Blasio Francesco, Prieto Pilar, Pradillo Mónica, Naranjo Tomás
Departamento de Genética, Fisiología y Microbiología, Facultad de Biología, Universidad Complutense de Madrid, 28040 Madrid, Spain.
Plant Breeding Department, Institute for Sustainable Agriculture, Agencia Estatal Consejo Superior de Investigaciones Científicas (CSIC), Alameda del Obispo s/n, Apartado 4048, 14080 Cordova, Spain.
Plants (Basel). 2022 Jan 3;11(1):125. doi: 10.3390/plants11010125.
Hybridization and polyploidy have been considered as significant evolutionary forces in adaptation and speciation, especially among plants. Interspecific gene flow generates novel genetic variants adaptable to different environments, but it is also a gene introgression mechanism in crops to increase their agronomical yield. An estimate of 9% of interspecific hybridization has been reported although the frequency varies among taxa. Homoploid hybrid speciation is rare compared to allopolyploidy. Chromosome doubling after hybridization is the result of cellular defects produced mainly during meiosis. Unreduced gametes, which are formed at an average frequency of 2.52% across species, are the result of altered spindle organization or orientation, disturbed kinetochore functioning, abnormal cytokinesis, or loss of any meiotic division. Meiotic changes and their genetic basis, leading to the cytological diploidization of allopolyploids, are just beginning to be understood especially in wheat. However, the nature and mode of action of homoeologous recombination suppressor genes are poorly understood in other allopolyploids. The merger of two independent genomes causes a deep modification of their architecture, gene expression, and molecular interactions leading to the phenotype. We provide an overview of genomic changes and transcriptomic modifications that particularly occur at the early stages of allopolyploid formation.
杂交和多倍体被认为是适应和物种形成过程中的重要进化力量，在植物中尤为如此。种间基因流产生适应不同环境的新遗传变异，但它也是作物中增加农艺产量的基因渐渗机制。尽管不同分类群的频率有所不同，但据报道种间杂交的比例约为9%。与异源多倍体相比，同源多倍体杂交物种形成较为罕见。杂交后染色体加倍是主要在减数分裂过程中产生的细胞缺陷的结果。未减数配子是纺锤体组织或方向改变、动粒功能紊乱、异常胞质分裂或任何减数分裂缺失的结果，其在物种间形成的平均频率为2.52%。减数分裂变化及其遗传基础导致异源多倍体的细胞学二倍体化，尤其是在小麦中才刚刚开始被理解。然而，在其他异源多倍体中，同源重组抑制基因的性质和作用模式却知之甚少。两个独立基因组的合并会导致它们的结构、基因表达和分子相互作用发生深刻改变，从而产生表型。我们概述了异源多倍体形成早期特别发生的基因组变化和转录组修饰。
