Birzu Gabriel, Muralidharan Harihara Subrahmaniam, Goudeau Danielle, Malmstrom Rex R, Fisher Daniel S, Bhaya Devaki
Department of Applied Physics, Stanford University, Stanford, CA 94305, USA.
Department of Computer Science, University of Maryland, College Park, MD 20742, USA.
bioRxiv. 2023 Jun 7:2023.06.06.543983. doi: 10.1101/2023.06.06.543983.
Bacterial species often undergo rampant recombination yet maintain cohesive genomic identity. Ecological differences can generate recombination barriers between species and sustain genomic clusters in the short term. But can these forces prevent genomic mixing during long-term coevolution? Cyanobacteria in Yellowstone hot springs comprise several diverse species that have coevolved for hundreds of thousands of years, providing a rare natural experiment. By analyzing more than 300 single-cell genomes, we show that despite each species forming a distinct genomic cluster, much of the diversity within species is the result of hybridization driven by selection, which has mixed their ancestral genotypes. This widespread mixing is contrary to the prevailing view that ecological barriers can maintain cohesive bacterial species and highlights the importance of hybridization as a source of genomic diversity.
细菌物种常常经历大量的重组，但仍保持着连贯的基因组特性。生态差异能够在物种之间产生重组障碍，并在短期内维持基因组簇。但是，这些力量能否在长期共同进化过程中阻止基因组混合呢？黄石国家公园温泉中的蓝细菌包含几个已经共同进化了数十万年的不同物种，这提供了一个罕见的自然实验。通过分析300多个单细胞基因组，我们发现，尽管每个物种都形成了一个独特的基因组簇，但物种内部的许多多样性是由选择驱动的杂交结果，这种杂交混合了它们的祖先基因型。这种广泛的混合与生态障碍能够维持连贯的细菌物种这一普遍观点相悖，并突出了杂交作为基因组多样性来源的重要性。
