In order to clarify the phylogenetic relationships in A-genome species of rice, RAPD analysis was carried out using 29 accessions (8 Oryza sativa, 6 O. glaberrima, 13 O. perennis, and 2 O. breviligulata). Their total DNA was used as template for PCR with 14 decamer primers. The amplified products were electrophoresed in agarose gel, and the banding patterns were observed. Average number of total amplified bands for each accession using 14 primers was 84.6. By comparing the banding patterns, the proportion of common bands between 29 accessions was calculated and a dendrogram showing genetic relationships was constructed. Most of the accessions formed clusters corresponding to their taxonomic grouping. The Oceanian and African forms of O. perennis were substantially different from all other groups. The Asian form of O. perennis, however, formed a complex with O. sativa while O. breviligulata was clustered with O. glaberrima. This indicates that O. sativa and O. glaberrima have probably originated from the Asian form of O. perennis and from O. breviligulata, respectively.
The family Temnopleuridae of the order Echinoida from Japanese waters is represented by the four echinoid species belonging to the two different genera: Temnopleurus toreumaticus, T. hardwickii, T. reevesii, and Mespilia globulus. Their phylogenetic relationships were investigated by electrophoretic analyses of 16 different enzymes. From the allozyme variation in 30 genetic loci, the Nei's genetic distances between species were caluculated and the molecular phylogenetic tree for the four species was constructed. The phylogenetic tree indicated the following: (1) Among four species of the family, T. toreumaticus and T. reevesii are the most closely related to each other and diverged later. (2) T. hardwickii is more genetically differentiated from the other two congeners. (3) M. globulus is the most distant species of the four members. These allozyme results were discussed through the comparison with other non-molecular evidence, and the divergence process of the four echinoid species was speculated.
Diffusion routes of common buckwheat were investigated by constructing phylogenetic trees based on variability of RAPD markers among 46 land races and two natural populations of the ancestor. Thirty two primers out of 40 generated reliable RAPD bands, 295 in total. The percentage of polymorphic bands was the highest (45.9%) in southern China, the region in which buckwheat originated, and it declined sharply from southern China to the peripheral range of buckwheat cultivation. Phylogenetic trees for land races were constructed from RAPD variability by the unweighted pair group (UPG) and neighbors joining (NJ) methods. They suggest two major routes of diffusion of buckwheat cultivation; one from southern China → northern China → Korea → Jpan, the other from southern China → Bhutan → Nepal → Kashmir → Karakoram and the Hindukush.
Four species of Fagopyrum, two species of Persicaria and one species of Rumex were analyzed for the DNA sequences of their rbcL genes. In addition to these seven species, we analyzed the published or available sequence data of ten related taxa in Polygonales, Plumbaginales and Caryophyllales. By estimating the base substitution rate between each pair of species, and by constructing phylogenetic trees we concluded that: 1) In Fagopyrum, F. cymosum and F. tataricum are much more closely related than expected previously; this confirms the conclusion of Kishima et al. (1995). 2) The new classification of Fagopyrum species proposed by Ohnishi and Matsuoka (1996) based on morphology, isozyme and cpDNA variability is consistent with the rbcL sequences. 3) The Polygonales and the Plumbaginales should be separated from the Caryophyllales as concluded by Giannasi et al. (1992). 4) The separation of Fagopyrum from other genera in the Polygoneae has a solid molecular basis.
Haploid liverwort Conocephalum conicum is known to be composed of several types (C, A, L, S, J, T and FS). The level of genetic variability of C. conicum was surveyed using starch gel electophoresis at putative18 enzyme loci from 7 natural populations in Kyushu, Kanto and Tohoku districts. We found two new types which were different not only from either FS or T type, but also from J type in isozyme band patterns, and named them YFS and KYT type. The average heterozygosities of J type from several populations in Kyushu district and Goyosan in Tohoku district were 0.142 and 0.163, respectively. Those of FS and T types from Takaosan in Kanto district, YFS and KYT type from Yakiyama in Kyushu district were 0.146, 0.104, 0.263 and 0.240, respectively. A parameter of genetic differentiation between populations (Gst) of the J type were 0.045. This study has confirmed the previous results that the high levels of genetic variability are maintained in natural populations of Kyushu district. High level of genetic variability and low genetic differentiation of Kyushu populations in this haploid plant as well as the data showing high level of Gst among the geographically distant populations in various parts of Japan may be explained by the hypothesis that the dominant factor determining the genetic structures of this liverwort is random genetic drift with little migration between different regions of Japan. The finding of various types of C. conicum in Japaneses populations together with the clear difference in isozyme patterns between types supports the idea that these types are different biological species.
We observed novel phenomena on the growth of a hemA deletion mutant (H500) of Escherichia coli: First, H500 cells grown in rich medium required an increased amount of exogenous 5-aminolevulinic acid (ALA) for normal growth, as compared with cells grown in poor medium. Second, H500 cells grown with an insufficient supply of ALA had a prolonged lag phase but relatively normal growth during the logarithmic phase. An increased requirement of exogenous ALA in rich media was due to an impermeability of the cells to ALA, resulting in a reduced ability to synthesize porphyrins. The latter could be also explained by change in permeability that was repressed under heme-deficient conditions.
A chromosome derived from Aegilops cylindrica (2n=4x=28, genomically CCDD) causes chromosome breakage in the gametes lacking the alien chromosome in a common wheat (Triticum aestivum, 2n=6x=42, AABBDD) cv. Chinese Spring. The Ae. cylindrica chromosome was studied by monosomic analysis and demonstrated to successfully substitute for chromosomes 2A, 2B, and 2D in the disomic condition. From its morphology and C-banding pattern, the Ae. cylindrica chromosome was assumed to have been originated from the C genome. Therefore, the present author proposed to designate this alien chromosome as 2C. During this study, a telosome of the long arm, an isochromosome of the long arm, and a deletion in the long arm of the Ae. cylindrica chromosome were obtained. Their abilities of inducing chromosome breakage suggested that a gene responsible for the chromosome breakage was located on the distal half of the long arm of the alien chromosome.
A recessive mutation, hiiragiP1, on the second chromosome of Drosophila was obtained by P element insertion mutagenesis. Flies homozygous for hiiragiP1 have notched wing margins. Genetic interactions between hiiragi and the genes that encode components of Notch signaling, such as Notch, Hairless, Serrate and deltex, strongly support the involvement of hiiragi in the signal transduction cascade of Notch. It has been reported that Serrate and Delta, other components of Notch signaling, share EGF-like repeats and a second conserved cysteine-rich motif, and that these components interact physically with the same region of Notch. In hiiragiP1; SerrateD/+ double mutants, we observed synergistic enhancement of the notched phenotype of wing margins. In contrast, DeltaFX3 had no phenotypic effect on hiiragiP1 in hiiragiP1; DeltaFX3/+ double mutants. Taken together, these results indicate that hiiragi is involved in the Notch signaling cascade induced by Serrate rather than by Delta.
We have identified three strains of the same S24-haplotype in self-incompatible B. campestris L. Two of them, S-12j and 1-1j, have been derived from Japanese populations and one, 27-1t, from Turkish one. The cDNA clones of SLG24 (S24-locus glycoprotein), which linked to the S-locus, were isolated from each strain, and sequenced. Each clone isolated from S-12j, 1-1j and 27-1t, was designated as SLG24 (S-12j), SLG24 (1-1j) and SLG24 (27-1t), respectively. Their nucleotide sequences were completely identical in coding region, 5' non-coding region, and 3' non-coding region, though the position of the polyadenylation site was slightly different among the cDNA clones. This result suggests that the origin of S24-haplotype in these three strains might be common, and that the nucleotide sequences of SLG24 of the same S24-haplotype are completely conserved among different populations. The high conservation of the SLG24 nucleotide sequences is probably essential for the recognition of self or non-self of self-incompatibility in this S24-haplotype.