Mitochondrial genome sequencing and phylogenetic analysis of Cynodon dactylon × Cynodon transvaalensis


Abstract: Cynodon dactylon × Cynodon transvaalensis is one of the most important turfgrasses. Sequencing the C. dactylon × C. transvaalensis mitochondrial genome can help us learn more about its genomic composition and allow further study of the population genetics, taxonomy, and evolutionary biology of Poaceae plants and other related species. Here the C. dactylon × C. transvaalensis mitochondrial genome was sequenced using Illumina HiSeq combined with PacBio sequencing technology, and the map of the mitochondrial genome was constructed after de novo assembly and annotation. The C. dactylon × C. transvaalensis mitochondrial genome has 366,612 bp and contains 53 genes, including 31 protein-coding genes, 3 rRNA genes, and 16 tRNA genes. The result of relative synonymous codon usage (RSCU) showed an A or U preference at the third position of the codons. Thirty-three chloroplast DNA fragments were found in C. dactylon × C. transvaalensis mitochondrial DNA, ranging from 72 to 3003 bp. Phylogenetic trees built based on the chloroplast genome were congruent with the plant taxonomy and NCBI taxonomy common tree, while the phylogenetic trees built based on 9 mitochondrial genes showed some differences from the common tree.

Keywords: Cynodon dactylon × Cynodon transvaalensis, mitochondrial genome, phylogenetics, repeat sequence, gene transfer

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