Nat Ecol. Evol. Break the stereotype!

Recently, the journal Nature Ecology & Evolution published online a research paper titled "Prochlorococcus have low global mutation rate and small effective population size" from Professor Zhang Yao of Xiamen University and Professor Luo Haiwei of the Chinese University of Hong Kong.
In the process of evolution, the well-known "natural selection" is not as important as traditional cognition, and the "genetic drift" that has been neglected plays a key role
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As early as hundreds of millions of years ago, Prochlorococcus lived on the earth.
They brought a prosperous era of "Great Oxidation" to the original "oxygen-deficient" earth and provided important conditions for the rapid development of subsequent biological evolution
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Today, as the most important primary producer in the ocean, Prochlorococcus fixes about 4 billion tons of carbon annually through photosynthesis, and is an important contributor to the "ocean carbon sink"
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As an extremely important organism in the evolution of the earth and the most important primary producer in today's oceans, Prochlorococcus has irreplaceable evolutionary and ecological significance
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Prochlorococcus is abundant and widely distributed
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And "genetic drift" is a process in which the gene pool of a population changes randomly between generations, usually especially in small groups
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For many years, the academic community has always assumed that the effective population of Prochlorococcus is very large, and then believed that natural selection was extremely effective in the evolutionary adaptation of Prochlorococcus, ignoring the role of genetic drift
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△ Prochlorococcus This research is the first time to participate in the competition through continuous debugging experiments, establishing a stable monoclonal laboratory culture program of Prochlorococcus, and achieving stable passage
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The study found that the rate of gene mutation of Prochlorococcus is very slow, which has subverted the knowledge of the academic community
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In addition, the study calculates that the effective population size of Prochlorococcus is only 1.
68 × 107, which is smaller than many typical marine free-living bacteria; further analysis found that although Prochlorococcus is widely distributed, different niches are affected by different metabolic characteristics.
Occupied by isolated populations
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But at the same time, various groups are isolated from each other, no gene exchange occurs, and the level of gene recombination within the group is low
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Therefore, the study proposes a "periodic selection" mechanism for enhancing genetic drift of Prochlorococcus, which provides a common genetic reduction phenomenon of dominant flora in oligotrophic sea areas, in addition to the traditional "oligotrophic environment adaptation" viewpoint, provides An innovative perspective and theory
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△ Paper with map: The relationship between the size of the nuclear organism genome (G), the rate of base substitution (μ), the rate of whole genome mutation (Up), and the effective population size (Ne) There are so many species in the world, they Not all are the best selected by natural selection, and some species may just be lucky to survive
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Although the role of 'natural selection' has been generally understood and believed by the public, we cannot ignore the role of 'genetic drift'
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A series of findings from this study broke the academic community's inherent cognition on the evolution of Prochlorococcus
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Chen Zhuoyu and Dr.
Wang Xiaojun of the Chinese University of Hong Kong are the co-first authors of the paper, and Professor Zhang Yao and Professor Luo Haiwei of the Chinese University of Hong Kong are the co-corresponding authors of the paper
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