RESUMO
Comparative plastomics approaches have been used to identify available molecular markers for different taxonomic level studies of orchid species. However, the adoption of such methods has been largely limited in phylogeographic studies. Therefore, in this study, Dendrobium huoshanense, an endangered species with extremely small populations, was used as a model system to test whether the comparative plastomic approaches could screen available molecular markers for the phylogeographic study. We sequenced two more plastomes of D. huoshanense and compared them with our previously published one. A total of 27 mutational hotspot regions and six polymorphic cpSSRs have been screened for the phylogeographic studies of D. huoshanense. The cpDNA haplotype data revealed that the existence of haplotype distribution center was located in Dabieshan Mts. (Huoshan). The genetic diversity and phylogenetic analyses showed that the populations of D. huoshanense have been isolated and evolved independently for long period. On the contrary, based on cpSSR data, the genetic structure analysis revealed a mixed structure among the populations in Anhui and Jiangxi province, which suggested that the hybridization or introgression events have occurred among the populations of D. huoshanense. These results indicated that human activities have played key roles in shaping the genetic diversity and distributional patterns of D. huoshanense. According to our results, both two markers showed a high resolution for the phylogeographic studies of D. huoshanense. Therefore, we put forth that comparative plastomic approaches could revealed available molecular markers for phylogeographic study, especially for the species with extremely small populations.
RESUMO
The aim of the current study was to elucidate the phylogeographic history of Dendrobium moniliforme, an endangered orchid species, based on two chloroplast DNA (cpDNA) markers (trnC-petN and trnE-trnT). One hundred and thirty-five samples were collected from 18 natural populations of D. moniliforme covering the entire range of the Sino-Japanese Floristic Region (SJFR) of East Asia. A total of 35 distinct cpDNA haplotypes were identified in these populations, of which 23 haplotypes were each present in only one sample and thus restricted to a single population. The significantly larger NST value (0.586) than GST (0.328) (p < 0.05) demonstrated the presence of strong phylogeographic structure. Phylogenetic analyses indicated that all haplotypes were clustered into two lineages. The genetic diversity of D. moniliforme was high at the species level, reflected in its haplotype diversity (Hd=0.8862), nucleotide diversity (Pi=0.00361), total genetic diversity (HT=0.9011), and significant differentiation (ΦST=0.5482). Based on mismatch distribution analysis and neutrality tests, population expansion was evident in all sampled populations and also in all populations sampled in mainland China. Three refuge areas were identified, one each in southwestern China, central-southeastern China, and the CKJ (Taiwan, Japan and Korea) Islands. The results supported the hypothesis that glacial refugia were maintained on different spatial-temporal scales in the SJFR during the last glacial maximum or earlier cold periods, suggesting that Quaternary refugial isolation promoted allopatric speciation of D. moniliforme in East Asia.
Assuntos
DNA de Cloroplastos , Dendrobium/genética , Filogeografia , Espécies em Perigo de Extinção , Ásia Oriental , Variação Genética , Filogenia , Análise de Sequência de DNARESUMO
The complete chloroplast (cp) genome sequence of Dendrobium nobile, an endangered and traditional Chinese medicine with important economic value, is presented in this article. The total genome size is 150,793 bp, containing a large single copy (LSC) region (84,939 bp) and a small single copy region (SSC) (13,310 bp) which were separated by two inverted repeat (IRs) regions (26,272 bp). The overall GC contents of the plastid genome were 38.8%. In total, 130 unique genes were annotated and they were consisted of 76 protein-coding genes, 30 tRNA genes and 4 rRNA genes. Fourteen genes contained one or two introns.
Assuntos
Cloroplastos/genética , Dendrobium/genética , Genoma de Cloroplastos/genética , Composição de Bases/genética , DNA de Cloroplastos/genética , Genes de Plantas/genética , Genes de RNAr/genética , Tamanho do Genoma/genética , Genoma de Planta/genética , Íntrons/genética , Filogenia , RNA de Transferência/genética , Sequências Repetitivas de Ácido Nucleico/genética , Análise de Sequência de DNA/métodos , Sequenciamento Completo do Genoma/métodosRESUMO
The choice of the generic drug is reasonable if there is evidence for its therapeutic equivalence with the brand-name drug. However, the reduced effectiveness of switching from brand-name drug to generic drug is not rare. The impact of brand-name worship and expectation psychology on drug efficacy is noteworthy to report. A 45-year-old woman suffered from depression mood disorder. She experienced profound improvement in her depressive symptoms after a switch from domestic generic venlafaxine to imported brand-name counterpart. The interview showed that the woman has a strong brand-name drug worship and expectation psychology, which is representative, typical and popular in China especially in vast rural areas. Medication education does not work too much. The brand-name drug worship and expectation psychology might improve drug efficacy when patient is switched from generic drug to branded medication.
