Archive for the ‘Biochemical Design’ Category

A Case for Intelligent Design, Part 1 (of 4)

Thursday, January 22nd, 2009

Posted by Fazale ‘Fuz’ Rana, Ph.D.

Scientists One Step Closer to Artificial Life and the Best Case for ID

Photo of Fazale 'Fuz' RanaMary Shelley’s famous Gothic horror story presents a fascinating character: Victor Frankenstein. As a burgeoning scientist, Victor becomes obsessed with discovering the “principle” that distinguishes life from inanimate matter. After many long hours of study and laboratory work he uncovers “the cause of generation and life,” and becomes “capable of bestowing animation on lifeless matter.”

Frankenstein exercises his newfound ability by bringing a humanoid monster to life, only to abandon it in disgust. Victor’s moral failings lead to several tragic deaths at the hands of his creature, including those of his brother, his best friend, and, later, his wife on their wedding night. Even though the scientist and the creation are somewhat sympathetic figures, it’s not clear who’s the true monster—Victor, the creature, or both.

If there is a real life Frankenstein, he might very well be Craig Venter.

Venter stands as perhaps one of the most important scientists in the last decade or so. (In 2008, Time magazine voted him one of the world’s 100 most influential people.) As a major player in the emergence of the science of genomics, he is a scientific maverick who thinks big and has little patience for the red tape and bureaucracy that characterize many scientific programs. And like Victor, he is a polarizing figure, much admired and much hated by people within and outside the scientific community.

Recently, Venter founded a company called Synthetic Genomics. As with Shelley’s protagonist, Venter wants to create life in the laboratory. The new company is devoted to creating artificial, nonnatural life microbes that have commercial utility, particularly for the production of ethanol, hydrogen, and other forms of renewable energy. Once again, Venter has generated a mixture of excitement and horror among the scientific community, and the public at large.

Scientists like Venter who pursue the creation of artificial and synthetic life claim that these novel life-forms will benefit humanity. If they accomplish the desired breakthrough, it could go a long way toward resolving the energy and climate crises.

The very real prospect of scientists creating life in the lab raises all sorts of theological questions. Should human beings “play God”? Some conservative Christians worry that the genesis of novel life-forms by human hands eliminates the need for a Creator by substantiating the evolutionary paradigm. Many theists and atheists, alike, believe that if scientists can create life in the lab, then there is nothing special about any life. Therefore, the origin-of-life could have easily taken place on the early Earth without God’s necessary involvement.

The latest work by Venter’s team stands as another milestone in the quest to create an artificial life-form in the lab. Ironically, instead of supporting an evolutionary origin of life, this research demonstrates that life’s beginnings and transformation cannot happen apart from the work of an intelligent agent.

This week I will discuss the progress Venter and his team at Synthetic Genomics have made toward achieving their goal. In the next couple of weeks I’ll describe the details of their most recent accomplishment and will eventually explore the implications of this work for the intelligent design (creation)/evolution controversy.

The Path to Artificial Life

Venter and his coworkers became interested in creating artificial life as an outgrowth of another project. Initially, they were interested in determining the minimum genome for life. The term “genome” refers to an organism’s entire hereditary information, stored in the nucleotide sequences of DNA. The information housed in genomes exists in units called genes. These units contain the information that the cell’s machinery uses to make proteins.

Proteins take part in virtually every biochemical process and play critical roles in nearly every cell structure. Cataloging the number and types of proteins present in an organism gives biochemists important insight into its structures and operations. Venter’s team hopes that identifying the minimum genome will provide them with an understanding of life at its most fundamental level.

In their attempts to reach that target, Venter’s group has focused attention on a bacterium called Mycoplasma genitalium. This microbe has one of the smallest, if not the smallest, genome known to scientists. M. genitalium parasitizes the human genital and respiratory tracts. Its genome possesses about 480 gene products. Because its genome is so extensively pared-down, it’s ideally suited as a model system to determine the absolutely indispensable requirements for life—the “non-negotiable” biochemical systems that must be present for an entity to be recognized as a form of life.

The researchers reasoned that it is quite likely that the bare essential genome is much smaller than 480 gene products. It turns out that a significant fraction of this parasite’s genome is dedicated to mediating interactions between the parasite and its host and can be considered as nonessential to a strictly minimal life-form.

Using an experimental approach, Venter’s team worked to ascertain the minimum number of genes needed for life. Their protocols involved both the random and systematic mutation of M. genitalium genes to determine those that are indispensable for life. (Biochemists refer to these procedures as knock-out experiments.) If a gene is nonessential, M. genitalium will still grow after the gene is mutated.

Once the essential or minimum gene has been determined via the knock-out experiments, the scientists hope to confirm their result by preparing a synthetic minimal genome and introducing it into a cell to see if the cell with the transplanted genome grows. They realized that in the process of identifying the minimum genome, they came just a few short steps away from making artificial life in the lab.

Steps to Creating Artificial Life

Venter and collaborators’ approach to creating an artificial life-form is called a top-down strategy. It involves starting with a naturally occurring microbe and stripping it down to its bare genetic and biochemical essence, and then modifying it by adding nonnative genes to the minimal genome to generate a nonnatural form of life.

The major stages in this effort involve:

  • systematically eliminating genes from the M. genitalium genome to identify all the essential genes;
  • synthesizing the building blocks of DNA from the minimal genome from nucleotides,;
  • introducing the minimal genome into the cytoplasm of a M. genitalium cell that has had its original genome deleted;
  • growing and then replicating the organism harboring the synthetic genome.

    Once these steps are accomplished, a nonnatural organism, called Mycoplasma laboratorium, will have been created. At this point, the researchers will have the genetic foundation in place to build an organism with any biological properties they desire. For example, they currently plan on adding genes to the minimal genome that will produce proteins that can generate hydrogen.

    A Brief Progress Report

    To date Venter’s team has made remarkable progress toward their goal of producing Mycoplasma laboratorium. They have identified the essential gene set (which consists of about 380 genes). They have also synthesized from scratch the entire genome of a wild-type M. genitalium and cloned it (made copies) in yeast. Additionally, they have transferred the wild-type genome of M. genitalium into a closely related Mycoplasma species.

    The next step is for the researchers to put all of these steps together to synthesize, clone, and introduce a synthetic minimal genome into M. genitalium.

    Though this last milestone seems rather trivial, it is technically quite challenging. Next week I’ll illustrate these technical challenges by describing their most recent efforts to improve upon the efficiency of synthesizing and cloning a synthetic genome in yeast, a vital step in “bestowing animation on lifeless matter.”

  • Winding Up Paley’s Watch, One More Time

    Thursday, December 11th, 2008

    Posted by Fazale ‘Fuz’ Rana, Ph.D.

    New Discovery adds to Evidence for Biochemical Design

    Photo of Fazale 'Fuz' RanaWhen I was growing up, it was still common for people to have mechanical watches that had to be wound up periodically. Battery-powered, digital watches were a rare sight.

    This week, I would like to return to the past and revisit an earlier article I wrote on biochemical evidence for intelligent design. This evidence centers on the discovery of a protein complex found in cyanobacteria that functions, literally, as a mechanical watch in both a structural and operational sense.

    This watch regulates metabolic processes such as nitrogen fixation and photosynthesis as well as overall gene expression within the cyanobacterial cell in response to light-dark cycles (day and night).

    As I wrote earlier, the existence of a mechanical time-keeping device inside cyanobacteria is provocative in light of William Paley’s Watchmaker argument for God’s existence. The strength of this argument rests on the machine-like characteristic of the biochemical time-keeping ensemble of proteins. A recent review article published in Science summarizes the current understanding of the protein complex that keeps biological time, highlighting its mechanical properties.

    With discoveries like these, the future looks bright for the Watchmaker analogy.

    DNA Soaks Up Sun’s Rays

    Thursday, November 20th, 2008

    Posted by Fazale ‘Fuz’ Rana, Ph.D.

    DNA Optimized for Photostability, Adds to the Evidence for Design

    Photo of Fazale 'Fuz' RanaAbout ten years ago my family and I moved from Ohio to sunny Southern California. I don’t think I could ever go back. I have no desire to experience ever again the frigid winters and humid summers that are major parts of living in the Midwest.

    The year-round beautiful weather in the “southland” makes it possible to enjoy many carefree hours outdoors. But it also prompts some concerns about spending too much time in the sun. Soaking up too many of the Sun’s harmful rays can cause long-term damage to the skin—unless, of course, one lathers on the sunscreen.

    Like Southern Californian sun “worshippers,” DNA also faces problems with short wavelength UV-radiation from the sun. This radiation can damage this all-important biomolecule. Fortunately, biochemists have discovered that DNA has unusual photostability. Scientists believe that specific structural features of DNA make it resistant to the harmful effects of the sun. It’s as if DNA has its own built-in sunscreen.

    New research has uncovered some of the specific aspects of DNA structure that contribute to its unusual photostability, and—with this insight—add to the weight of evidence that biochemical systems are the work of a Creator.

    The Structure of DNA

    DNA consists of chain-like molecules known as polynucleotides. Two polynucleotide chains align in an antiparallel fashion to form a DNA molecule. (The two strands are arranged parallel to one another with the starting point of one strand in the polynucleotide duplex located next to the ending point of the other strand and vice versa.) The paired polynucleotide chains twist around each other to form the well-known DNA double helix. The cell’s machinery forms polynucleotide chains by linking together four different subunit molecules called nucleotides. The nucleotides used to build DNA chains are adenosine, guanosine, cytidine, and thymidine, famously abbreviated A, G, C, and T, respectively.

    The nucleotide molecules that make up the strands of DNA are, in turn, complex molecules consisting of both a phosphate moiety, and a nucleobase (either adenine, guanine, cytosine, or thymine) joined to a 5-carbon sugar (deoxyribose).

    Repeatedly linking the phosphate group of one nucleotide to the deoxyribose unit of another nucleotide forms the backbone of the DNA strand. The nucleobases extend as side chains from the backbone of the DNA molecule and serve as interaction points when the two DNA strands align and twist to form the double helix.

    When the two DNA strands align, the adenosine (A) side chains of one strand always pair with thymidine (T) side chains from the other strand. Likewise, the guanosine (G) side chains from one DNA strand always pair with cytidine (C) side chains from the other strand.

    The Photostability of DNA

    As I pointed out in chapter seven of The Cell’s Design, biochemists have known for a while that the particular nucleobases found in DNA display ideal photophysical properties. Even though DNA routinely experiences photophysical damage, it could be far worse. It turns out that the optical properties of the bases found in nature minimize UV-induced damage. These nucleobases maximally absorb UV-radiation at the same wavelengths that are most effectively shielded by ozone. Moreover, the chemical structures of the nucleobases of DNA allow the UV-radiation to be efficiently radiated away after it has been absorbed, restricting the opportunity for damage.

    To gain further insight into the structural features of DNA that contribute to its photostability, researchers from Germany prepared a number of model DNA compounds. It turns out that the molecular interactions that promote the pairing of the side groups in the DNA duplex help dissipate absorbed light energy. Variation of the nucleotide sequences in the strands of DNA also plays a role in photostability. This variability prevents long-lived excited states from forming when UV-radiation is absorbed by DNA.

    It appears that DNA has been designed to have optimal photostability. This property is critical for DNA’s role in the cell as a data storage system. DNA harbors the information needed for the cell’s machinery to make proteins. It also houses the genetic information passed on to subsequent generations. If DNA isn’t stable, then the information it harbors will become distorted or lost. This will have disastrous consequences for the cell’s day-to-day operations and make long-term survival of life impossible.

    As I discuss in The Cell’s Design, photostability is not the only feature of DNA that has been optimized. Other chemical and biochemical features appear to be carefully chosen to ensure its stability; again, a necessary property for a molecule that harbors the genetic information.

    Optimized biochemical systems comprise evidence for biochemical intelligent design. Optimization of an engineered system doesn’t just happen—it results from engineers carefully optimizing their designs. It requires forethought, planning, and careful attention to detail. In the same way, the optimized features of DNA logically point to the work of a Divine engineer. It appears as if someone carefully designed the structure of DNA to spend many long hours in the sun.