In this study, we developed 11 microsatellite markers specific to A. crataegi using NGS to investigate the genetic relationships of A. crataegi populations from South Korea to circumferential Asian countries (China, Russia, Mongolia, and Japan). Further, two mitochondrial DNA (mtDNA) gene segments (COI and CytB) were sequenced from the samples. The population- and individual-based Principal Coordinates and STRUCTURE analyses collectively suggested that the South Korean population of A. crataegi is most differentiated from the Japanese population, whereas it was closer to Mongolian and Chinese populations. These results collectively suggest that northern populations, in particular, Mongolian populations can be considered as the most genetically compatible one as donee population, when the reintroduction program is launched. †These authors contributed equally to this paper.

The black-veined white, Aporia crataegi (Lepidoptera: Pieridae), which is distributed mainly in Eastern Asia is presumed to be extinct in South Korea, only with some numbers of dried specimens left, whereas the species is found casually in circumferential countries. One of the common conservation practices for such species is to launch introduction program, but prior population genetic analysis between donor and donee populations might be essential for long-term conservation. In this study, we developed 11 microsatellite markers specific to A. crataegi using Illumina paired-end sequencing to investigate the genetic relationships of A. crataegi populations from South Korea and circumferential Asian countries (China, Russia, Mongolia, and Japan). Further, two mitochondrial DNA (mtDNA) gene segments (COI and CytB) were sequenced from the samples. The population- and individual-based Principal Coordinates and STRUCTURE analyses collectively suggested that the South Korean population of A. crataegi is most differentiated from the Japanese population, whereas it was closer to Mongolian and Chinese populations. The STRUCTURE analysis based on two concatenated mtDNA gene sequences also supported different genetic composition of Japanese population from the remaining populations including that of South Korea and rather similar genetic composition between the populations of South Korea and Mongolia. These results collectively suggest that northern populations, in particular, Mongolian populations can be considered as the most genetically compatible one as doner population, when reintroduction program is launched.

The black-veined white, Aporia crataegi (Lepidoptera: Papilionoidea), is nearly extinct in South Korea, although substantial numbers of dried specimens are available. One of the common practices for such species is to launch re-introduction program after proper amount of genetic information are analyzed from donor and donee populations. In this study, we sequenced complete mitochondrial genome (mitogenome) of A. crataegi to design species-specific primers for subsequent population works and to further understand the mitogenome evolution in lepodiopteran Papilionoidea. The 15,140-bp long A. crataegi mitogenome that has typical sets of 37 genes is smallest among true butterfly species with overall slightly smaller size in genes and regions throughout the genome. Arrangement of the genome is identical to those of other lepidopteran mitogenomes, in which tRNA cluster located between the A+T-rich region and ND2 gene is translocated into tRNAMet, tRNAIle, and tRNAGln from ancestral arrangement, tRNAIle, and tRNAGln, tRNAMet. The A/T content of the genome at 81.3% is the highest in Pieridae, but lower than that of lycaenid species (81.7% ~ 82.7%) The high A/T content in the genome is also reflected in codon usage, accounting for 41.69% of A/T-composed codons (TTA, ATT, TTT, and ATA). Unlikely the diversified or modified usage of anticodon for tRNASer(AGN) the species of Pieridae including A. crataegi all unanimously have GCT that has been hypothesized as ancestral for Lepidoptera. A total of 111 bp of non-coding sequences are dispersed in 13 regions, ranging in size from 1–49 bp. Among them relatively longer ones (≥ 16 bp) all have relatively higher sequence identity to other regions of the genome, suggesting partial duplication of the sequences during A. crataegi evolution. As has been reported in some species of Lepidoptera, the A. crataegi A+T-region also has typically found conserved sequences (e.g., poly-T stretch, ATAGA motif, ATTTA element, microsatellite-like A/T sequence, and poly-A stretch) and one tRNA-like sequence, and this feature was commonly found in true butterfly species.