Mar 2006, Volume 1 Issue 1
    

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  • Improvement of the Optimum Temperature of Penicillium expansum Lipase by Site-Directed Mutagenesis
    Chen Guoren, Lin Lin
    2006, 1(1): 1-4. https://doi.org/10.1007/s11515-005-0003-6
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    In order to improve the optimum temperature of lipases, the Penicillum expansum lipase (PEL) gene was mutated by site-directed mutagenesis using overlap extension PCR technique. The recombinant plasmid containing mutant E83V pPIC3.5K-lip-E83V was expressed in Pichia pastoris GS115. Comparison experiments of the mutant PEL-E83V-GS and the wild-type PEL-GS showed that the optimum temperature (45 °C) of the mutant was 5 °C higher than that of the wild type. The thermostability of the mutant was similar to that of the wild type. The enzymatic activity of the mutant was 188 U/ml at 37 °C, which was 80% that of the wild type in the same conditions. Hydrophobic interaction may be enhanced in the surface region by the hydrophilic amino acid Glu substituted with the hydrophobic amino acid Val, and may be responsible for the improvement of the optimum temperature.
  • Geographical Distribution of Phacellaria Benth. (Santalaceae) and its Hosts
    Li Dongxue, Ding Yulong
    2006, 1(1): 5-8. https://doi.org/10.1007/s11515-005-0005-4
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    Based on the geographical distribution of the species of Phacellaria and its host plants in the world, we speculated on the possible time, sites, and migration of the origin of Phacellaria. The host plants of Phacellaria mainly belong to Loranthaceae. Plants of Phacellaria and their hosts are mainly distributed in tropical and subtropical areas. The plants of Phacellaria might have originated from a tropical area in the south of China before the Tertiary. Their ancestors were parasitic on the ancestors of some plants of Loranthaceae by chance during the Tertiary. It possibly took them millions of years to form a sturdy relationship with their hosts.
  • Studies on the Fatty Liver Diseases of Sciaenops ocellatus Caused by Different Ether Extract Levels in Diets
    Jia Gang, Feng Jian, Qin Zhibiao
    2006, 1(1): 9-12. https://doi.org/10.1007/s11515-005-0002-7
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    An experiment was conducted to study fatty liver disease caused by different ether extract levels in diets of juvenile Sciaenops ocellatus. Juvenile S. ocellatus (n=1,260; initial body weight approximately 2.73 g) were divided into nine treatment groups (triplicate groups per treatment) and fed in aquatic cases by a recirculated filtered rearing system; the temperature of the aquatic cases was maintained at 23.2±2.0° for 8 weeks. Nine kinds of diets containing different protein (38, 42, 46%) and ether extract levels (4, 8, 12%) were used. Results showed that the relative growth ratio and survival ratio of the fish fed on medium lipid diets (8%) or high ether extract diets (12%) were significantly lower than those of the fish fed on low ether extract diets (4%) (p < 0.05). There was a positive correlation between the ether extract contents in hepatopancreas of fish and the ether extract contents of diets. At the end of the experimental period, the fish of the nine experimental groups suffered from different degrees of fatty liver disease and serious illness, and death occurred in a large number of fish fed on medium (8%) and high ether extract diets (12%) from the third test week; mortality was highest in the fifth test week. The ill S. ocellatus showed symptoms of loss of appetite, lack of movement, black skin, and weight loss and eventually died. The main pathological change in ill fish was fatty liver disease. Their hepatopancreas were swollen and pale, accompanied by fatty degeneration, fatty necrosis of hepatocytes, and atrophy of the pancreas. Ultrastructural changes showed the presence of many lipid droplets and granules in the mitochondria, endoplasmic reticulum, and cell plasm of hepatocytes. Study results indicated that all the nine kinds of diets with different lipid or protein levels could cause nutritional fatty liver disease in juvenile S. ocellatus. The pathological severity and serious level of fatty liver disease in the tested fish positively correlated with the contents of the ether extract, but not with those of protein, in test diets. The increase in the level of ether extract in test diets was responsible for the direct cause of illness or death in juvenile S. ocellatus.
  • Experimental Studies on the Natural Restoration and the Artificial Culture of the Moss Crusts on Fixed Dunes in the Tengger Desert, China
    Tian Guiquan, Xu Jie, Bai Xueliang, Wang Xiandao
    2006, 1(1): 13-17. https://doi.org/10.1007/s11515-005-0006-3
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    Soil microbiotic crusts cover extensive portions of the arid and semiarid regions of the world and play an important ecological role. Moss is one of the major components in the crusts. The reproduction and establishment of the mosses are crucial to the formation of moss crusts. Bryum argenteum is the dominant species of moss crusts in the Shapotou region (104?57 2E, 37?27 2N) of the Tengger Desert. In search for the characteristics of natural reproduction and establishment of the mosses, 10 quadrates (10?10 cm for each) were obtained by removing the moss crusts in different positions of fixed dunes. These 10 quadrates were observed for 3 years depending on the species  components and coverage. Meanwhile, in the third year, two quadrates (1?1 m for each) were set up in a crustabsent area and two different experiments of the asexual reproduction (broadcast planting and offshoots) were conducted, respectively. The reproductive process was observed under the microscope, and the morphological indicators of the new individuals were measured. The results were compared with the ones from indoor experiments using the same methods. All the results showed the following: (1) 70% of the quadrates (i.e., 7 of the 10 quadrates) were recovered within 3 4 years; thus, the quick recovery might be due to the dispersal and reproduction of the fragments of stems and leaves of B. argenteum; (2) as for the two quadrates in the artificial reproduction test, the new plants occupied the uncovered space of the quadrates in 1 month, and there were two main reproduction approaches, one of which was that the stems continually branched and produced young plants, and the other was that the young plants and the fragments of the stems and leaves repeatedly and extensively reproduced protonema, which finally developed into a large number of new plants; (3) the reproductive characteristics were identical, though the protonema in the field was more robust and had more branches than the ones indoors.
  • Embryological Studies on Narcissus tazetta var. chinensis
    Ge Lili, Wu Jian, Chen Linjiao, Wang Rui, Tian Huiqiao
    2006, 1(1): 18-22. https://doi.org/10.1007/s11515-005-0007-2
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    Chinese narcissus (Narcissus tazetta var. chinensis Roem) blooms but has no seeds. Embryological studies on the species were conducted to discover the causes of its sterility. Its anther wall is composed of four layers of cells, and its tapetum is of the secretory type. The cytokinesis of microspore mother cells is of the successive type, and the tetrad is tetrahedral. During meiosis of microspore mother cells, some chromosomes lagged, and several micronuclei were found in tetrads. Only 27.7% of the pollen grains contained full cytoplasm, and 1.3% of them germinated in culture medium. No pollen grain, however, could germinate on the stigma. The ovary is trilocular with axile placenta, and the ovules are bitegmic, tenuinucellate, and anatropous. Its embryo sac is of the polygonum type. Most embryo sacs degenerated, and only about 4.5% of the ovules contained a normal embryo sac with an egg cell, two synergids, three antipodal, and a central cell containing two polar nuclei. One reason for the sterility of Chinese narcissus is the abnormality of microsporogenesis and megasporogenesis, in which only a few functional pollen grains and embryo sacs are produced. The other reason is that the pollen grains cannot germinate on the stigma.
  • Genetic Differentiation and Conservation of 14 Surviving Individuals of Euryodendron excelsum Endemic to China
    Wang Ting, Su Yingjuan, Ouyang Puyue, Jiang Yu, Sun Yufei, Chen Guopei, Deng Feng, Zhang Hongda, Ye Huagu
    2006, 1(1): 23-28. https://doi.org/10.1007/s11515-005-0008-1
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    Random amplification polymorphicDNA(RAPD) markers were used to assess the genetic variations and the evolutionary relationships among all 14 individuals of a critically endangered Euryodendron excelsum (Theaceae) population distributed in Ba Jia Zhen, Yangchun, Guangdong, China. Twenty-three random primers detected 156 sites, out of which 95 (60.26%) were polymorphic loci. The number of the observed alleles was 1.6090, and the number of the effective alleles was 1.3471. Nei s gene diversity was 0.1993, and Shannon index was 0.1534. A relatively high level of genetic variation was identified in E. excelsum. An unweighted pair group method with arithmetic mean (UPGMA) tree established from Jaccard similarity coefficients suggested that 14 individuals were clustered into two subgroups and that the No. 2 plant was genetically distant from the rest of the individuals. The UPGMA clustering was also supported by a principle components analysis of RAPD phenotypic data. The management and conservation strategy of E. excelsum was proposed based on our results.
  • Isolation and Phylogenetic Analysis of Halophilic Archaeon AJ6
    Xu Xiaohong, Wu Min, Cao Yi, Wu Yuehong, Zhang Ting
    2006, 1(1): 29-34. https://doi.org/10.1007/s11515-005-0009-0
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    Halophilic archaeon AJ6 was isolated and purified from the Altun Mountain National Nature Reserve of the Xinjiang Uygur Autonomous Region. Strain AJ6 is a Gram-negative rod whose size is 0.2 0.6 by 1.6 4.2 μm, wherein a few cells are globular. The optimum salt concentration for its growth is 20% NaCl and 0.6% Mg2+, and the optimum pH is 6.0 7.0. Morphological, physiological, and biochemical characteristics of strain AJ6 were observed. The 16S rRNA encoding gene (16S rDNA) sequence of strain AJ6 was amplified by PCR, and its nucleotide sequence was determined subsequently. Clustalw  and PHYLIP  software bags were used to analyze the 16S rDNA sequence; the homology was compared, and then the phylogenetic tree was established. The results indicate that strain AJ6 is a novel species of the genus Natrinema. The GenBank accession number of the 16S rDNA sequences of strain AJ6 is AY277584.
  • Screening and Characterization of the High-Cellulase-Producing Strain Aspergillus glaucus XC9
    Xu Chang, Long Minnan, Wu Xiaobing, Xu Huijuan, Zhang Fengzhang, Xu Liangshu, Chen Zhongan
    2006, 1(1): 35-40. https://doi.org/10.1007/s11515-005-0010-7
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    Cellulose is a kind of renewable resource that is abundant in nature. It can be degraded by microorganisms such as mildew. A mildew strain with high cellulase activity was isolated from mildewy maize cob and classified as Aspergillus glaucus XC9 by morphological and 18S rRNA gene sequence analyses. We studied the effects of nitrogen source, initial pH, temperature, incubation time, medium composition, and surfactants on cellulase production. Maximal activities of carboxymethylcellulase (6,812 U/g dry koji) and filter paperase (172 U/g dry koji) were obtained in conditions as follows: initial pH, 5.5 6.0; temperature, 30?C; cultivation period, 3  4 days; inoculum ratio, 6% (vol/vol); sugarcane bagasse/wheat bran ratio, 4:6. When bagasse was used as substrate and mixed with wet koji at a 1:1 (wt/wt) ratio, the yield of reducing sugars was 36.4%. The corresponding conversion rate of cellulose to reducing sugars went as high as 81.9%. The results suggest that A. glaucus XC9 is a preferred candidate for cellulase production.
  • Biochemistry and Genetic Analysis of Bioeffects of Low Energy N+ Implantation and Y-Radiation on Arabidopsis thaliana
    Shi Xiaoming, Li Ke, Nie Yanli, Zhang Genfa
    2006, 1(1): 41-45. https://doi.org/10.1007/s11515-005-0011-6
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    We analyzed the activities of specific enzymes, esterase and peroxidase, and the electrophoresis profiling of isozymes of both the second-generation (M1) and the third-generation (M2) individuals of Arabidopsis thaliana after the parental generation was treated with low-energy N+ implantation and γ-radiation. Results indicated that the mutagenic effects of both treatments were inheritable. The obvious difference between N+ implantation and γ-radial on the relationship of doses and effects was also observed. For the correlation between effects and doses, the former presented a particular saddle-like pattern, while the latter showed a pattern of linearity. Random amplification of polymorphic DNA analysis showed that the variant DNA bands were consistent in M1 and M2 generations treated with both γ-radiation and ion implantation. However, the ratio of individual plant variation between the two treatments was remarkably different.
  • Different Responses of Sexual and Asexual Reproduction of Arundinella hirta to Flooding
    Zeng Bo, Fu Tianfei, Ulrich Schurr, Arnd J. Kuhn
    2006, 1(1): 46-49. https://doi.org/10.1007/s11515-005-0012-5
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    The sexual and asexual reproductive features of the graminoid species Arundinella hirta growing at riversides of the Jialing River were analyzed. It was found that the total seed mass, seed number per plant, and sexual reproductive allocation of A. hirta decreased with decreasing bank elevation, and plants growing at the lowest elevations of banks subjected to intense flooding did not show sexual reproduction. The total plant biomass and the number of ramifications per plant increased with flooding intensity, which implies that, contrary to sexual reproduction, asexual reproduction of A. hirta was enhanced by flooding.
  • Molecular cloning of the obese gene from Cyprinus carpio and its expression in Escherichia coli
    Dai Hanchuan, Long Liangqi, Ding Guang
    2006, 1(1): 50-55. https://doi.org/10.1007/s11515-005-0013-4
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    Aiming to analyze the characteristics of the Cyprinus carpio obese gene structure and the biological activity of its expression product, we amplified the carp obese gene using reverse transcription polymerase chain reaction from carp mesentery adipose tissue RNA. Sequence analysis revealed that it has a length of 438 nt, which encodes a 146-amino acid peptide. When nucleotide sequence and deduced amino acid sequence were compared with homologous sequences from those of humans, pigs, and rats, they displayed a fairly high degree of conservation (the homology of the nucleotide sequence was 84%, 86%, and 95%, respectively, while that of the amino acid sequence was 84%, 82%, and 96%, respectively, for humans, pigs, and rats). The cDNA fragment was inserted into the expression vector pET-28a, and the resulting plasmid was expressed in Escherichia coli BL21 (DE3) by isopropylthiogalactoside induction. Results of sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis indicated that a fusion protein was specifically expressed in E. coli BL21 (DE3). The weight of the fusion protein was about 20 kDa, and a 16-kDa protein was expressed from the carp obese gene. By gel thin-layer scanning analysis, the amount of target protein was determined to be about 20%. The purified product was found to be biologically active and to reduce the food intake and body weight of mice during tests.
  • Screening of Peptide Inhibitors of TACE from a Phage Display Random 15-Peptide Library by Recombinant TACE Ectodomain
    Huang Wei, Yang Yuzhen, Wang Zhen, Hang Ling
    2006, 1(1): 56-60. https://doi.org/10.1007/s11515-005-0014-3
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    Tumor necrosis factor (TNF)-α-converting enzyme (TACE) is the major protease responsible for processing pro-TNF-α from membrane-anchored precursors to secreted TNF-α. In the present study, a 15-peptide library was used to identify potential TACE antagonists. To obtain the recombinant TACE ectodomain and to use it as a selective molecule for the screening of peptide inhibitors of TACE, cDNA coding for the catalytic domain (T800) and full-length ectodomain (T1300) of TACE were amplified by reverse transcription polymerase chain reaction. The expression plasmid were constructed by inserting T800/T1300 into plasmid pET-28a/c respectively and were transformed into Escherichia coli BL21 (DE3). Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDSPAGE) andWestern blot analysis revealed that T800/T1300 were highly expressed in the form of an inclusion body induced by isopropylthiogalactoside. After Ni2+ NTA resin affinity chromatography, the purity of the recombinant T800/T1300 protein was more than 90%. T800 and T1300 proteins were used in the screening of T800/T1300-binding peptides from a phage display random 15-peptide library. After four rounds of biopanning, the positive phage clones were analyzed by enzyme-linked immunosorbent assay, competitive inhibition assay (ELESA), and DNA sequencing. A common amino acid sequence (TRWLVYFS RPYLVAT) was confirmed and synthesized. A synthetic peptide was shown to bind to TACE and to inhibit TNF-α release from lipopolysaccharide (LPS)-stimulated human peripheral blood mononuclear cells (PBMC) by up to 60.3%. Fluorescence-activated cell sorter (FACS) analysis revealed that the peptide mediated the accumulation of TNF-α on an LPS-stimulated PBMC surface. These results demonstrate that the TACE-binding peptide is an effective antagonist of TACE and that the deduced motif might be applied to the molecular design of anti-inflammatory drugs.
  • New Species of Genus Hedotettix Bolivar (Orthoptera: Tetrigoidea) from Yunnan Province, China
    Zheng Zhemin, Ou Xiaohong
    2006, 1(1): 61-65. https://doi.org/10.1007/s11515-005-0015-2
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    A study on three new species of the genus Hedotettix Bolivar (namely, Hedotettix grossivalva sp. nov., Hedotettix brachynota sp. nov., and Hedotettix xueshanensis sp. nov.) from Yunnan Province, China, was performed. All their specimens are deposited in the insect specimen laboratory of the Department of Resources, Southwest Forestry College (Kunming, China). The appendix presents a catalog of subcategories of Hedotettix Bolivar from China.
  • Nest-site selection of the White Eared pheasant in southwestern Sichuan Province, China
    Wang Nan, Jia Fei, Zheng Guangmei
    2006, 1(1): 66-70. https://doi.org/10.1007/s11515-005-0016-1
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    From April to July 2003 and 2004, we surveyed the nest-site selection of the White Eared pheasant (Crossoptilon crossoptilon) in the Zhujie Monastery and in the mountain facing it in Sichuan Province, China. In this paper, we studied the nest characteristics and the clutch size of the pheasant. Habitat sampling method was used to determine the variables that might affect the nest-site selection of the White Eared pheasant. Chi-square test was used to identify which habitat type was likely to be preferred by the bird. Independent-samples t test and Mann Whitney U test were used to find which variables were important for the birds  nest-site selection. A total of 13 nests were found. Oak shrub was greatly preferred as nest sites (84.62%). Nests under a rock wall (7.69%) and a fallen tree (7.69%) were also found. The average clutch size of a White Eared pheasant is 7.33?0.54 (range, 5 11; n=12). Laying period was between April 27 and May 21. In the Zhujie area, 1 nest was in the forest and 11 nests were in oak shrubs. The species preferred oak shrub as its nesting habitat (?2=8.333, df =1, P<0.05). The bird was more likely to place its nest in sites with a high coverage, i.e. 0.5, 1, and 2 m above the ground (independent-samples t test, P<0.05), and with a large shrub diameter (Mann Whitney U test, P<0.05). The species are more likely to prefer sites with plant cover, shrub cover (independentsamples t test,P<0.05), and shrub height (Mann Whitney U test, P<0.05) in a relatively small range.
  • √2 Rule for Controlling the Tree Pattern in Forest Cut
    Luo Chuanwen, Luo Chuanwen, Li Jihong, Li Jihong
    2006, 1(1): 71-75. https://doi.org/10.1007/s11515-005-0017-0
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    A forest's productivity can be optimized by the application of rules derived from monopolized circles. A monopolized circle is defined as a circle whose center is a tree and whose radius is half of the distance between the tree itself and its nearest neighbor. Three characteristics ofmonopolized circle are proved. (1) Monopolized circles do not overlay each other, the nearest relationship being tangent. (2)"Full uniform pattern" means that the grid of trees (a×b=N) covers the whole plot, so that the distance between each tree in a row is the same as the row spacing.The total monopolized circle area with a full uniform pattern is independent on the number of trees and π/4 times the plot area. (3) If a tree is removed, the area of some trees's monopolized circle will increase without decreasing the monopolized circles of the other trees. According to the above three characteristics, "uniform index" is defined as the total area of monopolized circles in a plot divided by the total area of the monopolized circles, arranged in auniform pattern in the same shaped plot. According to the definition of monopolized circle, the distribution of uniform index (L)=
    x2(2n)
    2πn
    for a random pattern and E(L)=1/π; the variance of L is De(L)=. It is evident that E(L) is independent on N and the plot area; hence, L is a relative index. L can be used to compare the uniformity among plots with different areas and the numbers of trees. In a random pattern, where L is equivalent to the tree density of the plot in which the number of trees is 1 and the area is Φ,the influence of tree number and plot area to L is eliminated. When n!?, D(L)!?0 and L!?1/Φ=0.38 ; it indicates that the greater the number of tree is in the plots,the smaller the difference between the uniform indices will be. There are three types of patterns for describing tree distribution (aggregated, random, and uniform patterns).Since the distribution of L in the random pattern is accurately derived, L can be used to test the pattern types.The research on Moarshan showed that the whole plot hasan aggregated pattern; the first, third, and sixth parts havean aggregated pattern; and the second, fourth, and fifth parts have a random pattern. None of the uniform indices is more than 0.318 (1/Π), which indicates that uniform patterns are rare in natural forests. The rules of uniform index can be applied to forest thinning. If you want to increase the value of uniform index, you must increase the total area of monopolized circles, which can be done by removing select trees. "Increasing area trees" are the removed trees and can increase the value of the uniform index. A tree is an increasing area tree if the distance between the tree and its second nearest neighbor is "2 times longer than that between the tree itself and its first nearest neighbor, which is called the "2 rule. It was very interesting to find that when six plots were randomly separated from the original plot, the proportion of increasing areatrees in each plot was always about 0.5 without exception.In random pattern, the expected proportion of increasing area trees is about 0.35-0.44, which is different from the sampling value of 0.5. The reason is very difficult to explain, and further study is needed. Two criteria can be used to identify which trees should be removed to increase the uniform index during forest thinning. Those trees should be (1) trees whose monopolized circle areas are on the small side and (2) increasing area trees, which are found via the "2 rule.
  • Concept and Classification of Coarse Woody Debris in Forest Ecosystems
    Yan Enrong, Wang Xihua, Huang Jianjun
    2006, 1(1): 76-84. https://doi.org/10.1007/s11515-005-0019-y
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    Coarse woody debris (CWD) is generally considered as dead woody materials in various stages of decomposition, including sound and rotting logs, snags, and large branches. CWD is an important functional and structural component of forested ecosystems and plays an important role in nutrient cycling, long-term carbon storage, tree regeneration, and maintenance of heterogeneous environmental and biological diversity. However, the definition and classification of CWD have been the subject of a long debate in forest ecology. CWD has not been precisely defined. Recently, with the rapid development of landscape ecology in CWD, the USDA Forest Service and the Long Term Ecological Research (LTER) have provided a standardized definition and classification for CWD, which makes data comparison in landscape scale possible. Important characteristics of their definition include: (1) a minimum diameter (or an equivalent crosssection) of CWD "e10 cm at the widest point (the woody debris with a diameter from 1 to 10 cm should be defined as fine woody debris, and the rest is litterfall); and (2) sound and rotting logs, snags, stumps, and large branches (located above the soil), and coarse root debris (larger than 1 cm in diameter). This classification has greatly facilitated CWD studies. Therefore, it has been widely applied in some countries (particularly in North America). However, this classification has long been a source of confusion for forest ecologists in China. Furthermore, different definitions and criteria are still adopted in individual studies, which makes the interpretation and generalization of their work difficult. This article reviewed recent progress in classifying CWD, with an emphasis on introducing the classification system of the USDA Forest Service and the LTER. It is expected that this review will help facilitate the development of standardized definition and classification suitable to forest ecosystems in China.
  • Segregation Analysis on Genetic System of Quantitative Traits in Plants
    Gai Junyi
    2006, 1(1): 85-92. https://doi.org/10.1007/s11515-005-0001-8
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    Based on the traditional polygene inheritance model of quantitative traits, the author suggests the major gene and polygene mixed inheritance model. The model was considered as a general one, while the pure major gene and pure polygene inheritance model was a specific case of the general model. Based on the proposed theory, the author established the segregation analysis procedure to study the genetic system of quantitative traits of plants. At present, this procedure can be used to evaluate the genetic effect of individual major genes (up to two to three major genes), the collective genetic effect of polygene, and their heritability value. This paper introduces how to establish the procedure, its main achievements, and its applications. An example is given to illustrate the steps, methods, and effectiveness of the procedure.