Genetic Species Identification Research Articles

Development of SSR markers for genetic diversity analysis and species identification in Polygonatum odoratum (Mill.) Druce based on transcriptome sequences.

Polygonatum odoratum (Mill.) Druce is a well-known traditional Chinese herb belonging to the Polygonatum. However, the understanding of the genetic diversity of this species at the molecular level is limited due to the lack of transcriptomic and genomic information. In this study, 37,387 unigenes were assembled based on the transcriptome sequencing of the rhizome of Polygonatum odoratum (Mill.) Druce., and 11,021 single- sequence repeats (SSR) motifs, mainly consisting of single-nucleotide repeats (44.44%), dinucleotides (31.06%), and trinucleotides (22.59%), were identified. Based on these SSR motifs, 9,987 primer pairs of SSR markers were designed and 68 SSR markers were randomly selected for verification, of which 21 SSR markers showed polymorphisms among the 24 Polygonatum odoratum germplasms. Ninety-four alleles were detected: the observed alleles ranged from 2 to 11, the effective alleles varied from 1.086 8 to 4.916 8, the Shannon diversity index was 0.173 2~1.749 7, and the polymorphism information content PIC ranged from 0.076 7 to 0.803 9. Based on our analysis of genetic diversity (SSR genotypes) and population structure, we divided the 24 germplasm resources into two groups, indicating that the germplasm with similar geographical origins can be grouped together. In addition, the primers 'YZ14' and 'YZ47' could effectively distinguished the related species: Polygonatum kingianum Coll.et Hemsl., Polygonatum sibiricum Red., Polygonatum cyrtonema Hua, Polygonatum zanlanscianense Pamp. and Polygonatum odoratum (Mill.) Druce. This is the first study in which a dataset of expressed sequence tag (EST)-SSR markers is constructed for the Polygonatum odoratum (Mill.) Druce, and these newly developed EST-SSR markers provided a very efficient tool for genetic relationship analysis, species identification and marker-assisted selection breeding of Polygonatum odoratum (Mill.) Druce.

Genetic Differentiation Between Sympatric Crustacean Decapods Inhabiting the Mediterranean Sea: Implications to Avoid Larval and Adult Misidentification

ABSTRACTThe conservation of species, especially those with high levels of exploitation and economic interest, relies on the knowledge of their biology and geographical distribution. In the marine realm, similar morphology between species is a common difficulty in identifying sympatric species, especially in early stages of development. Therefore, genetic identification of crustacean species has been shown to be the only way to identify the species. We used a 451‐bp fragment of the 16S rDNA gene to differentiate nine species of decapod crustaceans, five of which are sympatric and heavily exploited in the Mediterranean Sea: Aristeus antennatus (blue and red shrimp), A. virilis (stout red shrimp), A. varidens (striped red shrimp), Aristaeomorpha foliacea (giant red shrimp), Aristaeopsis edwardsiana (scarlet shrimp), Gennadas elegans (graceful blunt‐tail prawn), Gennadas valens (valuable blunt‐tail prawn), Parapenaeus longirostris (deep‐water rose shrimp) and Penaeus kerathurus (camarote prawn). Analysis of the 16S rDNA gene provides clear evidence of genetic differentiation to be used as an easy method to identify these species.

The Genetic Identification of Numerous Apicomplexan Sarcocystis Species in Intestines of Common Buzzard (Buteo buteo).

The common Buzzard (Buteo buteo) was previously shown to transmit two Sarcocystis species (S. glareoli and S. microti) forming cysts in the brains of rodents. Due to a lack of research, the richness of Sarcocystis species spread by these birds of prey is expected to be much higher. A total of 30 samples of the small intestine of the Common Buzzard were collected in Lithuania and subjected to Sarcocystis species identification based on nested PCR of 28S rRNA and ITS1, following the sequencing of amplified DNA fragments. Six known Sarcocystis spp., S. cornixi, S. glareoli, S. halieti, S. kutkienae, S. turdusi, and S. wobeseri, along with three genetically distinct species (Sarcocystis sp. Rod3, Sarcocystis sp. Rod4, and Sarcocystis sp. Rod5), were identified. Phylogenetically, these three potentially new species clustered with Sarcocystis spp. characterised by a rodents-birds life cycle. Sarcocystis spp. employing rodents and birds as their intermediate hosts were detected in 66.7% and 50.0% of samples, respectively. These findings are consistent with the diet preferences of Common Buzzards. Notably, co-infections with two or more species were observed in a half of the samples. Altogether, the obtained results indicate that the Common Buzzard could serve as definitive host of various Sarcocystis species.

Can consumers avoid mislabelling? Genetic species identification provides recommendations for shrimp/prawn products.

Crustaceans of the superfamily Penaeoidea (e.g., shrimps and prawns) are among the most commercially available aquatic products worldwide. However, there are few studies regarding not only the presence but also the characteristics of mislabelling in these food products. Such information would be helpful for consumers in order to avoid the typical problems associated with mislabelling (e.g., health and economic issues). For this reason, this work considers Penaeoidea mislabelling by comparing different products (frozen, fresh, boiled), and sources (hypermarkets, supermarkets and fishmongers) from Spain (Europe). A total of 94 samples from 55 different products were collected, representing 19 different species from 13 genera. Mitochondrial DNA (COI gene) was amplified, revealing mislabelling in almost 30% of supermarket products and almost exclusively found in frozen samples (95% of the total) regardless of its price. In addition, products from the Pacific Ocean seem to be particularly susceptible to mislabelling. All in all, recommendations for the consumer in order to avoid mislabelling of prawns include purchasing them fresh from fishmongers; aquaculture products must not be avoided. This study represents, to our knowledge, the first attempt to provide recommendations to consumers based on DNA analyses in order to avoid mislabelling in food products. Further research is therefore required to provide such recommendations in different food products, particularly those that are processed, packaged and/or frozen. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Timber DNA release using focused ultrasound extraction (FUSE) for genetic species identification

The use of genetic data for timber species and population assignment is a powerful tool for combating the illegal timber trade, but the challenges of extracting DNA from timber have prevented the routine use of genetics as a supply chain management tool. To overcome these challenges, we explored the feasibility of focused ultrasound extraction (FUSE) for rapid DNA release from timber. Using high-pressure ultrasound pulses, FUSE generates a cavitation bubble cloud that disintegrates samples into acellular debris, resulting in the mechanical release of DNA. In this work, FUSE was applied to white oak (Quercus alba) timber shavings to test the feasibility of using FUSE for timber DNA extraction for the first time. Results showed that FUSE processing disintegrated the tissue samples and released significant quantities of DNA. After five minutes of tissue processing DNA quantities of 0.21 ± 0.02 ng/mg, 0.99 ± 0.32 ng/mg, and 0.14 ± 0.01 ng/mg, were released from medium, coarse, and combination shaving groups, respectively. Amplification and sequencing of regions within the matK and rbcL chloroplast genes confirmed that the quality of DNA prepared with FUSE was suitable for PCR and short-read sequencing applications. Overall, these results show that FUSE can serve as a DNA sample preparation method capable of releasing high-quality DNA from timber in a fraction of the time required by conventional extraction methods. Based on the improved efficiency of DNA release with FUSE, ongoing work aims to develop this technology into portable systems that can be used to rapidly prepare timber samples for genetic species identification.

Sharkaeology: Expanding Understandings of Historical Chinese Diaspora Shark Fisheries in Monterey Bay, California, through the Genetic Species Identification of Archaeological Chondrichthyes Remains

Prior to burning down in 1906 CE, Point Alones in the Monterey Bay region of Central California was home to one of the largest Chinese fishing communities in the United States of America. Both historical records and the recovery of numerous cartilaginous fish (Chondrichthyes) vertebrae during archaeological excavations of the village indicate sharks were among the taxonomic groups being regularly harvested by its inhabitants. However, as shark vertebrae are difficult to identify past the family-level using conventional morphology-based approaches, our understanding of the Point Alones shark fishery remains incomplete. In this study, we address this issue by using ancient DNA analysis to assign species-level identifications to a sample of 54 shark vertebrae from the site. We successfully amplified a 173 bp fragment of the mitochondrial cytochrome c oxidase I gene from 47 of the 54 analyzed specimens (87.03%). Our results indicate that Tope Shark (Galeorhinus galeus; n = 39) was the primary focus of the site’s shark fishery, with Brown Smooth-Hound (Mustelus henlei; n = 7) and Leopard Shark (Triakis semifasciata; n = 1) also harvested to a lesser extent. All three of these species are found locally in the waters overlying the continental shelf, suggesting Chinese fishers were harvesting sharks from these coastal environments. While some of the sharks caught by fishers from Point Alones were likely being consumed at the village, historical records suggest a significant number of fins from harvested Tope Sharks were also likely being exported to China and other diaspora communities.

The complete chloroplast genome of Durio zibethinus L. cultivar Ri6 (Helicteroideae, Malvaceae)

Durian, a member of the Malvaceae family, is famous for its delicious fruits, which have strong scents and are rich in nutrients. In this study, we sequenced and characterized the complete chloroplast genome of Durio zibethinus L. 1774 cultivar Ri6, a popular durian cultivar in Vietnam, using the Illumina Hiseq platform. The results showed a circular chloroplast genome composed of a large single copy of 96,115 bp, a small single copy of 20,819 bp, and two inverted repeat regions of 24,185 bp. This genome consisted of 79 protein-coding genes, 30 transfer RNA genes, and four ribosomal RNA genes. The overall GC content of this genome was 35.7%. Phylogenetic analysis inferred from 78 protein-coding regions revealed monophyly of Durio species and a close relationship between D. zibethinus cultivar Ri6 and cultivar Mongthong. This study provides essential information for further studies examining genetic population, breedings, and species identification among Durio taxa and cultivars.

Morphological and genetic identification of an invasive species of the genus Melita (Amphipoda: Melitidae) from the Azov–Black Sea basin

Morphological and genetic identification of an invasive species of the genus Melita (Amphipoda: Melitidae) from the Azov–Black Sea basin

The development of non-destructive sampling methods of parchment skins for genetic species identification.

Parchment, the skins of animals prepared for use as writing surfaces, offers a valuable source of genetic information. Many have clearly defined provenance, allowing for the genetic findings to be evaluated in temporal and spatial context. While these documents can yield evidence of the animal sources, the DNA contained within these aged skins is often damaged and fragmented. Previously, genetic studies targeting parchment have used destructive sampling techniques and so the development and validation of non-destructive sampling methods would expand opportunities and facilitate testing of more precious documents, especially those with historical significance. Here we present genetic data obtained by non-destructive sampling of eight parchments spanning the 15th century to the modern day. We define a workflow for enriching the mitochondrial genome (mtGenome), generating next-generation sequencing reads to permit species identification, and providing interpretation guidance. Using sample replication, comparisons to destructively sampled controls, and by establishing authentication criteria, we were able to confidently assign full/near full mtGenome sequences to 56.3% of non-destructively sampled parchments, each with greater than 90% of the mtGenome reference covered. Six of eight parchments passed all four established thresholds with at least one non-destructive sample, highlighting promise for future studies.

Assembly and characterization of the complete mitochondrial genome of Descurainia sophia: a medical plant producing glucosinolate

As a commonly used traditional Chinese medicine, Descurainia sophia has various reported pharmacological activities such as prevention of chronic diseases, cardiovascular protection, neuroprotection, anticancer, antioxidant, and has high nutritional values, but its mitochondrial genome (mitogenome) has not been reported. In this study, the D. sophia mitogenome was sequenced, assembled and annotated using next generation sequencing technologies on the Illumina HiSeq and PacBio Sequel platform. The results showed that the D. sophia mitogenome was a circular DNA molecule with the length of 265,457 bp and the GC content of 44.78%, encoding unique 56 genes, including 35 protein coding genes, 18 tRNA genes and 3 rRNA genes. We analyzed codon preference, repeated sequences, DNA sequence transformation, phylogenetic relationship, RNA editing and synteny in the D. sophia mitogenome. Based on the DNA sequences of mitogenomes, the phylogenetic and synteny analysis indicated that D. sophia was more closely related to Boechera stricta, and the mitogenome of D. sophia underwent frequent genome recombination. In this study, we obtained the complete mitogenome of D. sophia, which can provide valuable data support for future studies on genetic characteristics, phylogenetic relationships, species identification and development of new molecular markers in D. sophia.

Application of biomolecular techniques on tsetse fly puparia for species identification at larvipostion sites.

Puparia are commonly found in tsetse fly larviposition sites during studies on larval ecology. This chitinous shell is representative of past or ongoing exploitation of these sites by tsetse flies. The morphological characteristics of the puparium are not sufficiently distinctive to allow identification of the species. This study explores the applicability of biomolecular techniques on empty puparia for tsetse fly species identification. Five techniques were compared for DNA extraction from tsetse fly puparia, 1/Chelex® 100 Resin, 2/CTAB, 3/Livak's protocol, 4/DEB + proteinase K and 5/QIAamp® DNA Mini kit, using two homogenisation methods (manual and automated). Using a combination of two primer pairs, Chelex, CTAB, and DEB + K proved the most efficient on fresh puparia with 90, 85, and 70% samples identified, respectively. Shifting from fresh to one- to nine-month-old puparia, the Chelex method gave the best result allowing species identification on puparia up to seven months old. The subsequent testing of the Chelex extraction protocol identified 152 (60%) of 252 field-collected puparia samples at species level. The results show that reliable genetic identification of tsetse flies species can be performed from empty puparia, what can prove of great interest for future ecological studies on larviposition sites. The Chelex technique was the most efficient for DNA extraction, though the age-limit of the samples stood at seven months, beyond which DNA degradation probably compromises the genetic analysis.

The Diversity of Parasitoids and Their Role in the Control of the Siberian Moth, Dendrolimus sibiricus (Lepidoptera: Lasiocampidae), a Major Coniferous Pest in Northern Asia.

The Siberian moth, Dendrolimus sibiricus Tschetv., 1908 (Lepidoptera: Lasiocampidae) is a conifer pest that causes unprecedented forest mortality in Northern Asia, leading to enormous ecological and economic losses. This is the first study summarizing data on the parasitoid diversity and parasitism of this pest over the last 118 years (1905-2022). Based on 860 specimens of freshly reared and archival parasitoids, 16 species from two orders (Hymenoptera and Diptera) were identified morphologically and/or with the use of DNA barcoding. For all of them, data on distribution and hosts and images of parasitoid adults are provided. Among them, the braconid species, Meteorus versicolor (Wesmael, 1835), was documented as a parasitoid of D. sibiricus for the first time. The eastern Palaearctic form, Aleiodes esenbeckii (Hartig, 1838) dendrolimi (Matsumura, 1926), status nov., was resurrected from synonymy as a valid subspecies, and a key for its differentiation from the western Palaearctic subspecies Aleiodes esenbeckii ssp. esenbecki is provided. DNA barcodes of 11 parasitoid species from Siberia, i.e., nine hymenopterans and two dipterans, represented novel records and can be used for accurate molecular genetic identification of species. An exhaustive checklist of parasitoids accounting for 93 species associated with D. sibirisus in northern Asia was compiled. Finally, the literature and original data on parasitism in D. sibiricus populations for the last 83 years (1940-2022) were analysed taking into account the pest population dynamics (i.e., growth, outbreak, decline, and depression phases). A gradual time-lagged increase in egg and pupal parasitism in D. sibiricus populations was detected, with a peak in the pest decline phase. According to long-term observations, the following species are able to cause significant mortality of D. sibiricus in Northern Asia: the hymenopteran egg parasitoids Telenomus tetratomus and Ooencyrtus pinicolus; the larval parasitoids Aleiodes esenbeckii sp. dendrolimi, Cotesia spp., and Glyptapanteles liparidis; and the dipteran pupal parasitoids Masicera sphingivora, Tachina sp., and Blepharipa sp. Their potential should be further explored in order to develop biocontrol programs for this important forest pest.

Morphological and genetic identification of Halophila species and a new distribution record of Halophila nipponica at the Tanjung Adang Laut shoal, Johor, Malaysia.

The Halophila species exhibit complex characteristics due to their high degree of variation across different bioregions. This study delves into the intricate characteristics of Halophila species in the Tanjung Adang Laut shoal, Johor, Malaysia, and offers valuable insights through morphological and genetic evidence. Employing internal transcribed sequences (ITS), we investigated the phylogeny of Halophila species, revealing distinct clades for H. ovalis, H. major, H. spinulosa, and the newly recorded H. nipponica. Notably, H. nipponica from the Tanjung Adang Laut shoal formed a conspecific relationship with its counterparts from Japan and Korea (98.3-98.5% similarity; 5-11 bp differences). Morphologically, distinguishing features, including the ratio of the half-lamina width (1:4.76-6.13 mm) and cross-vein count (4-7 pairs), supported the identification of H. nipponica. Genetic distance analyses revealed differences between H. nipponica, H. ovalis, and H. major, indicating haplotype diversity. Geographical variations were evident, as H. nipponica presented unique haplotypes (H24) in its clade. The 47 haplotypes network identified significant mutation sites, providing a comprehensive understanding of genetic and morphological distinctions. In conclusion, this study highlights the intricate characteristics and phylogeny of Halophila species in the Tanjung Adang Laut shoal, Johor, and provides valuable insights into their genetic and morphological diversity.

Citizen science approach for genetic species identification in a local French seafood speciality

In coastal regions of France, seafood is a key element of traditional cuisine and is valued by consumers as quality food. However, in the last decades, the mislabelling of food products has undermined consumers' confidence in their food choices. In this study, we used genetic identification of the seafood species used to prepare a traditional dish of the city of Sète, to initiate a discussion on food labelling and sustainability. The dish, named “Tielle sétoise", is a pie traditionally filled with octopus cooked in a spicy tomato sauce. The recent substitution of octopus by jumbo flying squid (Dosidicus gigas) has triggered debates among locals about how the use of non-native cephalopod species impacts the flavour of tielles. To test this hypothesis, we coordinated a tasting event involving 35 testers from the local population and used CO1-gene metabarcoding to identify the species composition in 25 different tielles. Besides locally available octopuses’ species, including common commercial species Eledone cirrhosa, E. moschata and Octopus vulgaris, we found jumbo flying squid in 17 out of 25 tielles, of which eight (35%) were mislabelled as octopus-based products. Contrary to local belief, anonymous blind-tasting evaluations showed no significant correlation between the flavour or price of a tielle and the cephalopod composition of its filling. Our results support the impact of texture, acidity, and spices on flavour, suggesting that flavour depends more on how tielles are prepared than on the cephalopod species used. The participants in our study expressed their willingness to make informed choices about purchasing tielles based on the carbon footprint and its impact on cephalopod stocks. Our results call for further research to enable citizens to make informed food choices. Our study also highlights the need for improved labelling of traded cephalopods to improve communication between the food industry and society, as well as the possibility of evaluating this with citizen science.

Detailed integrative taxonomic analysis reveals large-scale species misidentification of barnacles based on DNA barcoding data

Abstract Morphological species identification is the traditional way to identify species. More recently, biodiversity studies have depended on DNA barcoding for species identification. Mismatches between morphological and genetic species identification caused by voucher specimen misidentifications lead to ambiguous species identification. We used barnacles of the genera Amphibalanus and Balanus to investigate this issue. The purpose of this study was to assess the accuracy of the Barcoding of Life database and determine the true species affinity of three inconsistent barnacle barcode index numbers using an integrative taxonomic approach. To this end, we re-identified barcoded voucher specimens, or we identified specimens based on a dichotomous key that we barcoded subsequently. We found that 75% of Barcoding of Life clades representing genetic species showed inconsistent species assignments. One clade (BOLD: AAG0069), containing mostly unidentified Balanus sp. individuals, was morphologically and genetically Balanus balanus (Linneaus, 1758); a second clade (BOLD: AAB1410), containing specimens mostly identified as B. balanus, turned out to be morphologically and genetically Balanus crenatus Bruguière, 1789; and a third clade (BOLD: AAE2482), containing different species of Amphibalanus, was Amphibalanus improvisus (Darwin, 1854). This study showed that morphological species identification and taxonomic expertise can resolve the widespread misidentification in barcoding data. To prevent this problem in the future, morphological taxonomy and molecular species identification need to interact more closely.

Analysis of <i>BMP2</i> gene polymorphism of bone morphogenetic protein-2 in reindeer

The BMP2 gene of reindeer was study by Sanger sequencing. The BMP2 gene is involved in the formation of bone tissue and skeletal muscle in mammals. The BMP2 gene is associated with an increase in height, size, and body weight in productive animals. For the first time, the nucleotidesequence of the coding and regulatory regions of the BMP2 gene was determined in populations of wild and domestic reindeer.As a result, a segment of the reindeer BMP2 candidate gene was sequence, including the first untranslated and second exons. Loci with low (exon1) and high (exon2) degree of polymorphism identified.Single nucleotide mismatches with the reference genome (white-tailed deer (Odocoileus virginianus texanus) genome) identified, which can be used for phylogenetic analysis of the evolution of orthologue genes, as well as for genetic identification of species. Twelve polymorphic loci of two types were identified: in/del and SNP. The most significant substitutions were also determined in accordance with the change in the amino acid composition of the protein and the chemical properties of the replaced amino acids. Calculations were made of the occurrence of genotypes and alleles according to the identified variants of genetic polymorphism in the analyzed populations of reindeer (Nenets and Evenk breeds, wild reindeer).The object of research was wild and domestic reindeer on the farms of the Taimyr Peninsula and Evenkia. The material for the study was DNA isolated by the classical phenol method from the blood of domestic reindeer of two breeds - Nenets (n=20) and Evenki (n=20), as well as from tissue samples of wild reindeer (n=20).The aim of the study was to search for and select potential variants of genetic polymorphism in the BMP2 gene as molecular genetic markers that can be recommend for use in the practice of reindeer breeding to increase meat productivity.For the first time, the nucleotide sequence of significant regions of the reindeer BMP2 gene was determined. The polymorphic loci in the BMP2 gene identified as a result of the studies had differences in the frequency of occurrence of alleles of mutant and wild types in the studied samples of domestic reindeer of the Nenets and Evenk breeds, as well as in the sample of wild reindeer. Differences in occurrence indicate the effect of selection factors on the region of the BMP2 gene. The revealed genetic variability of the studied region in reindeer breeds contrasting in productivity is a preliminary confirmation of the influence of genetic polymorphism in the BMP2 gene on the variability of phenotypes in terms of height and weight indicators. Indicators of growth and live weight are key to the formation of the meat productivity of reindeer. The results of studies of the effect of BMP2 gene polymorphism on growth and weight parameters in other animal species suggest that some of the identified variants of genetic polymorphism in the studied region of the BMP2 gene may turn out to be casual mutations that can affect the formation of quantitative traits in domestic reindeer.

Morphological and Genetic Identification of Head Taunsa Barrage Fish Species

The current study aims to construct a thorough barcoding reference database of fishes in the Head Taunsa Barrage and assess the usefulness of employing the COI gene for fish species identification. A total of 15 genera, 10 families, and 7 orders of fish were used to collect a total of 19 mitochondrial COI barcode sequences. These sequences had an average length of 800 base pairs. Within species, genera, families, orders, and classes, the average Kimura two-parameter (K2P) distances were 0.97%, 0.99%, 1.23%, and 1.26%, respectively. According to their taxonomic classification, species were commonly clustered in the K2P neighbor-joining trees based on the sequence. DNA barcoding was employed in this study to identify species with a high degree of accuracy. Moreover, it was concluded that COI sequencing can be used to recognize fish species.

Genetic Species Identification Using ycf1b, rbcL, and trnH-psbA in the Genus Pinus as a Complementary Method for Anatomical Wood Species Identification

This study proposes the use of genetic analysis as a complementary method for species identification in the genus Pinus, particularly in cases where anatomical identification is challenging. Pinus species were grouped based on anatomical similarities, and the efficacy of using ycf1b, which is the most variable for Pinus species identification, and rbcL, which is a suggested DNA barcode for land plants, was evaluated within each group. Sequences for each species were obtained from the National Center for Biotechnology Information database and were used to perform phylogenetic analysis. Among the species in Group 1 (P. echinata, P. elliottii, P. ponderosa, P. radiata, P. rigida, P. taeda, and P. virginiana), rbcL was only effective in identifying P. radiata and P. ponderosa, while ycf1b classified five species. An additional DNA barcode, trnH-psbA, was needed to identify P. radiata and P. taeda. In Group 2 (P. densiflora, P. sylvestris, and P. thunbergii), most species were identified using both rbcL and ycf1b, with the exception of possible hybrids of P. densiflora and P. sylvestris. In Group 3 (P. koraiensis and P. strobus), two species were identified using rbcL and ycf1b. Combining genetic species identification with anatomical identification can accurately identify species of the genus Pinus.

On the Species Identification of Two Non-Native Tilapia Species, Including the First Record of a Feral Population of Oreochromis aureus (Steindachner, 1864) in South Korea.

Tilapia is an invasive species that has become widely distributed around the world. In Korea, introduced tilapia into its aquatic ecosystem for the first time with a species from Thailand in 1955, and later additionally introduced two more species from Japan and Taiwan, thus securing a total of three species of tilapia (O. niloticus, O. mossambicus and O. aureus) as food resources. Since then, O. niloticus has been reported to inhabit certain streams with thermal effluent outlets. Morphological species identification is very difficult for tilapia and a combined analysis of morphological and molecular-based species identification is therefore necessary. This study investigated a tilapia population that inhabits a thermal effluent stream (Dalseo Stream) in Daegu Metropolitan City, Korea, in order to conduct a morphological and genetic species identification of this population. In total, 37 tilapia individuals were sampled. The results of the morphological and genetic species identification analyses found that two species, O. aureus and O. niloticus, inhabit the Dalseo Stream. In Korea, the habitat of the O. niloticus natural population has been reported, but the O. aureus natural population has not been reported. Thus, we observed for the first time that a new invasive species, O. aureus, inhabits a stream in Korea. They are known to cause disturbances to aquatic organisms (e.g., fish, aquatic insects, plankton, aquatic plants) and the habitat environment (e.g., water quality, bottom structure). Accordingly, it is important to study the ecological effects of O. aureus and O. niloticus on the corresponding freshwater ecosystem closely and to prepare a management plan to prevent the spread of these species, as they are notoriously invasive.

Genetic identification of the original plant species for Mentha Herb listed in the Japanese Pharmacopoeia and analyses of their essential oil composition

Mentha arvensis Linné var. piperascens Malinvaud is an original plant species for "Mentha Herb (Hakka, ハッカ)" and "Mentha Oil (Hakka-yu, ハッカ)" listed in the Japanese Pharmacopoeia, whereas Mentha canadensis L. is that of "Mint oil, partly dementholised" listed in the European Pharmacopoeia. Although these two species are thought to be taxonomically identical, there are no data on whether the source plants of the Mentha Herb products distributed in the Japanese market are actually M. canadensis L. This is an important issue for international harmonization of the Japanese Pharmacopoeia and European Pharmacopoeia. In this study, 43 Mentha Herb products collected from the Japanese market and two plant samples of the original species of Japanese Mentha Herb harvested in China were identified by sequence analyses of the rpl16 regions in the chloroplast DNA, and the composition of their ether extracts was analyzed by GC-MS. Almost all samples were identified as M. canadensis L., and the main component of their ether extracts was menthol, although there were variations in their composition. However, there were some samples thought to be derived from other Mentha species, even though their main component was menthol. For quality control of Mentha Herb, it is important to be sure of not only the original plant species but also the composition of the essential oil and amount of menthol as the characteristic compound.