechanism that allows us to explain the evolution of living beings and their marvelous adaptations to the environment— has been discovered to have applications in a lot of fields that he would've probably never imagined.

Natural selection is based on the fact that organisms reproduce on unequally: some leave more descendants than others. There can be several reasons (higher physical resistance, better use of nutrients, greater fertility, descendants that are more resistant…), but most of these characteristics can be inherited. I. e., they're genetic factors.

This simple fact gets the Darwinian machinery going: descendants of advantageous organisms will inherit their advantages, and little by little these will be predominate in the population. When enough generations have passed, the totality of a species could have changed —evolved— to be better adapted to its environment. And since environments are always changing, evolution never stops. Its slow and blind accumulation of adaptations achieves the surprising designs whith which nature astonishes us.

But not only living organisms can evolve. There are a lot of other systems in which information is passed from a "generation" to another with small changes, and this immediately allows for evolution to take place. Jokes are a good example: the ones that trigger laughter are repeated by the listener, in most cases, with little changes that, if they improve it, will enhance their dispersion (if they screw it up, they can cause the joke to become "extinct").

Language, fashion, technology, ideas, religions, computer programs —and virus— and a lot of other thing also evolve by natural selection. Today we live in a more and more Darwinian world.

In future collaborations we will explore some of these ramifications. In the meantime, let us celebrate, together with the International Year of Astronomy, Darwin's year.

(translated by Adrián Robles Benavides)

To receive Science for pleasure weekly
in your email, subscribe here!