Does Chernobyl Disprove Genetic Entropy?
A study on roundworms thriving in the
forbidden zone does not falsify the
genetic entropy effect of mutations
by Jerry Bergman, PhD
New research has concluded that roundworms have not suffered any major detectable genetic damage from long-term exposure to the 1986 accident at the Chernobyl nuclear plant in Ukraine (also known as Chornobyl). Does this research disprove, or at least counter, the creationists’ claims that mutations slowly build up in life, eventually causing genetic catastrophe, i.e., extinction?
If life can be protected from mutation genetic damage, it could exist for enormous periods of time and avoid genetic catastrophe. Also, the reverse side is, if life was strongly resistant to mutational changes, life could not evolve. Evolutionists propose that the source of genetic change that causes evolution is mutational damage which causes genetic change. If the genetic change improves survivability it will be passed onto its offspring. Eventually, the life forms with the mutant gene will dominate the population.
New York University researchers discovered that long-term exposure to the radiation produced by the explosion of the Chernobyl nuclear power plant has not damaged the genomes of the microscopic worms called nematodes living there today. This finding indicates that these worms are exceptionally resilient to mutational DNA damage.
[1] Because nematodes have simple genomes and rapid reproduction, they are very useful for understanding many basic biological phenomena. It was for this reason that they were selected for the New York University research.
The Research Design
The nematodes for analysis were collected from locations close to the Chernobyl explosion. The radiation level ranged from low levels that are close to that existing in New York City (negligibly radioactive) to high-radiation sites that equal that existing in outer space not protected by the Earth’s magnetic field. This level of radiation is very dangerous for humans. The genetic analysis of the genes obtained by sequencing the nematode’s genome concluded from comparing the genomes that the radiation exposure difference made no difference in the genetic changes. In short, DNA comparisons revealed the higher radiation did not cause any increase in mutations. This example illustrates the fact that sensitivity to radiation varies enormously among different life-forms.
The Tardigrade Design
One example of an organism that can survive in environments that are far more hostile to life than they could experience on Earth is the tardigrade design.[2] These most amazing life-forms are among the most resilient animals on Earth.[3] They are able to survive extreme conditions that would rapidly kill most all other known life-forms. Detailed study of their radiation resistance has confirmed that they are one of the most resistant life-forms known to scientists.[4] One tardigrade species that glows blue when exposed to ultraviolet light, uses the power of fluorescence as a shield to protect themselves from levels of UV radiation known to effectively kill other microorganisms, including bacteria and viruses.
The tardigrade can even withstand being zapped with X-rays that are 250 times more intense than that which would kill an average human. One group of tardigrades managed to survive for 30 days following an X-Ray dosage that kills bacteria and nematode worms in just a few minutes. In a follow-up study, Professor Eswarappa and his colleagues cranked the dose up to four kilojoules per square meter for a full hour. Fully 60 percent of the tardigrades survived for 30 days after this intense exposure.[5]
The Chernobyl Disaster Research
The Chernobyl Disaster cancer victims help us to understand why humans are very susceptible to radiation exposure. Of the 600 workers onsite, 134 suffered acute radiation sickness and 28 died within the first three months. Workers and the public were exposed to three main types of radionuclides: iodine-131, cesium-134, and cesium-137. When iodine-131 is released into the environment, it is taken up by the thyroid gland. However, I-131 rapidly decays into the non-radioactive form, iodine-127. Its half-life is short, only 8 days. The major portion of iodine in the body is concentrated in the thyroid gland and is used to manufacture the hormone thyroxine (T4) and tri-iodothyronine (T3). The numbers 3 and 4 refer to the number of iodine atoms in the hormone.
The high concentration of radioactive iodine in the thyroid gland is what caused an epidemic of thyroid cancer after the Chernobyl accident.[6] The total number of cases of thyroid cancer in the 1991–2015 period among those under age 18 years approached 20,000. An estimated 5,000 thyroid cancer cases were attributable to radioactive iodine (iodine-131) exposure to the children or adolescents at the time of the accident.[7] It would rarely cause cancer in other human organs because they do not concentrate this specific element. This is why there were no other increases in the rates of solid cancers, leukemia, and non-cancerous diseases caused by the radiation exposure.
In the case of nematodes, as they do not have a thyroid gland, they would not absorb iodine-131, and cesium is present in the soil only in trace amounts. Excessive amounts can have negative effects on health. Thus, nematodes would not actively absorb cesium metal. Nematodes do not have a respiratory system and obtain oxygen by diffusion through their semi-permeable membrane. Consequently, they would absorb only small amounts from their soil environment. Nematodes would not absorb significant amounts of cesium metal for another reason, which, compared to oxygen, is a large molecule. Cesium has atomic weight 132 compared to oxygen (16), so it is over 8 times as large.
Summary
The effect of radionuclides on life depends on many complex interrelated factors. Some animals, mostly the smaller comparatively simple organisms, are resistant to mutational damage. Conversely, most higher order animals, such as mammals, tend to be more affected by radiation than other animals. Consequently, the few exceptions do not negate the norm. Furthermore, I did not notice any claims that the mutations caused by the Chernobyl radiation produced any improvements in the genome of the nematodes. If some advantage was noted, it would likely have been mentioned.
References
[1]Tintor, Sophia C., et al. “Environmental radiation exposure at Chornobyl has not systematically affected the genomes or chemical mutagen tolerance phenotypes of local worms;” https://www.pnas.org/doi/abs/10.1073/pnas.2314793121, 30 May 2023.
[2] Catchpoole, David. “Tardigrades too tough for evolution.” Creation 40(1):27, January 2017.
[3] Sloan, David, Rafael Alves Batista, and Abraham Loeb. “The resilience of life to astrophysical events.” Scientific Reports 7(1):5419, 2017.
[4] Bittel, Jason. “Tardigrade protein helps human DNA withstand radiation.” Nature; |https://www.nature.com/articles/nature. 2016.20648, 2016.
[5] Harikumar, Suma. et al., Naturally occurring fluorescence protects the eutardigrade Paramacrobiotus sp. from ultraviolet radiation. Biology Letters 16(10):20200391, October. 2020
[6] “Health Effects of the Chernobyl Accident.” March 2022.
[7] United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Report titled “Health effects due to radiation from the Chernobyl accident and the UNSCEAR,” 2008; White Paper titled “Evaluation of data on thyroid cancer in regions affected by the Chernobyl accident,” 2018.
Dr. Jerry Bergman has taught biology, genetics, chemistry, biochemistry, anthropology, geology, and microbiology for over 40 years at several colleges and universities including Bowling Green State University, Medical College of Ohio where he was a research associate in experimental pathology, and The University of Toledo. He is a graduate of the Medical College of Ohio, Wayne State University in Detroit, the University of Toledo, and Bowling Green State University. He has over 1,900 publications in 14 languages and 40 books and monographs. His books and textbooks that include chapters that he authored are in over 1,800 college libraries in 27 countries. So far over 80,000 copies of the 60 books and monographs that he has authored or co-authored are in print. For more articles by Dr Bergman, see his Author Profile.