Document Type : Commentary
Authors
- Seyed Ali Reza Mortazavi 1
- Ilham Said-Salman 2, 3
- Sami El Khatib 4, 5
- Parmis Taghizadeh 6
- Seyed Mohammad Javad Mortazavi 7, 8
- Lembit Sihver 9, 10, 11
1 MVLS College, The University of Glasgow, Glasgow, Scotland, UK
2 Department of Biological and Chemical Sciences, School of Arts & Sciences, Lebanese International University, Beirut, Lebanon
3 International University of Beirut, Beirut, Lebanon
4 Department of Biomedical Sciences, School of Arts and Sciences, Lebanese International University, Beirut, Lebanon
5 Center for Applied Mathematics and Bioinformatics (CAMB) at Gulf University for Science and Technology, Kuwait City, Kuwait
6 School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
7 Ionizing and Non-Ionizing Radiation Protection Research Center (INIRPRC), Shiraz University of Medical Sciences, Shiraz, Iran
8 Department of Medical Physics and Engineering, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
9 Department of Radiation Physics, Technische Universität Wien, Atominstitut, 1040 Vienna, Austria
10 Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, ON, CanadaUSA
11 Department of Physics, East Carolina University, Greenville, NC
Abstract
Natural selection, a cornerstone of evolutionary biology, shapes the adaptations organisms develop to survive environmental pressures. This paper explores how natural selection drives biological adaptations to radiation exposure. We examine the genetic mechanisms at play, exemplified by the enhanced DNA repair capabilities observed in bacteria like Escherichia coli (E. coli) following exposure to radiation. We then investigate adaptations in humans residing in high-background radiation areas, highlighting potential genetic variations for radiation resistance. Finally, the contemporary relevance of natural selection is discussed, emphasizing its role in the emergence of antibiotic-resistant bacteria and the need for sustainable medical practices. By studying these adaptations, we gain a deeper understanding of evolution and its implications for medicine, conservation, and our overall understanding of life.
Highlights
Seyed Mohammad Javad Mortazavi (Google Scholar)
Lembit Sihver (Google Scholar)
Keywords
Introduction
Living organisms constantly face environmental pressures that challenge their survival. Darwin’s theory of natural selection provides a framework for understanding the evolution of life forms under various environmental pressures. When exposed to radiation, living organisms with genetic variations that offer some level of protection will have a higher chance of survival and reproduction. Over generations, these beneficial adaptations become more prevalent in the population. This paper examines how natural selection drives biological adaptations to radiation, offering insights into the genetic and physiological mechanisms that organisms employ to thrive in high-radiation environments.
Natural Selection and Genetic Adaptations
The concept of natural selection is exemplified in the genetic adaptations that organisms develop in response to environmental challenges. For instance, elephants have a lower incidence of cancer despite their large size and extended lifespans. This is attributed to genes like P53, which helps suppress tumor formation, illustrating how genetic traits can evolve to counteract potential vulnerabilities [ 1 ].
Radiation Resistance in Microorganisms
Rapid reproduction rates in microorganisms such as bacteria allow us to observe natural selection in real-time. For example, the work of Evelyn Witkin [ 2 ] showed that Escherichia coli could develop resistance to UV radiation through genetic mutations, a direct observation of Darwin’s principles in action. Subsequent studies have confirmed that repeated exposure to high-dose radiation selects for variants with enhanced DNA repair capabilities, not only in E. coli [ 3 ], but also in organisms like Salmonella enterica and Bacillus pumilus [ 4 , 5 ].
Human Adaptations to Environmental Radiation
In humans, adaptations occur over much longer periods due to slower reproductive rates and the complex interplay of genetics and environment. In regions with high background radiation, such as Ramsar, Iran, residents exhibit genetic adaptations that might reflect an evolved resistance to radiation-induced health effects [ 6 ]. Human adaptations to environmental radiation also include changes in skin pigmentation in response to UV radiation levels and potentially cancer-resistance mechanisms, showcasing natural selection’s role in human evolution.
Contemporary Implications of Natural Selection
The principle of natural selection remains relevant today, influencing modern medicine and public health. The widespread use of antibiotics and antivirals has led to the emergence of resistant strains of bacteria and viruses, a contemporary example of the “survival of the fittest”. This underscores the need for sustainable medical practices that consider long-term evolutionary impacts.
Conclusion
Darwin’s theory of natural selection continues to provide valuable insights into how species adapt to environmental stressors, including radiation. By studying these processes, we can better understand the dynamics of evolution and improve strategies to manage biological challenges in medicine and conservation.
Authors’ Contribution
SAR. Mortazavi, SMJ. Mortazavi, and L. Sihver conceived of the presented idea. SAR. Mortazavi, and L. Sihver developed the main theory. SMJ. Mortazavi modified the theoretical framework. All authors provided critical feedback and helped shape the research, and manuscript.
Conflict of Interest
SMJ. Mortazavi and L. Sihver, as the Editorial Board Members, were not involved in the peer-review and decision-making processes for this manuscript.
References
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