Assessment of genetic diversity among four orchids based on ddRAD sequencing data for conservation purposes.

Genetic diversity was assessed in the four orchid species using NGS based ddRAD sequencing data. The assembled nucleotide sequences (fastq) were deposited in the SRA archive of NCBI Database with accession number (SRP063543 for , SRP065790 for SRP072201 for and SRP072378 for ). Total base pair read was 1.1 Mbp in case of sp., 553.3 Kbp for sp., 1.6 Gbp for , and 1.4 Gbp for . Average GC% was 43.9 in , 43.7% in , 41.2% in and 42.3% in . Four partial gene sequences were used in DnaSP5 program for nucleotide diversity and phylogenetic relationship determination ( gene of gene of , gene of and gene of ). Nucleotide diversity (per site) Pi (π) was 0.10560 in 0.03586 in 0.01364 in and 0.011344 in . Neutrality test statistics showed the negative value in all the four orchid species (Tajima's D value -2.17959 in , -2.01655 in -2.12362 in and -1.54222 in ) indicating the purifying selection. Result for these gene sequences (K and 2 and D) indicate that they were not evolved neutrally, but signifying that selection might have played a role in evolution of these genes in these four groups of orchids. Phylogenetic relationship was analyzed by reconstructing dendrogram based on the and gene sequences using maximum likelihood method in MEGA6 program.