Comparative plastid genomics of Mazaceae: focusing on a new recognized genus, Puchiumazus

Ten Plastomes of Crassula (Crassulaceae) and Phylogenetic Implications

“…Generally, the dN/dS ratios of genes could reflect the extent of selection pressures during evolution [ 22 ]. Here, the dN/dS values of plastid PCGs ranged from 0 to 0.5891 within Crassulaceae, indicating all plastid genes were under purifying selection.…”

“…Similarly, high dN/dS ratios of these two genes were also observed in other families, such as Asteraceae Bercht. & J.Presl [ 38 ], Mazaceae Reveal [ 22 ], and Musaceae Juss. [ 13 ].…”

“…In angiosperms, the plastid genome (plastome) generally exhibits a conserved quadripartite circular structure with a size of 120–170 kb, comprising two single copy regions (larger and small regions, namely LSC and SSC, respectively) and two inverted repeat regions (IRs) [ 14 , 15 , 16 ]. Owing to the low level of recombination, uniparental inheritance, and without interference from paralogs, plastome has been extensively utilized as a super-barcode for plant species identification and evolutionary studies [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. Due to the rapid development and widespread application of high-throughput sequencing technologies (such as Illumina, PacBio, and Nanopore sequencing technologies), an increasing number of complete Crassulaceae plastomes (more than 70 sequences) have been deposited in public databases.…”

“…The dN/dS values in different genes are variable, which might be influenced by many factors, such as protein function, population size, generation time, and DNA-repair efficiency [ 36 , 37 ]. The dN/dS values of plastid genes have been measured in many plant lineages, and most values were lower than 1, indicating plastid genes were mainly under the purifying selection [ 13 , 22 , 38 , 39 , 40 ]. Currently, the detailed rates and patterns of plastid genes were largely unknow in Crassulaceae.…”