March 13, 2010 | David F. Coppedge

Fruit Flies: From Darwin to Design

The fruit fly Drosophila melanogaster is an icon of evolution.  Since the 1930s these poor little bugs have been mutated endlessly and watched for signs of Darwinian change.  So far, though, only useless mutants, unable to survive in the wild, have been produced.  Recently, scientists seem more enamored with their design.  Two recent articles had nothing to say about evolution but a lot to say about the amazing ways they are put together.  They are so well put together, in fact, that they put humans to shame in some ways – not only because they can fly and we can’t.

  1. Fly eye:  Did you know fruit flies have better color perception than we do?  Science Daily said that scientists studying phototaxis (attraction to light) in Drosophila found their 8 photoreceptors produce different responses in behavior.  One of the study authors pointed out, “This simple insect can achieve sophisticated color discrimination and detect a broader spectrum of colors than we can, especially in the UV.”
  2. Fly fountain of youth:  Science Daily reported on work to study how fruit flies overcome aging.  Scientists at UC San Diego identified a protein named Sestrin that “serves as a natural inhibitor of aging and age-related pathologies in fruit flies.”  The structure and biochemical function of this protein is “conserved” (i.e., unevolved) between fruit flies and humans – meaning that we may owe the ability to live longer, healthier lives some day to research on these tiny insects.  Experiments that reduced Sestrin in the flies produced stress and deformities.  “These pathologies are amazingly similar to the major disorders of overweight, heart failure and muscle loss that accompany aging in humans.”
        The pathologies appear to arise by disrupting an important “quality control” mechanism called autophagy, the article explained.  The team is trying to find out if “proper Sestrin expression will provide the explanation to some of the currently unexplainable degenerative diseases associated with old age.”  One researcher hoped for good fruit from these experiments: “Maybe one day we will be able to use Sestrin analogs to prevent much of the tissue failure associated with aging, as well as treat a number of degenerative diseases, whose incidence goes up with old age, including sarcopenia and Alzheimer’s disease.”
  3. Fly time:  Oregon State is studying the fruit fly biological clock, reported Science Daily, in hopes of helping humans find the “key to better health and a longer life.”  A properly-functioning biological clock is important in preventing damage from oxidative stress.  The article noted that the genes for the fruit fly clock are essentially the same as in humans, having been “conserved [unevolved] through many millions of years of evolution.”  Obviously some other things have not been so conserved.  Most of us don’t resemble them much.
  4. Fly power:  Bodybuilders, be humble before the fruit fly: on your scale, they could bench press triple your personal best – for more reps, too.  PhysOrg noted that the muscles in these tiny insects are among the strongest in the animal kingdom (ounce for ounce, that is).  Frank Schnorrer of the Max Planck Institute said of their flight muscles, “They are able to produce 100 watt per kilogram muscle mass and that over a long period of time.  Bodybuilders and Tour de France riders can only dream about such a performance.  They steadily manage about 30 watt per kilogram muscle mass.”
        About 2000 genes in the fruit fly genome of 12,000 genes are involved in the production of these flight muscles.  Schnorrer remarked, “It is fascinating how the genetic programme of an organism is able to produce such different cell types out of identical precursor cells.”  Live Science posted a video last month showing how the fruit fly’s supercharged muscles ramp up during flight.

Humans share some of the same genes with fruit flies.  That’s leading to some other scientific design-based scientific research: using Drosophila as a model organism to understand the structure and function of genes for muscles, so as to produce cures for disabilities like muscular dystrophy.  “In the future, insight into such connections may help to detect and treat muscle diseases individually,” Schnorrer said, without a word about Darwin.

When you approach a scientific problem with design in mind, you have different goals and methods than a Darwinian does.  You attack the problem assuming there is a good design that needs to be understood.  Then, you have a goal of improving human life by applying what is understood to real problems we face.
    One of the most amazing stories we ever reported on this subject was by Michael Dickinson of Caltech back on 12/08/2003.  We urge you to revisit that entry now to be convinced once for all that design-based science is vastly superior to zapping creatures in the vain hope of finding something to offer Charlie.  Thinking about all that power and design in a tiny little fly is enough to turn a child into an enthusiastic scientist – the kind that would sign a growing list.

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