RESUMO
In the Supplementary Information file originally published with this Letter, the authors mistakenly omitted Supplementary Table 14; this has now been amended.
RESUMO
The genus Liriodendron belongs to the family Magnoliaceae, which resides within the magnoliids, an early diverging lineage of the Mesangiospermae. However, the phylogenetic relationship of magnoliids with eudicots and monocots has not been conclusively resolved and thus remains to be determined1-6. Liriodendron is a relict lineage from the Tertiary with two distinct species-one East Asian (L. chinense (Hemsley) Sargent) and one eastern North American (L. tulipifera Linn)-identified as a vicariad species pair. However, the genetic divergence and evolutionary trajectories of these species remain to be elucidated at the whole-genome level7. Here, we report the first de novo genome assembly of a plant in the Magnoliaceae, L. chinense. Phylogenetic analyses suggest that magnoliids are sister to the clade consisting of eudicots and monocots, with rapid diversification occurring in the common ancestor of these three lineages. Analyses of population genetic structure indicate that L. chinense has diverged into two lineages-the eastern and western groups-in China. While L. tulipifera in North America is genetically positioned between the two L. chinense groups, it is closer to the eastern group. This result is consistent with phenotypic observations that suggest that the eastern and western groups of China may have diverged long ago, possibly before the intercontinental differentiation between L. chinense and L. tulipifera. Genetic diversity analyses show that L. chinense has tenfold higher genetic diversity than L. tulipifera, suggesting that the complicated regions comprising east-west-orientated mountains and the Yangtze river basin (especially near 30° N latitude) in East Asia offered more successful refugia than the south-north-orientated mountain valleys in eastern North America during the Quaternary glacial period.
Assuntos
Genoma de Planta , Liriodendron/genética , Filogenia , Evolução Biológica , China , Cromossomos Artificiais Bacterianos , Elementos de DNA Transponíveis , Ásia Oriental , Ligação Genética , Magnoliopsida/genética , América do Norte , Filogeografia , Proteínas de Plantas/genética , Polimorfismo de Nucleotídeo ÚnicoRESUMO
PREMISE OF THE STUDY: Tetranucleotide microsatellite markers were developed for the first time in Pinus massoniana Lamb. to facilitate studies of population and conservation biology in this species. METHODS AND RESULTS: Ten tetranucleotide microsatellite primer pairs were developed using dual suppression PCR. Seven, six, and eight of the primer pairs exhibited cross-species transferability to P. thunbergii, P. densiflora, and P. luchuensis, respectively. The number of alleles ranged from 1 to 31 per locus across four pine species. CONCLUSIONS: Considering its advantage over dinucleotide microsatellites in generating fewer artifacts arising from stutter bands, this tetranucleotide microsatellite panel will facilitate future population and conservation biological studies in P. massoniana. Six to eight markers can also be used in studies of three congeneric species.
Assuntos
Primers do DNA/genética , DNA de Plantas/análise , Loci Gênicos , Genoma de Planta , Repetições de Microssatélites , Pinus/genética , Alelos , Conservação dos Recursos Naturais , DNA de Plantas/genética , Frequência do Gene , Triagem de Portadores Genéticos/métodos , Heterozigoto , Nucleotídeos/genética , Reação em Cadeia da Polimerase , Polimorfismo Genético , Especificidade da EspécieRESUMO
To improve the amplified fragment length polymorphism assay, dual-suppression PCR was introduced into the preamplification step of the assay. The dual-suppression PCR blocked completely the amplification of fragments with the same sequence (Bsp1407I-Bsp1407I or NlaIII-NlaIII) at both ends and amplified selectively fragments with different adaptor sequences (Bsp1407I-NlaIII) at each end. Two protocols, referred to as A and B, were established for species with medium- and large-sized genomes, respectively. Both protocols incorporated the dual-suppression PCR. Protocol A resulted in high-quality electrophoretic profiles for black cottonwood and rice, which have medium-sized genomes. In protocol B, an intensely selective PCR step was added to protocol A. Protocol B yielded profiles for Japanese black pine and Japanese cedar that were improved significantly relative to protocol A: the number of strong peaks increased and that of low peaks decreased. Japanese black pine and Japanese cedar have large genomes. The optimal profiles were generated with a total of eight or nine selective nucleotides.