Blind Cavefish Shed Light on Creation | The Institute for Creation Research

Blind Cavefish Shed Light on Creation

How do fish that can see make the switch to blind cavefish, and should that process really be called “evolution”? This transformation fascinates biologists. Picture the scene—a normal-looking fish lays normal-looking eggs, but its hatchlings look like something from science fiction. Thin, pale-pink skin covers not just their bodies but their shrunken eye sockets as well.
 
MIT biology professor Susan Lindquist helped test the role a protein called “HSP90” plays in Mexican tetra (also known as blind cavefish) embryos.1 She has been studying the protein’s dramatic effects in plant, yeast, and fruit fly development, giving her a hunch that it might be working in fish, too.

Publishing in the journal Science, the team found that environmental cues somehow communicate to HSP90 in developing fish and that the protein does indeed control genetic variation for the size of tetra eyes and their sockets.1

The researchers ran two experiments. In one, they raised tetra with a chemical in the water that suppresses HSP90 activity. In another, they raised tetra in water with low-conductivity, mimicking that of cave water. Both tests induced essentially the same variations—a wider range in eye dimensions, even from parents with normal, average-size eyes. Therefore, it looks like the developing fish detect water conductivity, which inhibits HSP90, while still in their eggs.1 This appears to be one of the interrelated internal mechanisms that helps generate blind cavefish traits.

The study authors wrote of their results, “This strongly suggests an involvement of HSP90 in cavefish evolution and provides an actual case in nature for Waddington’s classic theory of the role of canalization in evolution.” They stated that “changes in HSP90 function can lead to changes in phenotype.”1,2

However, using the term “evolution” might prove as slippery as a cavefish. Textbook descriptions of evolution detail endless morphing between creature kinds through natural selection of mutants. But the sightless Mexican tetra exhibits development of helpful, cave-specific traits—not from harmful mutations but through genetic variability buffered by HSP90. For example, they acquire heightened, non-visual, sensory capabilities like those that detect motion, chemicals, and conductivity—and their lack of sight aids these capabilities. Plus, multiple subpopulations of the same fish kind have generated exactly the same cave-specific features in different caves at different times, and sighted and blind varieties have even interbred.3

Since the changes in these fish probably do not occur by natural selection of mutants, does  attributing them to “evolution” help explain the real, underlying biology? Mutations do not cause all changes in living things, so lumping both mutational and non-mutational causes together under one category (evolution) can be misleading. Instead, these observations align with design and built-in adaptability, not slow and gradual evolution.
 
Researchers wave the flag of evolution over all this cavefish biology, but the design of HSP90 actually makes the changes in several creatures through its “delicate balance of protein folding,” according to a press release from the Whitehead Institute for Biomedical Research.4 By showing that specific biochemical mechanisms—like variable amounts of HSP90—generate trait variations inside developing fish, these Science results fall right in line with the idea that a great Creator crafted high-tech genetic programming.

References

  1. Rohner, N. et al., 2013. Cryptic Variation in Morphological Evolution: HSP90 as a Capacitor for Loss of Eyes in Cavefish. Science. 342 (6164): 1372-1375.
  2. The quote refers to canalization, an idea that Conrad Waddington—a 20th-century British geneticist, embryologist, paleontologist, and Marxist philosopher—published in 1942. The Science authors summarized his ideas, writing, “Waddington proposed that developmental processes are quite robust and produce the same phenotype [physical trait] regardless of minor genotypic [genetic] variation, a phenomenon he termed ‘canalization.’ In such conditions, cryptic [hidden for generations] variation can accumulate and can be maintained without consequence.” (See reference 1.) Robust processes like these that anticipate and work around obstacles do not naturally occur.
  3. See references in Thomas, B. Evolution Made Cavefish Go Blind? Creation Science Update. Posted on icr.org February 7, 2012, accessed December 27, 2013.
  4. Fearer, M. Rapid Evolution of Novel Forms: Environmental Change Triggers Inborn Capacity for Adaptation. Whitehead Institute for Biomedical Research. Posted on wi.mit.edu December 12, 2013, accessed December 23, 2013.

Image credit: William Jeffery/MBL Woods Hole

* Mr. Thomas is Science Writer at the Institute for Creation Research.

Article posted on January 8, 2013.

The Latest
NEWS
Embarrassment Continues over Evolutionary Blunder about “Junk...
Recent research from the Okinawa Institute of Science and Technology Graduate University (OIST) continues to highlight how evolutionary theory influenced...

NEWS
God’s Plan Is Best: Salmon Need Saltwater Acclimation
Once again, results are better when aquaculture imitates the natural life cycle of Atlantic salmon.1,2 In other words, the closer fish farmers...

NEWS
Inside August 2020 Acts & Facts
Have you heard about ICR’s new President and Chief Operating Officer, Dr. Randy Guliuzza? What can we learn from an old prayer? Is creation evidence...

NEWS
After 30 Years, Red Kites Soar in British Skies
Good news is always welcome. So, it’s good to learn of another conservation comeback. This time it’s the red kite happily soaring in Great...

CREATION PODCAST
Meet Dr. G
Hear the history and heart of ICR’s newly appointed President and Chief Operating Officer, Dr. Randy Guliuzza. He has served as ICR’s National...

ACTS & FACTS
'Doing Business' in Good Times and Bad
No doubt many of you, like me, have been earnestly looking for the return of the Lord Jesus Christ. He called all believers to be godly “salt”...

APOLOGETICS
Sentinels Are Needed in Perilous Times
Watch out! Dangers lurk everywhere—these are surely perilous times.1 One of the apologetics-exhorting themes in Jude’s epistle...

ACTS & FACTS
Why Don't Raindrops Bomb Butterfly Wings?
Okay, I admit most folks have probably not thought to ask this creation question. But a bigger question gets answered when we examine the fantastic...

ACTS & FACTS
Believe Anyway
by Scott Arledge and Brian Thomas, Ph.D. Some within the creation community make the claim that they would believe God’s Word about the age...

DISCOVERY CENTER
The ICR Discovery Center for Science & Earth History Updates*
Plan your trip at ICRdiscoverycenter.org, where you’ll find ticket information, discounted rates for nearby hotels, and links to other...