The rapid development of DNA sequencing technology in recent years has provided new tools for phylogenetic data acquisition. By using high-throughput DNA sequencing technology, molecular phylogenetic information can be obtained more quickly and economically. Here, we describe a complementary combination of two multiplex high-throughput DNA sequencing methods. One is multiplexed phylogenetic marker sequencing (MPM-seq), and the other is multiplexed inter-simple sequence repeat (ISSR) genotyping by sequencing (MIGseq), whose protocol is improved over that of the original one. Both MPM-seq and MIG-seq begin with multiplex polymerase chain reaction (PCR), each amplifying multiple phylogenetic markers and genome-wide ISSR regions, respectively.After another PCR using a second PCR primer set that is common in both methods, next-generation sequencing is used to simultaneously detect DNA sequences of multiple regions from multiple samples in each method. In this case study, we performed a molecular phylogenetic analysis of Japanese fir (Abies) and the closely related Abies species. MPM-seq revealed DNA sequences of three regions from chloroplast DNA and one nuclear internal transcribed spacer and created a partially informative phylogenetic tree for 13 Abies species. Whereas MIG-seq detected 6700 single-nucleotide polymorphisms and exhibited clear clustering of related species with 97%-100% bootstrap support for all branches of the phylogenetic tree. Hence, with a complementary combination, quick, simple, and economical analysis can be performed in a wide range of genomic studies, including molecular phylogeny, as well as for investigating genetic differentiation or genetic identification among species, hybrids, and populations, and even among clones and cultivars, as a DNA barcoding technique.

Endemic organisms of ancient lakes have been studied as models to understand processes of speciation and adaptive radiation. However, it remains unclear how ancient lakes play roles in genetic and phenotypic diversity of freshwater mollusks. In the present study, we focus on viviparid freshwater snails in the ancient lakes of East and Southeast Asia (Japan and China) to address this question. Using molecular phylogenetic analyses based on mitochondrial (COI, 16S) and nuclear genes (18S, 28S, H3), we show that patterns of species diversification in viviparid lineages. Colonization to ancient lakes occurred independently in China and Japan at least four times, with subsequent diversification into more than two species within each lake group. Morphological analyses of fossil related viviparids suggest parallel phenotypic evolution occurred in the different lakes and ages. Each lake contained a single lineage which was phenotypically diversified relative to those from other sites. Using genome‐wide SNPs obtained by MIG‐seq, we also examined the genetic structure of three Japanese viviparids, including two endemic species of ancient Lake Biwa. The results suggest that these two species diversified from the population of the third species living in wetlands surrounding the lake. These findings suggest that rapid diversification of lineages and phenotypic divergence can occur in ancient lakes compared to other habitats. Formation of large lakes probably promotes speciation and phenotypic divergence as a result of adaptation into different microhabitats. High numbers of ancient lakes could be a driver of species diversity in Asian viviparid snails.

Phylogenetic incongruence has frequently been encountered among different molecular markers. Recent progress in molecular phylogenomics has provided detailed and important information for evolutionary biology and taxonomy. Here we focused on the freshwater viviparid snails ( Cipangopaludina chinensis chinensis and C. c. laeta ) of East Asia. We conducted phylogenetic analyses and divergence time estimation using two mitochondrial markers. We also performed population genetic analyses using genome-wide SNPs. We investigated how and which phylogenetic patterns reflect shell morphology. The results showed these two species could be separated into four major mitochondrial clades, whereas the nuclear clusters supported two groups. The phylogenetic patterns of both mtDNA and nDNA largely reflected the geographical distribution. Shell morphology reflected the phylogenetic clusters based on nDNA. The findings also showed these two species diversified in the Pliocene to early Pleistocene era, and occurred introgressive hybridisation. The results also raise the taxonomic issue of the two species.

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Edaphic specialization is one of the main drivers of plant diversification and has multifaceted effects on population dynamics. Carex angustisquama is a sedge plant growing only on heavily acidified soil in solfatara fields, where only extremophytes can survive. Because of the lack of closely related species in similar habitats and its disjunct distribution, the species offers ideal settings to investigate the effects of adaptation to solfatara fields and of historical biogeography on the genetic consequences of plant edaphic specialization to solfatara fields. Here, genome‐wide single nucleotide polymorphisms were used to reveal the phylogenetic origin of C. angustisquama, and 16 expressed sequence tag–simple sequence repeat markers were employed to infer population demography of C angustisquama. Molecular phylogenetic analysis strongly indicated that C. angustisquama formed a monophyletic clade with Carex doenitzii, a species growing on nonacidified soil in the sympatric subalpine zone. The result of population genetic analysis showed that C. angustisquama has much lower genetic diversity than the sister species, and notably, all 16 loci were completely homozygous in most individuals of C. angustisquama. Approximate Bayesian computation analysis supported the model that assumed hierarchical declines of population size through its evolutionary sequence. We propose that the edaphic specialist in solfatara fields has newly attained the adaptation to solfatara fields in the process of speciation. Furthermore, we found evidence of a drastic reduction in genetic diversity in C. angustisquama, suggesting that the repeated founder effects associated with edaphic specialization and subsequent population demography lead to the loss of genetic diversity of this extremophyte in solfatara fields.