血氧系统多样性 z-bo 2020-10-22 381

　　The survival, reproduction, and distribution of organisms are more or less affected by environmental oxygen. The normal aerobic metabolism of organisms depends on maintaining a balance between the demand (metabolism) and supply (storage and delivery) of oxygen. The realization of this balanced relationship mainly depends on the specific blood oxygen delivery system in the organism. The diversification of the blood oxygen system not only reflects the physiological diversity of species, but also reflects the adaptability of species to the environment. In the history of evolution, doubling the genome is an important contributor to the innovation of biological phenotypes. Numerous studies have revealed that the two ancient genome-wide doubling events that occurred in the early stages of vertebrate evolution have promoted the diversification of biological phenotypes, and thus promoted the adaptive evolutionary process of organisms. However, little is known about the significance and effects of recent genome doubling events, especially from the molecular genetic level that reflects the changes in the adaptability of species to environmental oxygen during evolution.

　　In order to explore the recent contribution of genome doubling to fish’s oxygen adaptability, researchers from the Laboratory of Ichthyology and Biogeography, Institute of Hydrobiology, Chinese Academy of Sciences, conducted research on the composition and expression patterns of representative hemoglobin genes in carps. A detailed investigation. Research papers Recent genome duplications facilitate the phenotypic diversity of Hb repertoire in the Cyprinidae are published online in the journal Science China Life Sciences.

　　There are many species of carps, and their morphological and physiological characteristics are quite different among species. It has been confirmed that recent genome doubling events occurred in multiple taxa of carps. The researchers collected genome and transcriptome data of representative diploid and polyploid species in carps. Through the re-annotation, collinearity analysis, evolutionary analysis, and comparative analysis of molecular conservation of the hemoglobin gene, the researchers once again confirmed that the recent genome doubling event occurred in polyploid species, and also found that hemoglobin gene in diploid species More conservative evolution has occurred; for polyploid species, recent doubling of the genome has promoted the evolution of the phenotype of the hemoglobin gene. Researchers believe that these complex patterns are related to the chromosome reorganization and the deletion of gene fragments after genome doubling. The incident is related.

　　In order to further study the expression of the hemoglobin gene, the researchers integrated the results obtained with the gene expression data, and the results showed that the expression of the hemoglobin gene has developmental stage regulation characteristics: the hemoglobin gene expressed in the early developmental stage of the diploid group is mainly located in " The 3'end of the MN" cluster, and the overall arrangement of genes alternates between hbα and hbβ genes and appears in the form of "tail-to-head", while the expressed genes in the later stages of development are basically in the opposite pattern; for polyploid In terms of species, these characteristics are no longer obvious, especially in polyploid species that repetitive evolutionary changes in gene expression have occurred. Researchers believe that for polyploid species that have experienced recent genome doublings, there will be a predictable sharp increase in the number of genes, but the results also show non-functionalization (pseudogenes, deletions, etc.) after gene doubling. This further leads to the complexity of gene evolution, and may promote changes in gene function and expression patterns, thereby providing a basis for species to better adapt to the environment.

　　Combining the results of studies on diploid and polyploid species that have been studied, the researchers speculate that the expression of more hemoglobin genes in polyploid species at different developmental stages not only reflects the physiological changes during their individual development , It also reflects its strong adaptability to the external oxygen environment from the side.