A molecular phylogeny of wild and cultivated Echinochloa in East Asia inferred from non-coding region sequences of trnT-L-F

The phylogenetic relationship among 30 accessions belonging to nine species of the genus Echinochloa Beauv. was studied on the basis of the sequence of three non-coding regions ( trn T-L, trn L-F intergenic spacers, and trn L intron) of chloroplast DNA (cpDNA). A strict consensus parsimonious tree of the three most parsimonious trees derived from 25 polymorphic sites (six indels and 19 substitutions) in the total sequences, ranging from 1715–1760 bp, represented five groups: (i) Echinochloa oryzicola Vasing. and Echinochloa stagnina Beauv. from Thailand; (ii) Echinochloa crus-galli Beauv. complex; (iii) Echinochloa crus-pavonis Schult; (iv) Echinochloa colonum Link. and Echinochloa frumentacea Link.; and (v) the African species, Echinochloa obtusiflora Stapf and Echinochloa stagnina . Japanese barnyard millet ( Echinochloa esculenta H. Scholz) and various weedy varieties of E. crus-galli and Echinochloa oryzoides Fritsch had quite similar sequences and formed the E. crus-galli complex, which was characterized by six substitutions. A cultivated form of E. oryzicola (Mosuo barnyard millet) and various morphological and agronomical forms of E. oryzicola were characterized by two indels. Indian barnyard millet ( E. frumentacea ) and its wild counterpart ( E. colonum ) were characterized by five substitutions. Domestication as millets and adaptation to paddy environments as mimic weeds might occur after the divergence of species in the Asian Echinochloa .     

Discovery of single nucleotide polymorphisms in soybean using primers designed from ESTs

Discovery of single nucleotide polymorphisms (SNPs), including small insertions and deletions (indels), is one of the hot topics in genetic research. SNPs were surveyed using nine soybean genotypes from Korea. Sequence variations in a total of 110 genes from GenBank among the nine genotypes were studied using genomic DNA as a template. Direct fluorescent dideoxynucleotide sequencing data of PCR products from primers designed from soybean ESTs were analyzed by SeqScape software to ensure high accuracy. Approximately 70% of the primer sets produced a single PCR product from which reliable sequence data were obtained, and 23.6% of these had at least one SNP. Overall, a total of 110 ESTs for SNPs were screened in 33,262 bp, consisting of 16,302 bp from coding regions and 16,960 bp from adjacent non-coding regions (5 UTR, 3 UTR and introns). SNPs in coding and non-coding regions occurred at a frequency of 1 per 3,260 bp, corresponding to a nucleotide diversity () of 0.00011, and 1 per 278 bp ( = 0.00128), respectively. This suggested that the higher level of sequence variation in non-coding regions would make them good regions in which to search for SNPs. The SNPs in partial cDNA sequences could be valuable for gene-targeted map construction in soybean.