Genomic Structure And Functional Evolution In Early Stage Of Eudicot Divergence

Eudicots account for 75% of living angiosperms and are the largest and most species-diverse of the four main groups of angiosperms(basal angiosperms,magnoliids,monocots and eudicots).Many typical core and basal eudicots have been sequenced,providing important genomic data to investigate the evolutionary characteristics of earlydiverging eudicots.Comparative genomics and phylogenetic analysis were conducted on several representative eudicots,and some advances were made in the evolution of structure and function of early-diverging eudicots.(1)Several polyploidization events occurred during the early divergence of eudicots were clarified.Using the grape genome as reference,a table of multi-genome of homologous genes related to polyploidy and species divergence was constructed to show the homology of chromosome fragments and genes.(2)The evolutionary rates of eudicots are obviously different by comparing the synonymous nucleotide substitution.By performing evolutionary rate correction,it is confirmed that the multiple polyploidization and species divergence events of eudicots occurred in a relatively short period.The degrees of gene retention and loss between subgenomes were compared and it is revealed that multiple polyploidy events of earlydiverging eudicots may be allo-polyploidies,which may shape the major eudicot clades.(3)By inferring the karyotype evolution of representative species of main eudicot clades,it is found that the chromosomes of tetracentron and boxwood are closer to the eudicot ancestral chromosome structure,which could be used as reference for the study of eudicot genome structure.(4)Polyploidy and tandem duplication play an important role in the expansion of(AG,SQUA,SEP,FLC,TM3)subfamily.Different subfamily members have similar domains,and different motifs at one end of the sequences may lead to different functions of subfamily.The research will provide an important genomic basis for study of genome structure and function evolution of important genes of eudicots.Figure 20;Table 6;Reference 71...