Three hundred pairs were sampled from a population of D. melanogaster collected from Katsunuma in 1963 and maintained in laboratory. They were selected to both photopositive and photonegative directions during fifteen generations. These two populations responded effectively to the selections, and the realized heritability of both populations for the first 10 generations was estimated similarly to be about 3 per cent.
These populations were relaxed after fifteen generations of selection, and their positive or negative phototactic behaviors were returned to their initial states after only seven generations. This phenomena could be ascribed to the genetic homeostasis formed by the natural selection.
The frequency of deleterious second chromosomes and adult emargence rhythm in these phototactic populations were analysed. The frequency of lethal and semilethal chromosomes in the photopositive population was 43%, and those for the photonegative and the unselected populations were 18% and 27%. The correlation between the frequency of lethal genes and photopositive character was confirmed by the photopositive behavior of lethal heterozygotes (l_i/l_j or l/OR).
Adult emergence rhythm of photonegative flies was not observed even under the periodical light and dark environment (LD 12:12). Mean developmental time (from egg to adult) of photonegative flies was longer than photopositive and unselected flies.

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Isozyme polymorphism of esterase in Oryza sativa L. was investigated with leaves of 776 native varieties collected from known sites of Asian countries by the use of horizontal agar gel thin layer electrophoresis.
The esterase isozymes occurred in altogether fourteen all anodic bands. Of them, nine bands (1A, 2A, 6A, 7A, 10A, 11A, 12A, 13A, 14A) were easily distinguishable and their combination composed 27 different zymograms, indicating the presence of substantially complex variation. Each isozyme differed in its frequency of occurrence in each of the eight areas extended from Sri Lanka to Japan. The bands were grouped into two; one such as 1A and 11A occurred commonly through the areas, the other such as 6A, 7A, 12A and 13A occurred in a distinctive geographic cline.
Zymogram patterns comprising the latter group's bands demonstrated a very conspicuous and sequential geographic cline, terminating in very simple zymograms at both south-and north-most areas of Asia. On the contrary, an area including Nepal, Bhutan, Assam, Burma, Vietnam and Yunnan of China was widest in variation of the zymogram patterns. Consequently, this area was postulated to be the center of genetic diversity in esterase isozymes of O. sativa, proposing an important working hypothesis in advancing researches on its speciation and migration.

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Nuclear DNA content of pollen tetrads of all species of the genus Aegilops were measured microspectrophotometrically.
1) Nine diploid species have a species specific amount of DNA and are divided into a lower or a higher DNA group based on nuclear DNA content. The speciation in Aegilops diploids is associated with a change in DNA content, but not with a change of chromosome number.
2) Significant differences were found among three varieties of Ae. squarrosa.
3) Two tetraploids (Ae. triuncialis and Ae. cylindrica) whose parentage has been confirmed were comparable to the sum of parents in DNA content of the nucleus.
4) No difference between two subspecies of Ae. triuncialis was found, but there was significant difference between Ae. variabilis and Ae. kotschyi which have the same genome constitution.
5) In polyploid species whose diploid ancestors have not been clearly identified, because of modification of the genomes involved, some showed no change, some reduction and still others an increase in DNA content of the nucleus as compared with the putative ancestors.

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The “Ph” agglutinogen was detected in red cells from egg-laying females but not in those from mature males in the BM-C strain. In the tests for the agglutinability of red cells in egg-laying females, the agglutinable strain (BM-C) and the non-agglutinable strain (WL-M) were found. In regard to the agglutinability of embryonic red cells, “Ph” agglutinogen was found in red cells from all embryos tested regardless of sex and strain and it was lost with development of embryos.
Injection experiment of diethylstilbestrol revealed that the estrogen level was essential for the production of agglutinogen. Genetic analysis showed that the production of agglutinogen was controlled by a single autosomal gene. These results indicate the participation of both estrogen and genotype in the production of “Ph” agglutinogen in chick red cells.

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The DNA-modifying and mutagenic activities of N-alkyl homologues of MNNG were investigated by repair tests and mutation tests. All the derivatives tested (i.e., N-methyl-, N-ethyl-, N-propyl-, N-n-butyl-, N-iso-butyl-, N-pentyl- and N-hexyl-N'-nitro-N-nitrosoguanidines) showed DNA modifying and mutagenic activities. In repair test, the ethyl derivative showed the greatest activity on X^s strain. Results in repair test indicated that MNNG might produce X-ray type damage of DNA while homologue with an ethyl substituted or longer chain length might produce UV-type damage in addition to X-ray type damage of DNA.

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Tetra Canthatch, a reconstituted AABB tetraploid, six strains of Aegilops squarrosa and six strains of the synthetic AABBDD hexaploid were compared as to α-amylase isozymes, together with durum reichenbachii and two cultivars of common wheat, Chinese Spring and Canthatch.
Tetra Canthatch and durum reichenbachii showed the same zymogram, with some difference in relative activity of individual bands, which corresponded to the zymogram, in which the bands conditioned by the genes on the D genome chromosomes were removed from that of Canthatch. In addition to Band 1 and 11 which had already been known to be specified by the genes, respectively, on β arm of 6D and on the long arm of 7D, Band 7 was shown to be probably controlled by a gene on β arm of 6D.
Six strains of Ae. squarrosa showed three different zymograms. This means that there is an intraspecific variation, but no variation was found within strains examined Out of total seven bands so far detected in Ae. squarrosa, Band 13 was assumed to be specified by the gene probably allelic to that for Band 11. Band 4, 5 and 7' remain to be genetically defined.
Six strains of Tetra Canthatch-Ae. squarrosa amphiploid showed again three different zymograms, which are the sum of the zymograms of the parents involved. So, zymogram differences among six strains were absolutely attributable to differences among six strains of Ae. Squarrosa involved as the D genome parent of the amphiploid. Three bands on the anodic side, namely, Band 12, 13 and 15 showed more or less enhanced activity in Tetra Canthatch as compared with Canthatch and other hexaploid wheat, while these bands reduced their activity in amphiploids to the degree comparable to Canthatch. This may suggest compensation for missing Band 11 in Tetra Canthatch of the strengthened bands just mentioned.
Two strains of the amphiploid showed the same zymogram as that of Canthatch which is the most prevailing zymogram in hexaploid wheat. Their D genome parents, both belonging to ssp. strangulata evidently carry the same α-amylase genes as those of the D genome of Canthatch.

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