• Journal of applied mathematics & informatics
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• v.25 no.1_2
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• pp.455-470
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• 2007

In phylogenetic tree construction the neighbor-joining algorithm is the most well known method which constructs a trivalent tree from a pairwise distance data measured by DNA sequences. The core part of the algorithm is its cherry picking criterion based on the tree structure of each quartet. We give a generalized version of the criterion based on the exact box model of quartets, known as the tight span of a metric. We also show by experiment why neighbor-joining and the quartet consistency count method give similar performance.

• Communications of the Korean Mathematical Society
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• v.25 no.1
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• pp.149-160
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• 2010

Among the distance based algorithms in phylogenetic tree reconstruction, the neighbor-joining algorithm has been a widely used and effective method. We propose a new algorithm which counts the number of consistent quartets for cherry picking with tie breaking. We show that the success rate of the new algorithm is almost equal to that of neighbor-joining. This gives an explanation of the qualitative nature of neighbor-joining and that of dissimilarity maps from DNA sequence data. Moreover, the new algorithm always reconstructs correct trees from quartet consistent dissimilarity maps.

• Communications of the Korean Mathematical Society
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• v.34 no.3
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• pp.1005-1014
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• 2019

A new simple method is proposed for reconstructing phylogenetic trees, which we call the spectral method. The most common distance based method is the neighbor-joining method which is based on the minimum evolution principle. The spectral method shows similar performance to the neighbor-joining method for simulated data generated by seq-gen. For real data, the spectral method shows much better performance than the neighbor-joining method. Hence it can be a complementary method for reconstructing phylogenetic trees.

• Korean Journal of Plant Taxonomy
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• v.36 no.1
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• pp.21-40
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• 2006

We examined nrDNA ITS sequences from 16 taxa of Polygonum sect. Persicaria(Polygonaceae) in Korea to infer relationships among the taxa within the section. A neighbor-joining tree obtained from the analysis of the ITS sequences suggest that the ITS region was useful inferring the phylogenetic relationships among the taxa. The neighbor-joining tree indicates that P.amphibium is clearly separated from the other Korean taxa. The tree also reveals the presence of five major groups in the Korean taxa of the section; 1) P. lapathifolium var. lapathifolium, 2) P. persicaria and P. viscoferum, 3) P. orientale and P. viscosum, 4) P. japonicum and 5) a group including the remaining taxa. these relationships depicted on the ITS tree are largely congruent with those inferred from morphological and anatomical characters.

• Animal Systematics, Evolution and Diversity
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• v.16 no.2
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• pp.203-211
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• 2000

Partial mitochondrial 16S rDNA and COI gene were amplified using PCR and sequenced for four species of oysters in Korea. Phylogenetic relationships among them were inferred from their aligned sequences by neighbor-joining method. The sequence comparison data of two mitochondrial genes showed that the genetic distinction between two oyster genera (Crassostreo and Ostrea) was obvious. Phylogenetic analysis based on the nucleotide sequences and A+T percentage of two genes indicates that C. gigas and C. nippona strongly formed a sister group and then C. ariakensis was clustered with the clade although that based on amino acid sequences of COI gene by neighbor-joining method represented different phylogenetic tree.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.686-689
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• 2003

A Gene content phylogenetic tree and a 16S rRNA based phylogenetic tree were compared for 9 Archaea and 15 Proteobacteria, whole-genome sequenced, by neighbor joining and bootstrap methods (n=1000). Ratio of conserved COG (clusters of orthologous groups of proteins) to ortholog revealed that they were within the range of 4.60% (Mezorhizobium loti) or 56.57% (Mycoplasma genitalium), The diversity of ratio meant the Possibility of searching for useful genes, as they possess peculiar genes. The gene content tree and the 16S rDNA tree showed coincidence and discordance in Archaea and Proteobacteria.

• Korean Journal of Plant Taxonomy
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• v.46 no.2
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• pp.163-174
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• 2016

Gnetum (Gnetaceae, Gnetales) is a gymnosperm genus with ca. 35 species distributed in tropical forests around the world. Due to its dioecious habit and lack of diagnostic characters from vegetative tissue, the identification of Gnetum species is not easy without seeds or reproductive structures. To identify and verify their phylogenetic positions, we applied DNA barcoding to Cambodian Gnetum collections gathered between 2010 and 2015, with previously designed cp matK gene primers. We newly sequenced partial matK sequences from 72 Gnetum collections, 43 out of 72 from Cambodia, and analyzed 115 Gnetum accessions using the neighbor-joining method. The resulting neighbor-joining tree categorized Cambodian Gnetum samples into three clades of species: G. macrostachyum, G. montanum, and G. aff. gracilipes. The recognition of G. aff. gracilipes in Cambodia is reported here for the first time. Taxonomic information for the three recognized Cambodian Gnetum species is provided and the benefits of the taxonomic reevaluation assisted by DNA barcoding are emphasized in this work.

• KSBB Journal
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• v.18 no.1
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• pp.39-44
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• 2003

A Gene content phylogenetic tree and a 16s rRNA based phylogenetic tree were compared for 33 whole-genome sequenced procaryotes, neighbor joining and bootstrap methods (n=1,000). Ratio of conserved COG (clusters of orthologous groups of proteins) to orthologs revealed that they were within the range of 4.60% (Mezorhizobium loti) or 56.57% (Mycopiasma genitalium). This meant that the ratio was diverse among analyzed procaryotes and indicated the possibility of searching for useful genes. Over 20% of orthologs were independent among the same species. The gene content tree and the 16s rDNA tree showed coincidence and discordance in Archaeabacteria, Proteobacteria and Firmicutes. This might have resulted from non-conservative genes in the gene content phylogenetic tree and horizontal gene transfer. The COG based gene content tree could be regarded as a midway phylogeny based on biochemical tests and nucleotide sequences.

• Journal of Life Science
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• v.22 no.3
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• pp.293-297
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• 2012

The movement of vesicles from the neuronal cell body to specific destinations requires molecular motors. The squid giant axon represents a powerful model for studies of the axonal transport mechanism because the axoplasm can readily be separated from the sheath by simple extrusion. In a previous study, vesicular movements in the axoplasm of the squid giant axon were inhibited by the kinesin antibody. In the present study, we cloned and sequenced the cDNAs for squid brain KIFs. Amplification of the conserved nucleotide sequences of the motor domain by polymerase chain reaction (PCR) using first-strand cDNAs of the squid optic lobe identified six new KIF proteins. Motif analysis of the motor domains revealed that the squid KIFs are homologous to the consensus sequences of the mouse KIFs. The phylogenetic tree generated by using the maximum parsimony (MP) method, the neighbor-joining (NJ) method, the minimum evolution (ME) method, and the maximum likelihood (ML) method showed that squid KIFs are closest to mouse KIFs. These data prove the phylogenetic relationships between squid KIFs and mouse ones.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.12
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• pp.1696-1700
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• 2005

Five China native cattle breeds have been characterized by using 10 microsatellite DNA markers. The studied populations can be divided into five groups: Luxi cattle, Nanyang cattle, Jinnan cattle, Qinchuan cattle and Yanbian cattle. Allele frequencies were calculated and used for the characterization of the breeds and the study of their genetic relationships. Heterozygosity, polymorphism information content, the effective number of alleles was calculated. Nei' standard genetic distance (1978) was calculated and used for a neighbor-joining tree construction. NJ tree showed that Luxi cattle, Nanyang cattle, Jinnan cattle and Qinchuan cattle are closely related, whereas Yanbian cattle are clearly distinct from other four populations. The genetic relationship of five breeds corresponds to their history and geographic origins. This work analyzes the recent origin of these populations and contributes to the knowledge and genetic characterization of China native breeds.