The alignments of chloroplast genome sequences and nuclear ribosomal DNA fragments of six oak species sampled in the hot-dry valley of the Jinsha River, southwestern China

Both chloroplast (cp) genome sequences and nuclear ribosomal (nr) DNA were assembled using GetOrganelle v.1.7.6.1 for 18 oak trees sampled in the Panzhihua Cycad National Nature Reserve, Sichuan Province, China. These trees belong to six oak species, including Quercus cocciferoides, Q. dolicholepis, Q. franchetii, Q. griffithii, Q. longispica, and Q. variabilis. We used PhyloSuite v.1.1.152 to extract coding sequences (CDSs), tRNA genes, rRNA genes, introns, and intergenic spacers (IGSs) of the 18 oak cp genomes. These sequences were aligned separately using MAFFT v.7.3.13 and manually adjusted with BioEdit v.7.2.5. Length variations in mononucleotide repeats were excluded and inversions were replaced with their reverse complements because of their tendency for homoplasy. Other indels were coded as binary characters according to the simple gap coding method using GapCoder. Separate assignments were concatenated according to their respective positions in the cp genome to obtain the alignments of LSC, SSC, IRb, and the whole cp genome.