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Understanding genome evolution and biodiversity through host-pathogen interactions

30 Apr 2025

Professor Zhao Zhongying (right) and Dr Jeffrey Xie Dongying of the Department of Biology have identified the first gene linked to the hybrid lethality between the worms Caenorhabditis briggsae and C. nigoni. Professor Zhao Zhongying (right) and Dr Jeffrey Xie Dongying of the Department of Biology have identified the first gene linked to the hybrid lethality between the worms Caenorhabditis briggsae and C. nigoni.
Professor Zhao Zhongying (right) and Dr Jeffrey Xie Dongying of the Department of Biology have identified the first gene linked to the hybrid lethality between the worms Caenorhabditis briggsae and C. nigoni.

 

In the intricate world of biology, every gene and every cell play an essential role in composing the symphony of life. Professor Zhao Zhongying and Dr Jeffrey Xie Dongying from the Department of Biology have made a remarkable discovery that could change our understanding of how species survive in the face of disease, shedding light on the complex interactions between hosts and pathogens.

While hosts often develop antipathogen genes to counter or alleviate the threat, pathogens may evolve tactics to evade or suppress the defences of the immune system, driving fast genetic changes in the hosts over time. “The dynamic interactions between hosts and pathogens have a profound impact on genome evolution and biodiversity. Understanding these processes not only sheds light on fundamental biological mechanisms but also has implications for disease control and management,” says Professor Zhao.

In a study published in the Proceedings of the National Academy of Sciences, Professor Zhao and Dr Xie focused on the evolution of immune response genes. The findings provide clear evidence that gene duplication and the subsequent functional changes in response to environmental challenges, such as pathogen exposure, can create reproductive barriers between closely related species. This shows that small but fast genetic changes in the hosts can prevent different species from successfully interbreeding, a process which is referred to as genetic conflict. The study highlights that genetic changes in response to pathogen defence could result in speciation, an evolutionary process of how a new species is created.

Furthermore, the study confirms that the interactions between the host and pathogen are a persistent and ever-changing process, where each change significantly impacts the survival and reproduction of species. “The genetic conflicts arising from host-pathogen interactions not only influence the evolution of organisms, but also provide crucial insights into genetic diversity and the emergence of new species,” Professor Zhao says.

Nonetheless, the research journey was not without challenges. The study involved two species of worms, and the team faced difficulties in identifying specific genes responsible for the reproductive incompatibility between the two species, as these genes evolve quickly. To overcome these challenges, the team developed a customised gene-mapping method to conduct in-depth analyses on the related genomes while ensuring a vigorous experimental design.

This groundbreaking research underscores the complex relationships among genetics, evolution and ecology, illustrating how life swiftly adapts to environmental pressures like pathogens. It also represents a powerful melody in the biological world, with each note telling a story of survival and adaptation. As Professor Zhao expresses: “Understanding these adaptations reveals the profound interconnectedness of biological systems, where changes in one aspect can have cascading effects on the other aspects, including evolution of biodiversity. This reinforces the need for transdisciplinary approaches in biological research.” Exploring the dynamics between hosts and pathogens in various systems is essential for deepening our knowledge of immune diseases because every organism contributes to our understanding of the complex narrative of survival and adaptation on Earth.