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Han, G.-Z.

Publications and source records attributed to Han, G.-Z..

3 recordsLinked to original sources

Recombination shapes the diversification of the wtf meiotic drivers

Meiotic drivers are selfish genetic elements that distort fair segregation. The wtf genes are poison-antidote meiotic drivers that are experiencing rapid diversification in fission yeasts. However, gene duplication alone is insufficient to drive the diversification of wtf genes, given the poison encoded by a newly duplicated wtf gene can be detoxified by the antidote encoded by the original wtf gene. Here, we analyze the evolution of wtf genes across 21 strains of Schizosaccharomyces pombe. Knocking out each of 25 wtf genes in S. pombe strain 972h-separately does not attenuate the yeast growth, indicating that the wtf genes might be largely neutral to their carriers in asexual life cycle. Interestingly, wtf genes underwent recurrent and intricate recombination. As proof-of-principle, we generate a novel meiotic driver through artificial recombination between wtf drivers, and its encoded poison cannot be detoxified by the antidotes encoded by their parental wtf genes but can be detoxified by its own antidote. Therefore, we propose that recombination can generate new meiotic drivers and thus shape the diversification of the wtf drivers.

evolutionary biology↗

Strong and consistent associations of waterbird community composition with HPAI H5 occurrence in European wild birds

Since 2014, highly pathogenic avian influenza (HPAI) H5 viruses of clade 2.3.4.4 have been dominating the outbreaks across Europe, causing massive deaths among poultry and wild birds. However, the factors shaping its broad-scale outbreak patterns remain unclear. With extensive waterbird survey datasets of about 7,000 sites across Europe, we here demonstrated that H5N8 occurrence in wild birds in the 2016/17 and 2020/21 epidemics as well as H5N1 occurrence in 2005/06 epidemic were strongly associated with very similar waterbird community attributes, pointing to the possibility of similar interspecific transmission processes between different epidemics. A simple extrapolation of the model constructed from the 2016/17 epidemic can well predict the H5N8 pattern in wild birds in 2020/21 epidemic. We also found a dilution effect of phylogenetic diversity that was always negatively correlated with H5 occurrence in wild birds. In contrast, H5N8 occurrence in poultry was subject to different risk factors between the two epidemics. In general, waterbird community composition play a much more important role in determining the spatial pattern of H5N8 in wild birds than in poultry. Our work contributes to reveal the factors driving H5N8 patterns, and highlights the value of waterbird community factors in future HPAI surveillance and prediction.

ecology↗

Hidden diversity and macroevolutionary mode of Caulimoviridae uncovered by euphyllophyte paleoviruses

Few viruses have been documented in plants outside angiosperms. Endogenous viral elements (paleoviruses) provide molecular fossils for studying the deep history and macroevolution of viruses. Endogenous plant pararetroviruses (EPRVs) are widespread across angiosperms, but little is known about EPRVs in earlier branching plants. Here we use a large-scale phylogenomic approach to investigate the diversity and macroevolution of plant pararetroviruses (formally known as Caulimoviridae). We uncover an unprecedented and unappreciated diversity of EPRVs in the genomes of gymnosperms and ferns. The known angiosperm viruses only constitute a minor part of the Caulimoviridae diversity. By characterizing the distribution of EPRVs, we show that no major euphyllophyte lineages escape the activity of Caulimoviridae, raising the possibility that many exogenous Caulimoviridae remain to be discovered in euphyllophytes. We find that the copy numbers of EPRVs are generally high, suggesting that EPRVs define a unique group of repetitive elements and represent major components of euphyllophyte genomes. Phylogenetic analyses reveal an ancient monilophyte origin of Caulimoviridae and at least three independent origins of Caulimoviridae in angiosperms by cross-division transmissions. Our findings uncover the remarkable diversity of Caulimoviridae and have important implications in understanding the origin and macroevolution of plant pararetroviruses.

evolutionary biology↗