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Copyright of South China Fisheries Science is the property of South China Fisheries Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Bulletin of Botanical Research is the property of Bulletin of Botanical Research Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Oil Crop Sciences is the property of Oil Crops Research Institute of Chinese Academy of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Genetic drift is one of the difficulties in teaching genetics due to its randomness and probability which could easily cause conceptual misunderstanding. The “sampling error" in its definition is often misunderstood because of the research method of “sampling", which disturbs the results and causes the random changes in allele frequency. I analyzed and compared the definitions of genetic drift in domestic and international genetic textbooks, and found that the definitions containing “sampling error" are widely adopted but are interpreted correctly in only a few textbooks. Here, the history of research on genetic drift, i.e., the contributions of Wright, Fisher and Kimura, is introduced. Moreover, I particularly describe two representative articles recently published about genetic drift teaching of undergraduates, which point out that misconceptions are inevitable for undergraduates during the studying process and also provide a preliminary solution. Combined with my own teaching practice, I suggest that the definition of genetic drift containing “sampling error" can be adopted with further interpretation, i.e., “sampling error" is random sampling among gametes when generating the next generation of alleles which is equivalent to a random sampling of all gametes participating in mating in gamete pool and has no relationship with artificial sampling in general genetics studies. This article may provide some help in genetics teaching.

Objective: To understand the genotype characteristics and its evolution of patients with poor response to initial combined treatment of Lamivudine and Adefovir dipivoxil for chronic hepatitis B., Methods: We detected the HBV genotypes of three patients-S1, S2, S3, who with poor response to initial treatment of Lamivudine and Adefovir dipivoxil for chronic hepatitis B over 12 months by the application of cloning and sequencing method at the time point of baseline,4 weeks after treatment, 12 weeks, 24 weeks, 48 weeks, 60 weeks. 25 clones were randomly selected to identify and sequence at each time point., Results: The total number of clones from 3 patients with poor response to initial combined treatment of Lamivudine and Adefovir dipivoxil for chronic hepatitis B at each time point was 398. About patient S1 at baseline, genotype C accounting for 8.3%, genotype B, for 91.7%, so genotype B was in dominant (22/24). But genotype C has gradually developed to 100% after treatment for 60 weeks. About patient S2 and S3, genotype B was the only type at baseline. However type B has gradually "drift" to type C during treatment. When treatment for 60 weeks, type C has taken the absolute advantage 75% for S2, and 100% for S3., Conclusions: The cloning and sequencing can represent the overall genotype level better. HBV genotype has performed the evolution trend that genotype has drifted from B to C during long-term drug pressure, which is the main reason for poor response to initial combined treatment of Lamivudine and Adefovir dipivoxil for chronic hepatitis B.

Objective: To determine the epidemiological characteristics of seasonal influenza in Shenzhen from 2005 to 2007 and the molecular variation of HA1 domain of influenza H3N2 viruses., Methods: The consultation rate for influenza-like illness (ILI) were calculated weekly for indicating the influenza activities (the Shenzhen Influenza Surveillance System mainly consisted of 16 institutions with 9 hospitals, 6 districts and one municipal centers of disease control and prevention). Pharyngeal swabs from the cases of ILI, which were collected during 2005 to 2007 from the city-wide and quality-controlled surveillance network, were used to propagate the viruses. The HA1 region of the influenza A/H3N2 viruses were detected by RT-PCR and sequenced subsequently. The analyses of pairwise amino acid variations, genetic clustering and phylogenetics was performed., Results: The activity levels of influenza showed certain changes during each year from 2005 to 2007, and there were summer peaks from May to July in 2006 and 2007. The positive rates of influenza virus were 4.78% (114/2385), 5.77% (212/3674) and 12.12% (343/2831) from 2005 to 2007 respectively. The weekly isolating rates changed accordingly with the trend of the percentages of ILI. The proportions of influenza H3N2 virus were 25.46% (28/114) and 2.83% (6/212) in 2005 and in 2006 respectively, but the proportion increased to 62.68% (215/343), which indicated that H3N2 virus became the predominant strain in 2007. Phylogenetic clustering analysis of influenza H3N2 virus revealed that there were 5 clades. The viruses which were isolated in 2005 contained in the clade I and II, the viruses in 2006 were comprised in clade III, and clade IV and V included the viruses isolated in 2007. Although the stem of cladogram developed with one accord of the time isolated viruses, the viruses which were similar to vaccine strains had circulated in Shenzhen before a given strain was determined as vaccine strain by WHO. It was also noticed that more amino acid changes at antigenic sites, especially at sites A and B in the H3N2 viruses, were found in 2007 than that in 2005 and in 2006. But the sequences at the receptor-binding sites and disulphide bond sites were conserved and no new circulating strain for genetic reassortment had been found in the period., Conclusion: Shenzhen might be one of areas where the ongoing genetic drift of influenza H3N2 viruses appeared earlier in China. The changes of influenza H3N2 virus showed the active status in the population. The results suggested that monitoring seasonal influenza viruses by sequence analysis could provide important and timely information on the appearance of strains with epidemiologic significance.

Objective: To study the relationship between influenza epidemic and genetic characteristic on HA and NA regions of influenza virus subtype A3 isolates of Zhejiang province in the recent years., Methods: RNA of 25 influenza virus subtype A3 isolates, circulated in Zhejiang province during 1998 to 2005, was extracted. HA1 and NA regions were amplified and sequenced. All the sequence data were analyzed using BioEdit., Results: HA1 and NA regions of all the isolates belonged to 987nt and 1362nt, encoding protein of 329 and 454 amino acids respectively. Isolates shared amino acid homology of 90.9%-99.3% and 95.2%-99.5% on HA1 and NA regions, while divergence on HA1 was greater than that on NA region. During a period of 8 years, 30 amino acids on HA1 region were substituted and 14 of which refer to 4 antigenic determinant sites. Meanwhile,21 amino acids on NA region were substituted and 5 of which referred to 3 antigenic determinant sites. Significant divergences, both in HA1 and NA, were observed among isolates in 1998 and 2002, showing that they belonged to absolutely different branches. Additionally, influenza virus subtype A3 isolates identified in recent years, with 11 N-linked glyeosylation sites in HA1 region, had 5 sites more than early A/Aichi/2/68 strain. Since 1998,3 sites had been inserted in epidemic strains, indicating the accelerated trend of glyeosylation sites were increasing., Conclusion: There is a correlation between antigenic drift of influenza virus subtype A3 and the two epidemics in Zhejiang province in 1998 and 2002.

Objective: To analyze the drift of the complementarity-determining region 3 (CDR3) of T cell receptor beta (TCRbeta) chain variable region in T cells of healthy volunteers cultured with interleukin-2 (IL-2)., Methods: T cells were isolated from the peripheral blood and cultured in vitro in the presence of IL-2. The non-specific killing effect of the cells was analyzed by LDH releasing assay, and the distribution of TCRbeta chain CDR3 in healthy volunteers by immunoscope spectratyping method to evaluate the clonality of the T cells., Results: The results showed Gaussian distribution of TCR Vbeta gene CDR3 in healthy volunteers. The T cell cultured with IL-2, however, displayed some anomalous and oligoclonal expansion in different TCR Vbeta families without killing effect against nasophargngal carcinoma cell line CNE2., Conclusion: IL-2 may affect TCRbeta chain CDR3 distribution in T cells cultured in vitro.

Gene flow was analyzed among four sheep breeds of Mongolian Group in China using structural gene loci and microsatellite markers.Results showed that genetic differentiation was 0.0164-0.0455 by using structural loci, and was 0.0107-0.0239 by using microsatellite loci.This illustrated that most variations existed within breeds and genetic differentiation level was very low among sheep breeds of Mongolian Group in China.There was substantial Gene flow among the breeds as estimated by the structural loci (Nm=7.971) or the microsatellite method(Nm=15.732).There was no direct relationship between genetic differences from breeds and geographical distances.It is concluded that genetic differentiation of sheep breeds of Mongolian Group in China is mainly the result of natural selection (different living conditions).

The 1 042 bp control region of mitochondrial DNA from 84 geese of 15 domestic goose breeds was sequenced and genetic differentiation was analysed. Results showed that the interpopulation nucleotide divergence was highest (3.805% -4.067%) between Yili and the other 14 breeds. The average nucleotide diversity variation within different domestic breeds was 0 - 0.116%. Excluding the Yili, the interpopulation nucleotide divergence between Huoyan and the remaining breeds, was 0.211% - 0.272%, which was significantly higher than that between any other two breeds (0 -0.094%). During the formation of domestic breeds in China,there is an association between the genetic differentiation of domestic geese and their geographic distribution. The divergence time of Huoyan breed was relatively earlier and genetic drift may have been the main factor to affect the genetic differentiation of the Huoyan breed (Nm = 0.02 -0.54). On the other hand, gene flow is the main reason for the lack of a clear differentiation among the remaining 13 Chinese domestic geese breeds (Nm = 12.0 - 65.33).

Objective: To understand the molecular biological characteristics in order to analyse the genetic background of Yersinia pestis in China., Methods: Primary datum on ribotyping, pulsed field gene electrophoresis (PFGE), random amplified polymorphic DNA (RAPD) and insertion sequence (IS) of Yersinia pestis were used and under cluster analysis. Genetic interval and various methods of recognized molecular feature between different strains were evaluated., Results: Ribotypes the PFGE types seemed to be corresponding. Stains from Microtus fuscus and area in Tibet Zhongba belonged to 7 copy rRNA gene and the genetic interval were the far more with 6 copy rRNA gene stains, and not definite with RAPD, but with many exceptions. The genetic interval between strains were showed by resemble value., Conclusion: Yersinia pestis in China had its own manifold, particular molecular biological characteristics due to natural barriers, geographical complex, circumstances in Tianshan Mountains and Gandise Mountains areas. Yersinia pestis were limited to separateness, evoluted only in certain areas to form a great many gene types.

The difference of population genetic structure is one of the important embodiments of genetic diversity. There is a long history of the study of population genetic structure, and the study of gene flow of population genetic structure is aroused more and more importance. It has an important effect on population genetics, evolution biology, conservation biology and ecology. Although the level of gene flow is estimated by traditional population genetics, there is a large restriction in its precision. With the development of biological technology, the methods of the research on gene flow reach the molecular level. Methods of protein electrophoresis and molecular markers (RAPD, RFLP, VNTR, ISSR and mitochondrial DNA) are used to research gene flow among populations. This paper introduces not only some models of population genetic structure: Continent-Island Model, Island Model, Stepping-Stone Model, Isolation-By-Distance Model and Hierarchical Model; but also the study methods, function and role of gene flow is based on models of population genetic structure, research achievements in recent years and the restriction of the methods.

Eight field populations of Culex pipiens complex collected from five provinces (Guangdong, Henan, Shandong, Beijing and Yunnan) in 2001 were used to study genetic diversity by starch gel electrophoresis. Data from seven loci (ME,MDH-1,MDH-2,MDH-3,GPD,EST-2,EST-3) of four isozymes were analyzed by software Biosys2.0 and FSTAT(Version 2.9.3). The results were as follows: (1) The values of He (from 0.098 to 0.41) indicated genetic variabilities of different degree in populations.(2)The low level of gene flow (Nm=0.64) could not prevent genetic drift to cause the gene differentiation between populations. The genetic diversity between populations attributed to the genetic diversity of total populations is small (Gst =0.303), and the great part is accumulated within populations (Hs/Dst=2). (3) The genetic structure of Culex pipiens complex population was the isolation-by-distance model. (4) The genetic identity (or genetic distance) revealed the scale of genetic differentiation between populations which related to the collection sites.

Objective: The strains of Yersinia pestis isolated in different period and different natural foci in China were analyzed., Methods: Traditional and molecular biological methods were used. Rhamnose fermentation, rRNA gene copy number, nitrite reduction, and the glycerol fermentation were important characters for typing, and pulse field gel electrophoresis (PFGE) and random amplified polymorphic DNA (RAPD) profile could reflect the genetic distance between the strains., Results: The strains could be divided into 15 genetic types by those 6 characters with each of them covered an isolated geographical territories., Conclusion: The characters of strains were described; the genetic relationship of different types, their evolution, and the forming and shift of plague natural foci were analyzed.