著者

Hideki INNAN Ryohei TERAUCHI Naohiko T. MIYASHITA Koichiro TSUNEWAKI

出版者

The Genetics Society of Japan

雑誌

遺伝学雑誌 (ISSN:0021504X)

巻号頁・発行日

vol.70, no.2, pp.185-196, 1995 (Released:2004-06-08)

参考文献数

22

被引用文献数

19 35

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In order to investigate the intraspecific variation of Prunus yedoensis (Someiyoshino) and interspecific relationship among P. yedoensis, P. lannesiana (Oshimazakura) and P. pendula (Edohigan), DNA fingerprinting study was conducted by using two different kinds of probes, M13 repeat sequence and (GACA)4 synthetic oligonucleotide. In this study, 68 plants of P. yedoensis grown in 46 prefectures in Japan were investigated. All the P. yedoensis individuals investigated showed the completely same banding pattern, indicating their clonal origin from a single plant. On the other hand, each of P. lannesiana and P. pendula individuals investigated showed a unique banding pattern, suggesting a considerable amount of genetic variation in these two species. About 90% of bands in DNA fingerprints of P. yedoensis were detected in either P. lannesiana or P. pendula. This result supports the hypothesis that P. yedoensis is an interspecific hybrid between P. lannesiana and P. pendula. From those results, it is concluded that P. yedoensis was produced only once through hybridization between P. lannesiana and P. pendula, and that this particular hybrid plant has been spread vegetatively all over Japan.

著者

田島 弥太郎

出版者

日本遺伝学会

雑誌

遺伝学雑誌 (ISSN:0021504X)

巻号頁・発行日

vol.47, no.5, pp.313-314, 1972 (Released:2007-05-21)

著者

SADAO ICHIKAWA

出版者

日本遺伝学会

雑誌

遺伝学雑誌 (ISSN:0021504X)

巻号頁・発行日

vol.47, no.6, pp.411-421, 1972 (Released:2007-05-21)

参考文献数

12

被引用文献数

13 12

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Somatic mutation rates from blue to pink were studied in the stamen hairs of Tradescantia ohiensis KU 7 clone, a blue/pink heterozygote, exposed to 100 to 510mR/hr gamma rays or to 12mR/hr scattering radiation. The results obtained supported the previous finding of the sensitive genetic responses of this botanical system, demonstrating that the genetic effect could be detected with this system at a radiation level as low as 3.60R total exposure (also possibly only 0.96R) given at a low exposure rate of 12mR/hr. Pooling the present and previous data, a somatic mutation rate of 3.88 or 3.43×10-4 pink mutant events per hair per R was obtained for gamma-ray irradiation during hair development. The somatic mutation rate calculated for scattering radiation was even higher than this (1.25×10-3). The doubling dose of the somatic mutations at the specific locus was calculated to be 13.8 or 15.6R when irradiated with gamma rays during hair development, and the corresponding value with scattering radiation was 4.29R. Lower doubling doses could be calculated based on published data from the stamen hairs of the same and three other Tradescantia clones irradiated more acutely. These low doubling doses seem to throw doubt on the safety standards of radiations.

著者

Marie SANDA-KAMIGAWARA Michio TOMIYAMA Sadao ICHIKAWA

出版者

日本遺伝学会

雑誌

遺伝学雑誌 (ISSN:0021504X)

巻号頁・発行日

vol.70, no.3, pp.339-353, 1995 (Released:2004-06-24)

参考文献数

29

被引用文献数

8 10

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The sectoring patterns of spontaneous and radiation- and EMS-induced somatic pink mutations were analyzed in the stamen hairs and petals of Tradescantia clones heterozygous for flower color (blue/pink). Spontaneous pink mutations were analyzed using clone KU 20 (a highly mutable clone especially at lower temperature) grown outdoors and clones KU 27 and BNL 02 (stable clones) grown under controlled environmental conditions, while induced pink mutations were analyzed using clones KU 27 and BNL 02 grown under the controlled environments. As for spontaneous mutations in the stamen hairs, the ratio of the number of single interstitial pink mutant events against that of single terminal pink mutant events was somewhat larger than 1 in all the three clones examined, indicating that somewhat more interstitial pink mutant events occur spontaneously than terminal pink mutant events. After treatments with X rays, gamma rays or EMS, however, the ratio increased to about 3 in the two clones examined, showing much more frequent inductions of interstitial pink mutant events than terminal pink mutant events by these mutagens. The daily changes of the sectoring patterns of radiation- and EMS-induced terminal pink mutant events in the stamen hairs showed a good accordance with the pattern of the stamen-hair development. Multiple pink mutant sectors in the same hairs were observed at much higher frequencies than expected from independent occurrences, especially in cases of spontaneous mutations in the mutable clone and of radiation-induced mutations in the two stable clones, suggesting the involvement of somatic recombinations. The sectoring patterns of radiation- and EMS-induced somatic pink mutations in the petals also showed daily changes which reflected the pattern of the flower-petal development.

著者

木村 資生

出版者

日本遺伝学会

雑誌

遺伝学雑誌 (ISSN:0021504X)

巻号頁・発行日

vol.35, no.1, pp.7-33, 1960 (Released:2007-05-21)

参考文献数

24

被引用文献数

6 12

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1. Definition of genetic load: Genetic load of a population in CROW'S sense (CROW 1958) refers to the amount by which population fitness is decreased through natural selection acting on genotypic differences. It may either be expressed in terms of selective values or Malthusian parameters depending on whether the continuous or discrete model is used to describe generation time (cf. KIMURA 1958).2. Kinds of genetic load: (i) Mutational load results from elimination of harmful mutations. (ii) Segregational load arises when heterotic genes (overdominance load) or a meiotic drive mechanism (distortional load) is involved. (iii) Dysmetric load, term proposed by HALDANE (unpublished), refers to a load which may be created when there is a “division of labor” between genotypes. (iv) Internal vrs. external load; The former refers to the decrease of fitness relative to the optimum genotype and thus relates to intragroup selection, while the latter refers to that relative to the optimum condition and therefore relates to intergroup selection. (v) Substitutional (evolutional load) is a cost of natural selection (cf. HALDANE, 1957) which is required in the process of substituting one allele by another through natural selection.3. Principle of minimum genetic load: This is a hypothesis that in the course of evolution important genetic parameters tend to be adjusted in such direction that the total genetic load will be minimized. More specifically, the spontaneous mutation rate and degree of dominance of mutant genes may be adjusted such that the sum of the mutational and the segregational loadL=Lm+Lewill be minimized. From this principle, the following relations may be derived (KIMURA, 1959):∑μ=0.3419E/h(1+0.3679h+…)h=0.6838√<E/2D>(1+0.0934√<E/2D>+…), where ∑μ is the spontaneous mutation rate per gamete per generation, h is the average degree (harmonic mean) of dominance in fitness of deleterious mutant genes, D is the total mutational damage or approximately the rate of inbreeding depression in fitness per unit increase in the inbreeding coefficient and E is the rate of substituion of genes in horotelic evolution (standard rate evolution, cf. SIMPSON 1944).Taking E=1/300 (cf. HALDANE 1957) and D=2 (cf. MORTON, CROW and MULLER 1956), we obtain from the above equations, h=0.0196 and ∑μ=0.0585, which agree fairly well with the corresponding observed values in Drosophila. With these values, mutational and substitutional loads (in terms of Malthusian parameters) become respectivelyLm=0.098 and Le=0.199.4. Accumulation of genetic information by natural selection: It was pointed out that the rate of accumulation of genetic information (H) by natural selection is directly proportional to the substitutional load Le, namelyH=Le/loge2≈1.44Le (bits/generation).With Le=0.199, the value obtained above, this becomes about 0.29 bits;H≈0.29.It was estimated then that the total amount of genetic information accumulated since the beginning of Cambrian epoch (500 million years) may be of the order of 108 bits, if evolution proceeded at the standard rate.Since the genetic information is transformed into phenotypic information in ontogeny, this figure (108 bits) must represent the amount of information which corresponds to the improved organization of higher animals as compared to their ancestors 500 million years back. It may also be interesting to compare this figure with the one (107_??_109 bits) obtained by ELSASSER (1958) as the probable “information content of the human organism”.

著者

SADAO ICHIKAWA ICHIZO NISHIYAMA

出版者

日本遺伝学会

雑誌

遺伝学雑誌 (ISSN:0021504X)

巻号頁・発行日

vol.42, no.3, pp.175-187, 1967 (Released:2007-05-21)

参考文献数

36

被引用文献数

2 2

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Dry seeds of a Japanese variety of common wheat (6x), Shinchunaga, were irradiated with 10 to 40 kR of gamma rays from 60Co. No chlorophyll mutations were detected, while various kinds of morphological mutants were found in the X2 through X8 generations. About one third of the morphological mutants were found in the X2, another third in the X3, and the remaining third in the later generations.The lack of any chlorophyll mutation and the frequent occurrence of various morphological mutations are considered to indicate that there is a difference in the extent of differentiation in this polyploid plant between essential genes such as those for chlorophyll production and non-essential genes such as those determining spike length or density.Many speltoid, compactoid, squareheaded, lax-spiked and dense-spiked mutants were found, as well as various other mutants. Cytogenetical investigations were performed on these morphological mutants, and it was found that most of these morphological mutants were caused by various chromosomal aberrations, such as deficiencies, telocentrics, isochromosomes, and various aneuploid constitutions.

著者

小野 記彦

出版者

日本遺伝学会

雑誌

遺伝学雑誌 (ISSN:0021504X)

巻号頁・発行日

vol.30, no.6, pp.269-274, 1955 (Released:2007-05-21)

参考文献数

4

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1. ヤクシソウとワダンとの雑種は自然に存在するヤクシワダンとよばれるものもあるが, 人工的につくつた雑種もだいたいこれと同じものになる.2. この雑種の減数分裂における対合は特異であり, 染色体形態の異るにもかかわらず, 常に 5IIがみられる. その子孫においては染色体の配分がいろいろとみだされるが, 中期では5個の Configurationsを示すものがもつとも多く見られた. しかしより早い時期では, Configurations の数の減少, すなわち多価染色体が多く見られた. このようにはじめに結合していて中期に進むにつれて解消するような結合を残余対合 (residual pairing) とよんだ.3. 自然雑種は新しい種の出発点となり得るかどうかはいろいろの考えがあるが, 属間雑種のように両親の形質が遠いものでは, 二次的安定種がつくられる可能性が示された.4. ヤクシソウとアキノノゲシとの雑種では染色体数が一定しないで 10~14 のいろいろの数の細胞が一つの根においてもキメラになつているのがみとめられた. しかしその中で12のものが, もつとも多く, しかも得られた9個体において, このことは常に一定であつた.5. 同じような染色体の分断消失による減少はヤクシソウとアゼトウナとの雑種, ワダンとアキノノゲシとの雑種においても見出される. しかもいつでも分断消失する染色体は父方のものである.6. 自然にもこのような雑種がみられるが, アゼトウナ自然集団の中から採集された自然雑種においても同じように染色体の分断消失がみられる.7. 自然集団の中には 90% 以上の高い稔性のもののみの集団と 20% ぐらいのひくい稔性のものをふくむ集団とがある. 前者は古くできた雑種集団であり, 後者は新しくできた雑種のふくまれる集団であると思われる.

著者

佐野 順一 田中 正武

出版者

Genetics Society of Japan

雑誌

遺伝学雑誌 (ISSN:0021504X)

巻号頁・発行日

vol.55, no.1, pp.9-17, 1980

被引用文献数

3

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In order to estimate chromosomal homology between <i>Aegilops</i> <i>speltoides</i> (genomic constitution SS) and the tetraploid wheats (AABB or AAGG), effects of the B-chromosomes and genotypes of <i>Ae. speltoides</i> on chromosome pairing at MI of meiosis in F₁ hybrids of <i>Ae. speltoides</i> × tetraploid wheats were investigated.<br>In hybrids with B's, chromosome pairing was strikingly affected by the B's and very small amount of pairing was observed. In hybrids without B's, however, extensive pairing was observed, although the amount of pairing varied due to the <i>speltoides</i> genotypes involved. In these hybrids with or without B's, although some minor yet distinctive differences in pairing attributable to the kind of genomic constitution of the wheat parent were observed in the multivalent frequency and in the distribution (or terminalization) of chiasmata, both hybrids with different genomic constitution (SAB or SAG) had essentially the same amount of pairing. Since the B-chromosomes used did not cause asynapsis (or desynapsis) of homologous chromosomes in <i>Ae. speltoides</i>, the pairing reduced by the presence of B's in the hybrids does not seem to be homologous and is probably homoeologous. Therefore, it can be concluded that there is little chromosomal homology between <i>Ae. speltoides</i> and both tetraploid wheats of genomic constitution AABB and AAGG.

著者

庄武 孝義 野沢 謙 田名部 雄一

出版者

Genetics Society of Japan

雑誌

遺伝学雑誌 (ISSN:0021504X)

巻号頁・発行日

vol.52, no.3, pp.223-237, 1977

被引用文献数

35

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In central Ethiopia the hamadryas baboon, <i>Papio hamadryas</i> and the anubis baboons, <i>Papio anubis</i>, have been hybridizing naturally. Studies were made by using electrophoretical blood protein variations as markers in order to clarify the genetic interrelationships between them. A total of 414 individuals belonging to 7 populations were examined for 35 blood protein loci. Eleven of 35 loci showed polymorphism. The Tf locus was found to have the strongest power for discriminating between the anubis and the hamadryas. The results of our genetic survey revealed that most of the populations from which we collected blood samples were more or less hybridized. The Nei's (1975) genetic distance between the two species was estimated to be at most as 0.0674. As this value was too small to consider these species as real biological species, we think that the natural hybrid zone is fairly wide and still expanding now.

著者

星野 安咨

出版者

日本遺伝学会

雑誌

遺伝学雑誌 (ISSN:0021504X)

巻号頁・発行日

vol.16, no.4, pp.155-163, 1940 (Released:2007-04-04)

参考文献数

4

被引用文献数

3

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In this report two more rare pattern types: aulica (Fig. 1-a, b) and gutta (new name proposed by Prof. T. Komai) (Fig. 1-f, g, h) are dealt with. Both of these are due to the factors (PAu=factor for aulica, PG=factor for gutta) belonging to the same allelomorphic series as conspicua, transversifascia, spectabilis, axyridis, forficula and succinea and behave as dominants to succinea.The heterozygote of axyridis and aulica (PAPAu) (Fig. 1-c) and the heterozygote of forficula and aulica (PFPAu) (Fig. 1-d) can be distinguished as such from homozygotes. The heterozygote of transversifascia and aulica (PTPAu) may be distinguished from transversifascia in that the spot has a concavity on the antero-median side (Fig. 1-e), though in some cases the heterozygote of transversifascia and aulica shows the same appenrance as transversifascia. The distinction between the heterozygote of gutta and axyridis (PGPA) and the heterozygote of conspicus and axridis (PCPA) and that between the heterozygote of gutta and forficula (PGPF) and the heterozygote of conspicua and forficula (PCPF) can often made by the fact that the spot is provided with an accessory speck on its antero-median corner, though the speck may be missing in some cases (see Report II, Fig. 1-l, m and Report III, Fig. 1-e). The heterozygote of conspicua and aulica (PCPAu), the heterozygote of conspicua and gutta (PCPG), the heterozygote of gutta and spectabilis (PGPS), the heterozygote of gutta and transversifascia (PGPT) and the heterozygote of gutta and aulica (PGPAu) can not be distinguished from conspicua; the heterozygote of spectabilis and aulica (PSPAu) may shows the same appearance as spectabilis.

著者

Masami HASEGAWA

出版者

日本遺伝学会

雑誌

遺伝学雑誌 (ISSN:0021504X)

巻号頁・発行日

vol.65, no.4, pp.243-266, 1990 (Released:2006-06-10)

参考文献数

85

被引用文献数

11 21

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Statistical methods for estimating the branching order and the branching dates from DNA sequence data, taking into account of the rate variation among lineages, are reviewed. An application of the methods to data from primates suggests that chimpanzee is the closest relative of man, and further suggests that these two species diverged about 4-5 million years ago.

著者

TSUNEWAKI K. KASAHARA F. FUJITA T.

出版者

Genetics Society of Japan

雑誌

遺伝学雑誌 (ISSN:0021504X)

巻号頁・発行日

vol.46, no.2, pp.103-107, 1971

被引用文献数

2 4 6

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One hundred and eighty-nine Chinese cultivars of common wheat were crossed to three testers for necrosis and chlorosis genes, and their genotypes were determined. <br>Three genotypes, <i>Ne</i>₁<i>ne</i>₂, <i>ne</i>₁<i>Ne</i>₂ and <i>ne</i>₁<i>ne</i>₂ for necrosis were found in 39.3, 7.1 and 53.6% of the cultivars, respectively. As to chlorosis genes, the great majority of cultivars (93.4%) were of the genotype, <i>ch</i>₁<i>Ch</i>₂, the remainder (6.6%) were <i>ch</i>₁<i>ch</i>₂. It was evident that common wheat retained its characteristic population structure regarding necrosis and chlorosis during its eastward dispersion from Central Asia to Japan through China. No particular geographical inclination in the frequencies of various necrosis and chlorosis genotypes, nor their special association with the two characters, growth habit and awnedness, was detected.

著者

禹 長春

出版者

The Genetics Society of Japan

雑誌

遺伝学雑誌 (ISSN:0021504X)

巻号頁・発行日

vol.6, no.3, pp.205-205, 1930

著者

禹 長春

出版者

The Genetics Society of Japan

雑誌

遺伝学雑誌 (ISSN:0021504X)

巻号頁・発行日

vol.1, no.2, pp.101-106, 1922

著者

芳賀 〓

出版者

日本遺伝学会

雑誌

遺伝学雑誌 (ISSN:0021504X)

巻号頁・発行日

vol.29, no.5-6, pp.228-234, 1954 (Released:2007-11-30)

参考文献数

20

被引用文献数

3 1

著者

TOSIHIDE H. YOSIDA CHOJI TAYA

出版者

The Genetics Society of Japan

雑誌

遺伝学雑誌 (ISSN:0021504X)

巻号頁・発行日

vol.52, no.4, pp.289-299, 1977 (Released:2007-05-21)

参考文献数

46

被引用文献数

6 2

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Semen of the black rat was inseminated artificially into the female Norway rat by routine technique. Among 20 rats, 9 showed pregnancy. Five impregnanted rats were dissected on 8 to 14 days after insemination and one to 4 embryos were found. No offspring were born in the case of the artificial insemination. In the control in which the semen of the Norway rat was inseminated artificially into the female Norway rat, pregnancies were obtained at high frequency and offspring were successfully born as in natural matings. Chromosomes of the hybrid blastocysts showed 42 chromosomes consisting of two haploid sets, one from the Norway rat and the other from the black rat.

著者

平井 久男

出版者

日本遺伝学会

雑誌

遺伝学雑誌 (ISSN:0021504X)

巻号頁・発行日

vol.31, no.2, pp.54-64, 1956 (Released:2007-05-21)

参考文献数

84

被引用文献数

4 4

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脉翅目のヒロバカゲロウ上科 (Osmyloidea) に属する3科9種の染色体研究を行い, 系統的関係について論及した. 染色体数, 性染色体の型は Table 1 に示した通りである.カマキリモドキ科 (Mantispidae) においては1対の巨大な常染色体が存在し, これがこの科の特徴となつている.ミズカゲロウ (Sisyra japonica) のX-Y染色体の第一分裂における先行現象は他種の場合に比し著しくない. ツマモンヒロバカゲロウ (Plethosmylus decoratus) は X1 X2-Y 型の複合性染色体をもつている.X-Y染色体の行動を成長期の核内に追求した. XとYとは肥厚期 (diakinesis) の時期にすでに接合をといて分離していることがたしかめられた. 細長期 (leptotene) から合体期 (pachytene) にかけてX-Y染色体は異常凝縮をなした3部構造をしているが, 二重期(diplotene) になると染色性が一時弱まり, 肥厚期 (diakinesis) に入つてXとYとは分離する.

著者

岸本 艶

出版者

日本遺伝学会

雑誌

遺伝学雑誌 (ISSN:0021504X)

巻号頁・発行日

vol.17, no.6, pp.310-321, 1941-12-31 (Released:2011-03-14)

著者

大西 近江 長久保 有之

出版者

日本遺伝学会

雑誌

遺伝学雑誌 (ISSN:0021504X)

巻号頁・発行日

vol.57, no.6, pp.641-650, 1982

被引用文献数

3 5

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Allelism tests among 15 independently established dwarf lines revealed that five loci are involved in dwarfism in common buckwheat. They are designated dwA, dwB, dwC, dwD and dwE. The frequencies of dwarf mutants at four loci, dwA, dwB, dwC and dwD were investigated in three Japanese populations, Iwate, Togakushi, Higashi-Iyayama, by using four representative homozygous lines as the testers. The frequencies varied slightly among the populations, but on the average they were 0.235%, 0.067%, 0.294% and 0.196% for the dwA, dwB, dwC and dwD loci, respectively. These low allele frequencies imply that the recurrent mutation is balanced by selection against the dwarf alleles. This conclusion was confirmed by supplemental data on the frequency of dwarf mutants per gamete and a field survey of dwarf homozygotes in randomly mating populations in farmer&prime;s field. Approximately 0.50% of the gametes contain a dwarf allele, whereas the incidence of dwarfism in the randomly mating populations was only 4.25 &times;10^-6. The latter estimate was based on a study of more than 3 million plants.

著者

Motoo KIMURA

出版者

The Genetics Society of Japan

雑誌

遺伝学雑誌 (ISSN:0021504X)

巻号頁・発行日

vol.66, no.4, pp.367-386, 1991 (Released:2006-06-10)

参考文献数

67

被引用文献数

98 169

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In sharp contrast to the Darwinian theory of evolution by natural selection, the neutral theory claims that the overwhelming majority of evolutionary changes at the molecular level are caused by random fixation (due to random sampling drift in finite populations) of selectively neutral (i.e., selectively equivalent) mutants under continued inputs of mutations. The theory also asserts that most of the genetic variability within species at the molecular level (such as protein and DNA polymorphism) are selectively neutral or very nearly neutral and that they are maintained in the species by the balance between mutational input and random extinction. The neutral theory is based on simple assumptions, enabling us to develop mathematical theories based on population genetics to treat molecular evolution and variation in quantitative terms. The theory can be tested against actual observations. Neo-Darwinians continue to criticize the neutral theory, but evidence for it has accumulated over the last two decades. The recent outpouring of DNA sequence data has greatly strengthened the theory. In this paper, I review some recent observations that strongly support the neutral theory. They include such topics as pseudoglobin genes of the mouse, αA-crystallin genes of the blind mole rat, genes of influenza A virus and nuclear vs. mitochondrial genes of fruit flies. I also discuss such topics as the evolution of deviant coding systems in Mycoplasma, the origin of life and the unified understanding of molecular and phenotypic evolution. I conclude that since the origin of life on Earth, neutral evolutionary changes have predominated over Darwinian evolutionary changes, at least in number.