Core Insights - A recent study from Nanjing Agricultural University has been highlighted in Cell Press, focusing on the evolution of protein domains and their combinations, providing insights into the origin and diversification of land plants [2][4]. Summary by Sections - The research identifies protein domains as the fundamental units determining function at the protein level, originating from ancient single-exon genes. These domains can form standalone proteins or combine with others to create chimeric proteins, allowing for the evolution of diverse protein functions through domain rearrangement [6]. - The study analyzed 446 genomes covering all major plant lineages, revealing that the number of identified domains and domain combinations in land plants exceeds that found in algae. The early evolution of land plants involved the acquisition of novel "core" protein domains, enriching the genomic toolkit necessary for transitioning from unicellular to multicellular organisms and adapting to terrestrial life [6][8]. - After conquering land, the number of ancestral core domains in land plants has continued to decrease, while the number of acquired non-core domains has increased. This, along with enhanced domain rearrangement activities, has led to a greater diversity of proteins [6]. - The research team suggests that the loss of existing genetic elements (core domains) may not always be detrimental, as it could reduce evolutionary constraints, paving the way for biological innovation and adaptation to changing environments [6][8].