Thirty-six potato cultivars released in Japan and three introduced cultivars were characterized by random amplified polymorphic DNA (RAPD) assay. The RAPD patterns were highly reproducible and identical using DNA samples obtained from different locations and tissues (leaf or sprout). Five decamer primers amplified 15 useful DNA segments which were polymorphic and shared among the cultivars. By the presence or absence of these RAPDs, all of the cultivars were clearly identified. Description of cultivar identities by RAPDs is suggested for cultivar registration and in germplasm maintenance program.
Nuclear retinoic acid receptors RARα, RARβ and RARγ are transcription factors that bind all-trans retinoic acid as their ligand and mediate its action by activating particular set of genes that contain retinoic acid responsive elements in their promoter-enhancers. We have mapped genetic loci for these genes using restriction fragment length variants (RFLVs) in interspecific backcross mice. None of the Rar loci cosegregated with each other or with the new subclass of retinoid receptors, Rxr loci. Rara mapped to mChr 11, Rarb mapped to mChr 14, and Rarg mapped to mChr 15. The results are consistent with the previous reports and the human data in terms of syntenic homology between mouse and human chromosomes.
Endoreduplication was induced by rotenone with an extremely high frequency (approximately 90% of all the metaphases) in cultured Chinese hamster cells. Endoreduplicated cells were fixed without colchicine or hypotonic treatment, and chromosomal configurations were examined in various mitotic stages. The two sister chromosomes of each diplochromosome at late prophase were widely separated except the centromeric region, but they became gradually paired along the total length as the cell cycle progressed to metaphase. The anaphase cells underwent multipolar division, resulting in three or four aneuploid daughter cells. Indirect immunofluorescence staining using anti-β tubulin antibody revealed tripolar or tetrapolar spindles and unusual equatorial plates.
Cloned sequences of three retrotransposons of rice, Tos1-1, Tos2-1 and Tos3-1, were used as molecular genetic markers to distinguish the cultivars of Asian and African rice, Oryza sativa and Oryza glaberrima. DNAs of six cultivars each of Indica and Japonica types of O. sativa were analyzed after digestion with four different restriction enzymes. Indica cultivars could be distinguished from each other by any of three types of one probe-one restriction enzyme combination. Although the hybridization patterns were similar among Japonica cultivars, these cultivars could be distinguished from each other by one type of one probe-one enzyme combination. Five cultivars of O. glaberrima examined were also distinguished from each other by using one probe-one enzyme combination. The results shown here indicate that retrotransposon-mediated fingerprinting is an efficient method to distinguish or identify the cultivars of rice. Retrotransposonmediated fingerprinting should become a general method, because retrotransposons are ubiquitous in plant species and retrotransposon probes can easily be obtained from any plant species.
We analyzed the presence of p-SINE1 members at five loci in the rice strains belonging to seven species with AA genome in the Oryza genus by the methods including polymerase chain reaction (PCR). Four p-SINE1 members (p-SINE1-r3, r4, r5 and r7) were present at the corresponding loci in all the strains examined. One member (p-SINE1-r6) was, however, not present at the corresponding locus in most of the African strains of O. glaberrima and O. barthii, but was in the other strains. The PCR-amplified fragments containing p-SINE1-r4 in many strains were found to be larger due to insertion of either one of two transposable elements, named Tnr2 and Ret1, within or near p-SINE1-r4, respectively: Tnr2 is 157 bp in length with terminal inverted repeat sequences of about 56bp; Ret1 is only 13 bp in length with a T stretch at its end. Tnr2 was not present in the corresponding locus in all the strains belonging to O. sativa Japonica and in some strains of O. rufipogon and O. longistaminata, while Ret1 was present only in the two strains of O. longistaminata. These results and previous ones obtained from the analysis of the other two p-SINE1 members (p-SINE1-r1 and r2) in the Wx gene indicate that the elements, such as p-SINE1r6, Tnr2, Ret1 and p-SINE1-r2, have been inserted into the respective loci during divergence of the rice species with AA genome. The patterns for the presence and absence of the transposable elements at the respective loci enabled us to classify the rice strains with AA genome into ten groups and to infer their relationships.
Electrophoretic variations of prophenoloxidase were obtained from natural populations of Drosophila melanogaster. A1, one of the 2 isofojrms of the prophenoloxidases, is polymorphic: 10 fast-migrating and 2 slow-migrating types were found in polyacrylamide gel electrophoresis among 271 wild strains. The majority were the intermediate-migrating type. By use of these variants, A1 gene was mapped at 79.6 on the right arm of the second chromosome. By deletion mapping, its cytological position was located at 55A-B. In the electropherograms, hybrids between the types differing in mobility exhibited 3 bands, indicating that A1 is a dimeric protein. The gene for A1 is expressed through larval, pupal and adult stages.
Two major protein groups of taro (Colocasia esculenta) tuber were purified, and their antisera were used for the screening of the cDNA library constructed from poly(A)+ RNA of taro tuber. A cDNA clone obtained by screening with an anti-12 kD protein antiserum had an insert 1058 bp-long, and an open reading frame for a peptide of 268 amino acids. The analyses of the N-terminal amino acid sequence and in vitro translation product suggested that the protein was synthesized as a peptide with a molecular weight of 27 kD, and then processed into two mature peptides with a molecular weight of 12.5 and 13.9kD and an extra peptide with a molecular weight of 0.6kD. The cDNA clones obtained using the anti-25 kD protein antiserum were highly homologous with each other. One of them had an insert 958 bp-long and an open reading frame for a peptide with 209 amino acids. The amino acid sequence deduced from the nucleotide sequence of this clone indicated that the 25 kD proteins were homologous to the trypsin inhibitors of soybean and winged bean as well as sporamins, the storage proteins of sweet potato.