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41.
运用聚丙烯酰胺凝胶等电聚焦(PAGIF)和免疫吸引技术,研究了3个地区汉族人群的C6多态性。得到的基因频率如下:漳州市——C6*A:0.4634、C6*B:0.5000、C6*R:0.0366(C6*B2:0.0317);成都市——C6*A:0.4975,C6*B:0.4484,C6*R:0.0545(C6*B2:0.0395);哈尔滨市——C6*A:0.4708,C6*B:0.5219,C6*R:0.0073(C6*B2:0.0073)。蒙古人种的C6*A频率一般都低于0.5,高加索人种的C6*A频率一般都高于0.6。黑人则介于两者之间。蒙古人种与高加索人种的另一个区别在于前者的C6*B2频率在0.03到0.07之间,而后者几乎没有C6*B2。 相似文献
42.
Evidence is presented that in the R and P genomes (Secale cereale andAgropyron cristatum, respectively) of theTriticeae there exist closely related 350-family DNA sequences in the terminal heterochromatin. This observation is compared to the relationships between these two genomes derived from a comparison of theNor and5 S DNA loci as well as the available data on morphological characters, chromosome pairing, and isozyme studies. It is concluded that the R and P genomes are not closely related and that the common presence of very similar 350-family DNA sequences reflects the parallel amplification of this family of DNA sequences. 相似文献
43.
I. Hoeschele 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1988,76(2):311-319
Summary Statistical techniques for detection of major loci and for making inferences about major locus parameters such as genotypic frequencies, effects and gene action from field-collected data are presented. In field data, major genotypic effects are likely to be masked by a large number of environmental differences in addition to additive and nonadditive polygenic effects. A graphical technique and a procedure for discriminating among genetic hypotheses based on a mixed model accounting for all these factors are proposed. The methods are illustrated by using simulated data.Journal Paper No. J-12733 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project No. 1901 相似文献
44.
45.
J Piskur 《Molecular & general genetics : MGG》1988,214(3):425-432
Summary Mitochondrial DNAs (mtDNA) from four stable revertant strains generated from high frequency petite forming strains of Saccharomyces cerevisiae have been shown to contain deletions which have eliminated intergenic sequences encompassing ori1, ori2 and ori7. The deleted sequences are dispensable for expression of the respiratory phenotype and mutant strains exhibit the same relative amount of mtDNA per cell as the wild-type (wt) parental strain. These deletion mutants were also used to study the influence of particular intergenic sequences on the transmission of closely linked mitochondrial loci. When the mutant strains were crossed with the parental wt strains, there was a strong bias towards the transmission into the progeny of mitochondrial genomes lacking the intergenic deletions. The deficiency in the transmission of the mutant regions was not a simple function of deletion length and varied between different loci. In crosses between mutant strains which had non-overlapping deletions, wt mtDNA molecules were formed by recombination. The wt recombinants were present at high frequencies among the progeny of such crosses, but recombinants containing both deletions were not detected at all. The results indicate that mitochondrial genomes can be selectively transmitted to progeny and that two particular intergenic regions positively influence transmission. Within these regions other sequences in addition to ori/rep affect transmission.This paper is dedicated to colleagues J. Jana, D. Tasi, I. Bortner, and F. Zavrl 相似文献
46.
47.
Summary Stage V and VI (Dumont, J.N., 1972.J. Morphol.
136:153–180) oocytes ofXenopus laevis were treated with collagenase to remove follicular cells and were placed in K-free solution for 2 to 4 days to elevate internal [Na]. Na/K pump activity was studied by restoring the eggs to normal 3mm K Barth's solution and measuring membrane current-voltage (I–V) relationships before and after the addition of 10 m dihydroouabain (DHO) using a two-microelectrode voltage clamp. Two pulse protocols were used to measure membraneI–V relationships, both allowing membrane currents to be determined twice at each of a series of membrane potentials: (i) a down-up-down sequence of 5 mV, 1-sec stair steps and (ii) a similar sequence of 1-sec voltage pulses but with consecutive pulses separated by 4-sec recovery periods at the holding potential (–40 mV). The resulting membraneI–V relationships determined both before and during exposure to DHO showed significant hysteresis between the first and second current measurements at each voltage. DHO difference curves also usually showed hysteresis indicating that DHO caused a change in a component of current that varied with time. Since, by definition, the steady-state Na/K pumpI–V relationship must be free of hysteresis, the presence of hysteresis in DHO differenceI–V curves can be used as a criterion for excluding such data from consideration as a valid measure of the Na/K pumpI–V relationship. DHO differenceI–V relationships that did not show hysteresis were sigmoid functions of membrane potential when measured in normal (90mm) external Na solution. The Na/K pump current magnitude saturated near 0 mV at a value of 1.0–1.5 A cm–2, without evidence of negative slope conductance for potentials up to +55 mV. The Na/K pump current magnitude in Na-free external solution was approximately voltage independent. Since these forward-going Na/K pumpI–V relationships do not show a region of negative slope over the voltage range –110 to +55 mV, it is not necessary to postulate the existence of more than one voltage-dependent step in the reaction cycle of the forward-going Na/K pump. 相似文献
48.
T. Endo T. Komiya M. Mino K. Nakanishi S. Fujita Y. Yamada 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1988,76(5):641-646
Summary The genetic instability of an intertribal hybrid cell line, Duboisia hopwoodii + Nicotiana tabacum, obtained by mechanical isolation of a single hybrid cell was studied. Ten subclones of calli derived from this hybrid cell line were cultured for 3 years, and their genetic makeup clarified as to nuclear DNA content, chromosome constitution, and peroxidase isozymes. Nuclear DNA content differed in each subclone. In most subclones, mean DNA content was lower than the mean DNA content in the original hybrid cell line determined 1 year after fusion. This decrease in DNA content is partly attributable to the elimination of tobacco chromosomes that occurred in all subclones. The extent to which tobacco chromosomes were eliminated varied among the subclones — evidence that chromosome elimination occurred slowly. Peroxidase isozyme analysis indicated the loss of a tobacco-specific isozyme, thus confirming results obtained by chromosome analysis. Shoots regenerated from two hybrid subclones after 2 years were also heterogeneous in morphology and nuclear DNA content. 相似文献
49.
N. M. Cowen 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1988,75(6):857-862
Summary Seven types of progeny are described which can be used in detection of linkage between marker loci and quantitative trait loci (QTL) in a cross between two inbred lines. Three types of progeny: recombinant inbred lines (RI); doubled haploid lines (DH); and S1 lines can be used to detect linked main effects, d. DH and RI lines can be used to detect smaller effects than S1 lines. However, S1 lines can also be used to detect within-population dominance effects, h. The smallest d detectible is in the range of 1/2 to 1/12 the size of the corresponding LSD(0.05) for the quantitative trait, using 100 lines and 6 replicates. The smallest h detectible is 3–4 times this size. Four types of progeny can be used to detect differences in the dominance behavior of alleles within the population relative to an allele in another inbred line (P4: DH lines x P4; RI lines x P4; either F2 x P4 or S1 lines x P4; and progeny generated by crossing (F1 x P3) x P4. Dominance differences in the range of 1 1/4 to 1/6 the size of the corresponding LSD(0.05) are routinely detectible using 100 lines and 6 replicates. Increasing the numbers of progeny evaluated or the number of replicates allows for the detection of relatively smaller linked effects.Contribution of United AgriSeeds, Inc. 相似文献
50.
Von H. Zwölfer J. Herbst 《Journal of Zoological Systematics and Evolutionary Research》1988,26(5):320-340
Preadaptation, host shifts and parallel cladogenesis in the evolution of phytophagous insects In this contribution we investigate the possibilities to apply concepts developed for the evolution of animal parasites to insect-plant systems. We compare host parasite systems in animals with plant-herbivore systems and list similarities and differences. The terms preadaptation, predisposition, expansion and contraction of host ranges, and parallel cladogenesis are discussed. We enumerate general preadaptations for the evolution of herbivory in insects and preadaptations for shifts between herbivory and entomophagy. Examples are given for expansions of host ranges based on phytochemical or structural characters of host plants. Cases of parallel cladogenesis in herbivoreparasitoid systems and plant-herbivore systems are compiled from the literature. An analysis of the insect fauna of the “thistles” (Cynaroideae) in the Palearctic and Nearctic demonstrates the importance of the evolutionary history of the plant taxa and of the existence of preadapted pools of herbivores for the evolution of guilds of specialized herbivores. The members of the Curculionid taxon Cleoninae provide examples for multiple colonizations and radiations of herbivores on the Cynaroideae. The taxonomic and biological relationships of the weevil genera Rhinocyllus, Bangasternus and Larinus which exploit the flower heads of Cynaroideae, can be interpreted as result of a basic parallel cladogenesis between herbivore and host. A gelelectrophoretic analysis of Larinus spp. supports this hypothesis. 相似文献