In order to elucidate the origin of tetraploid wheat, nuclear DNA content (1C or 4C) in eight accessions of Triticum urartu, 21 of four Sitopsis species of genus Aegilops and three artificial tetraploids obtained from the F1 hybrid between Ae. longissima, Ae. sharonensis or Ae. bicornis and T. monococcum was measured by means of Feulgen-cytophotometry. T. urartu showed uniform DNA content among the accessions, and was the same DNA as T.monococcum in its DNA content. Some intraspecific variation was noticed in three species, Ae. ongissima, Ae. sharonensis and Ae. searsii. Whereas two other species, Ae. speltoides and Ae. bicornis did not show any significant intraspecific variation. 4C DNA content in three synthesized tetraploids was the same as the sum of the contents of their parents' and was nearly equal to that of Emmer wheat, indicating that all Ae. longissima, _{Ae. sharonensis} and Ae. bicornis can be a candidate of the B genome donor to polyploid wheat. On the other hand, T. urartu and Ae. speltoides have less DNA content than the B genome of polyploid wheat.

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Cytogenetical study on the artificial autotriploid of Oryza glaberrima was carried out.
The reciprocal crosses between the autotetraploid and the diploid were made to produce the autotriploid. Four (0.05%) autotriploids were obtained only by pollinating the autotetraploid with the pollens of the diploid.
As compared with the diploid, the autotriploid increased in stomata length, pollen diameter and length of unhulled and hulled seeds; decreased in number of panicles, pollen stainability, seed fertility and width, thickness and weight of hulled seed. The differences between them were conspicuous in stomata length, pollen diameter, seed fertility and seed weight. The autotriploid had awned spikelets, which was a single character different qualitatively from the diploid. The autotriploid was easily recognized by its seed sterility, but did not show semigigas characteristics so much expected in appearance.
In pollen mother cells of the autotriploid, 5 to 12III were observed at the stage of diakinesis to metaphase I, and 12III most frequently. The mean chromosome configuration was 9.20III+2.68II+3.05I.

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Two novel fourth chromosomal male-determining factors, IV^M, of the housefly were mapped using a modification of the general mapping procedure for autosomal male-determining factors, A^M (Inoue and Hiroyoshi 1984). On the basis of meiotic female recombination frequencies, the same gene order Barl-ye-M was demonstrated for the two IV^M chromosomes. On both chromosomes, male recombination took place although at exceedingly low frequencies. From a comparison between the female and the male recombination maps, it appears that, unlike other A^M factors examined so far, the two IV^M factors are not located near the centromere.

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The ADH isoenzymes were investigated for seeds, seedlings and leaves of mature trees in a tropical tree species, Hopea odorata. The isoenzymes were dimeric and controlled by two loci;Adh 1 consisted of 3 alleles designated asAdh 1S, Adh 1N andAdh 1F, andAdh 2 was isoallelic. A differential gene expression of these loci was described. With use ofAdh 1 as a genetic marker outbreeding rate (t=0.634), interpopulational pollen flow rate (u =0.315) and selection coefficient for N/N genotype (s=0.486) were estimated in an experimental plantation consisting of two separate stands; S/S, S/N and N/N genotypes growing at Site I and S/S, S/F and F/F genotypes at Site II.

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To evaluate genetic variability within and between populations of two closely related snail species Semisulcospira libertina and Semisulcospira reiniana, enzymes coded for by 18 presumed loci were examined by starch gel electrophoresis.
The proportion of polymorphic loci and the expected average heterozygosity per individual for the S. libertina populations were 0.172 and 0.057, respectively. These for the S. reiniana populations were 0.114 and 0.039, respectively. Nei′s genetic distance value estimated between the two species was 0.1235.
Marked difference in allele frequency between the two species was observed at the MPI and 6PGD loci. Other five loci (ICDH-1, AAT, MDH-1, PHI and Est) were variable in some of the libertina populations, although the five loci were fixed for the wild type allele in all of the reiniana populations. Another locus PGM-1 was variable in both species. These loci seemed to be useful genetical markers for differentiating S, libertina from S. reiniana.

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Development of the germline cells of P-M dysgenic hybrids causing Gonadal (GD) sterility in Drosophila melanogaster was analyzed using light and electron microscopes. The first indication of an abnormality appeared in pole cells (primordial germ cells) during migration to gonadal mesoderm 5 to 6hr at 29°C. This stage corresponds to the initial stage of the temperature sensitivity of GD sterility. Necrosis of primordial germ cells was prominent in the gonads at the first instar when the primordial germ cells undergo exponential mitotic proliferation in normal larvae. About 10% of primordial germ cells degenerated in nearly all the gonads of the first instar larvae which would normally develop into fertile flies at 25°C.

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Restriction endonuclease analysis was carried out on the chloroplast (ct) DNA of 11 species belonging to three subgenera of genus Prunus which includes most common flower trees in Japan, namely, "Sakura" (P, yedoensis and others) and "Ume" (P, mume). The ctDNA isolated from fresh leaves was digested with three endonucleases, BamHI, HindIII, and SmaI, and electrophoresed using agarose slab gel. The ctDNAs of the three subgenera had different restriction fragment patterns. In the subgenus Cerasus, two ctDNA types were found, one type in P. yedoensis and P, pendula, and the other in P. lannesiana, P, apetana, P. verecunda and P. sargentii. Similarly, four ctDNA types were found in the subgenus Padus, each type in P. buergeriana, P. grayana, P. Padus and P. ssiori. The ctDNA of the only one species, P, mume, in the subgenus Armeniaca studied differed from those of any of the other species. Chloroplast genome sizes of these species were estimated to be about 140kbp. Based on the present restriction data, two dendrograms showing genetic relatedness between chloroplast genomes of 11 Prunus species were constructed. P, yedoensis, the most common cultivar of the flower cherry, which is presumably a natural hybrid between P. pendula and P, lannesiana (Takenaka 1963) showed no interplant variation of ctDNA and had the same ctDNA as the former species, differing from the latter by a single HindIIl restriction site. This finding suggests that P. pendula is the female parent of P. yedoensis.

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The cytoplasmic 5S ribosomal RNA (rRNA) sequences from seven red algae, a golden-yellow alga, a diatom and five brown algae have been determined. Using these sequences, phylogenic tree of these organisms have been constructed.
Three types of algae, i.e., Rhodophyta (red algae), green algae (members of green plants), and Chromophyta (brown algae, the diatom and the goldenyellow alga) are only remotely related to one another phylogenically as deduced from the 5S rRNA sequences. Red algae emerged first in the eukaryotec evolution (1.3 to 1.4 billion years ago), and thereafter various fungi, green plants including green algae and Chromophyta emerged in this order. In the red algal evolution, the so-called "primitive group" of the class Bangiophyceae and "more advanced group" of the class Florideophyceae separated first from each other in an early stage of their evolution. The tree also indicates that various red algae, such as Batrachospermum, Gelidium, Gloiopeltis and Carpopeltis are phylogenically rather remote from one another. Thus, red algae are very widely and anciently separated organisms in the evolution of eukaryotes.
Chromophyta contains golden-yellow algae, diatoms and brown algae. These three groups are related to one another. During the Chromophyta evolution, the golden-yellow alga separated first, and thereafter the diatom and brown algae separated from each other. Although brown algae are very different in their morphology and life cycle, the 5S rRNA sequences clearly indicate that the brown algae were diversified quite recently within a short period.

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A horned goat with testicular hypoplasia was examined cytogenetically. A total of 72 cells were analyzed, 62 of which had an extra X chromosome (2n=61, XXY) and 10 of which had a male karyotype (2n=60, XY). We propose the hypothesis that, in this case, testicular hypoplasia may have been related to mosaicism of the sex chromosomes.

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