Chromosomal evolution and polyploidy dynamics in tribe Andropogoneae (Poaceae: Panicoideae): insights from phylogenomic reconstruction

Summary The dissertation explored the chromosomal evolution of 230 species in the Andropogoneae tribe (Poaceae), which includes 1.224 species, using a detailed search of literature and databases. The phylogenetic analysis was based on complete plastome sequencing, and ancestral reconstruction utilized Bayesian inference and character optimization. Results indicated high diversity, with 46 variations in chromosome number (2n), ranging from 8 to 140, and 30% of species exhibiting polyploidy. This suggests multiple chromosomal alteration events occurred during the tribe’s evolution. The chromosome number 2n = 20 was identified as the ancestral state for most internal nodes of the tree and confirmed as predominant in the Andropogoninae subtribe. However, more recently divergent taxa displayed higher chromosome numbers. The research concludes that chromosomal variation is dynamic and complex. It emphasizes the importance of obtaining more chromosomal data to fill knowledge gaps and achieve a more complete understanding of the diversity and evolutionary mechanisms shaping the Andropogoneae tribe. Competing Interest Statement The authors have declared no competing interest.