Since the beginning of time, our appearance, behaviors, and our very survival have all been predetermined by the genetics coded in our DNA. These genetics not only embed
information that shapes the unique characteristics of living organisms but also insights about the origins of life on Earth.
The DNA shared by diverse organisms provide vital evidence for the common origin of life on Earth. However, countless genes that were not contributing to organisms' survival “faded into obscurity”. In this article, we will explore the factors contributing to losing genes, the methods scientists employ to search for them, and their impact on existing organisms.
Use It or Lose It
Genes, the building blocks of life, can “fade away” through natural selection. This mechanism of evolution compels nature to engage in a perpetual battle for the survival of the fittest, where advantageous traits grant organisms a longer life. This constant adaptation to changes in the natural environment can lead to the elimination and extinction of genes over time, shaping the very essence of organisms.
How do we find extinct genes?
When searching for lost genes in an organism, scientists use a combination of experimental and computational methods. The five standard methodologies:
Genome Sequencing - obtains and analyzes the organism's genomic sequence to identify genes and deduce lost ones.
Comparative Genomics - comparing the organism's genome with related organisms to infer the presence of lost genes by finding regions of similarity or conservation.
Transcriptomics - analyzes the organism's gene expression patterns by studying RNA transcripts, and comparing them with related organisms to identify potentially lost genes not actively transcribed.
Functional Assays - conducts experiments to test the function of specific genes or gene regions, reintroducing candidate genes or assessing the impact of gene knockouts to determine if particular genes are lost or have undergone functional changes.
Impacts of Lost Genes
While losing genes may sound concerning or unfavorable at first, there is no inherent disadvantage to the process of gene loss. It is a natural and necessary phenomenon that living organisms must undergo to adapt and survive in ever-changing environments. It allows organisms to specialize and optimize their genetic material, making their genomes more efficient and reducing the risk of errors. This can even lead to the development of new functionalities and adaptations. Thus, gene loss is an essential mechanism contributing to living organisms' ongoing evolution and resilience.
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Works Cited
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Castillo-Ramirez, S. and J. Feil, E. (2014). Chapter 18 - Towards a Synthesis of Population Genomics and Epidemiology: Next-Generation Sequencing of Bacterial Pathogens. Molecular Medical Microbiology (Second Edition), 1(2), pp.337–345. doi:https://doi.org/10.1016/B978-0-12-397169-2.00018-4.
Figeys, D. and Rossetto, F. (2002). Finding the ‘lost’ genes. Trends Biotechnology, 20(4), p.144. doi:https://doi.org/10.1016/S0167-7799(02)01947-9.
Hathaway, B. (2023). ‘Deletions’ from the human genome may be what made us human. [online] YaleNews. Available at: https://news.yale.edu/2023/04/27/deletions-human-genome-may-be-what-made-us-human [Accessed 11 May 2024].
National Geographic Society (2022). Natural Selection | National Geographic Society. [online] National Geographic. Available at: https://education.nationalgeographic.org/resource/natural-selection/ [Accessed 11 May 2024].
PBS Eons (2021). The Genes We Lost Along the Way. [online] Youtube. Available at: https://www.youtube.com/watch?v=6Vc2bM2aQsw&ab_channel=PBSEons [Accessed 11 May 2024].
Wang, X., Grus, W.E. and Zhang, J. (2006). Gene Losses during Human Origins. PLoS Biology, 4(3), p.e52. doi:https://doi.org/10.1371/journal.pbio.0040052.
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