乙型肝炎病毒C2、C1、B2基因型中SSR的比較分析
發(fā)布時間：2018-07-28 19:51
【摘要】：簡單重復(fù)序列(Simple sequence repeat，SSR)普遍存在于真核生物和原核生物的基因組序列中，以前SSR被認為是基因序列中的“junk DNA”，不具有生物學(xué)功能，然而，隨著研究的深入發(fā)現(xiàn)，SSR的突變率很高，且具有非常重要的生物功能，目前已發(fā)現(xiàn)的弗里德賴希共濟失調(diào)等20多種疾病均是由SSR在DNA序列中擴增造成的。乙型肝炎病毒(Hepatitis B virus，HBV)是目前已知的感染人類最小的雙鏈DNA病毒，它能夠引發(fā)急慢性肝炎，同時也會顯著地提高肝硬化、細胞性肝癌等重癥肝病的發(fā)生率。HBV具有非常高的突變率，根據(jù)HBV-DNA的異質(zhì)性，將HBV分為八種基因型(A-H)和多種基因亞型，研究表明，不同的基因型/基因亞型在地理分布、致病性、DNA序列突變、對藥物治療反應(yīng)等方面均存在差異性，，目前發(fā)現(xiàn)C2基因亞型的致癌性最強，C1基因亞型次之，B2基因亞型再次之。HBV的基因型/基因亞型為研究SSR在基因序列中的變異、進化和功能提供了很好的條件。 本論文以C2、C1、B2基因序列為材料，分析SSR在C2、C1、B2基因序列中分布的特點。結(jié)果顯示，四型SSR、五型SSR、六型SSR并沒有在分析的序列中出現(xiàn)，然而，一型SSR、二型SSR、三型SSR在每條分析的序列中均有出現(xiàn)，但其重復(fù)次數(shù)比較小和序列長度比較短，以上結(jié)果可能與HBV-DNA序列非常短和其突變率非常高有關(guān)；一型SSR (A)n和(T)n在序列中的含量遠比(G)n和(C)n在序列中的含量高；二型SSR (TG)n和(AC)n在B2基因序列中的含量遠大于其在C2、C1中的含量，(CT)n是此三種基因序列中最普遍的二型SSR，(AG)n和(TA)n在C2、C1、B2基因序列的含量比較相似；總體上分析發(fā)現(xiàn)，與B2基因亞型相比，二型SSR在C2和C1中的分布更相似；(AGA)n和(CCT)n在基因序列中的含量最豐富，且其在各序列間的波動最小，除(AGA)n和(CCT)n外的其它的三型SSR在序列中的含量非常少且波動性較大。總體上，一型SSR在序列中的分布按照C2、C1、B2的順序減少；二型SSR和總的SSR在序列中的分布是按照C2、C1、B2的順序增加的；然而，三型SSR在基因組序列中的分布與C2、C1、B2的順序之間沒有明顯的相關(guān)性。
[Abstract]:Simple sequence repeat (SSR) is commonly found in the genome sequences of eukaryotes and prokaryotes. Previously, SSR was considered to be "junk DNA" in the sequence of genes and did not have biological functions. However, with the in-depth discovery of the research, the mutation rate of SSR is very high and has very important biological functions. At present, it has been found to have been found. More than 20 diseases, such as Fredrich ataxia, are caused by the amplification of SSR in the DNA sequence. Hepatitis B virus (HBV) is currently known to be the smallest double stranded DNA virus, which can cause acute and chronic hepatitis and also significantly increase the incidence of liver cirrhosis, hepatocellular carcinoma, and severe liver disease,.HB V has a very high mutation rate. According to the heterogeneity of HBV-DNA, HBV is divided into eight genotypes (A-H) and a variety of gene subtypes. The study shows that different genotypes / genotypes have differences in geographical distribution, pathogenicity, DNA sequence mutation, and drug treatment response, and the C2 gene subtype has the strongest carcinogenicity, and the C1 gene is found. The Subgenotype of genotype B2 /.HBV genotype / genotype is a good condition to study the variation, evolution and function of SSR in the gene sequence.
In this paper, C2, C1, B2 gene sequences were used as materials to analyze the characteristics of SSR distribution in the C2, C1, B2 gene sequences. The results showed that type four SSR, type five SSR, and type six SSR did not appear in the sequence of analysis. However, a type SSR, type two SSR, and three types appeared in each analysis sequence, but the number of repetitions was smaller and the sequence length was shorter. The above results may be related to the very short sequence of HBV-DNA and the very high mutation rate; the content of SSR (A) n and (T) n in the sequence is far higher than that of (G) n and (C) n in the sequence; the content of the two type SSR (TG) and N is far greater than its content in the sequence, which is the most common two type of the sequence of these three genes. SR, (AG) n and (TA) n in the C2, C1, B2 gene sequences are similar; overall analysis found that the distribution of type two SSR in C2 and C1 is more similar than that of the B2 subtype; In general, the distribution of type 1 SSR in the sequence is reduced in order of C2, C1, B2, and the distribution of type two SSR and total SSR in sequence is increased in the order of C2, C1, B2; however, there is no significant correlation between the distribution of the type three SSR in the sequence of the genome and the order of C1, and the sequence.
【學(xué)位授予單位】：湖南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2012
【分類號】：R373
本文編號：2151403
[Abstract]:Simple sequence repeat (SSR) is commonly found in the genome sequences of eukaryotes and prokaryotes. Previously, SSR was considered to be "junk DNA" in the sequence of genes and did not have biological functions. However, with the in-depth discovery of the research, the mutation rate of SSR is very high and has very important biological functions. At present, it has been found to have been found. More than 20 diseases, such as Fredrich ataxia, are caused by the amplification of SSR in the DNA sequence. Hepatitis B virus (HBV) is currently known to be the smallest double stranded DNA virus, which can cause acute and chronic hepatitis and also significantly increase the incidence of liver cirrhosis, hepatocellular carcinoma, and severe liver disease,.HB V has a very high mutation rate. According to the heterogeneity of HBV-DNA, HBV is divided into eight genotypes (A-H) and a variety of gene subtypes. The study shows that different genotypes / genotypes have differences in geographical distribution, pathogenicity, DNA sequence mutation, and drug treatment response, and the C2 gene subtype has the strongest carcinogenicity, and the C1 gene is found. The Subgenotype of genotype B2 /.HBV genotype / genotype is a good condition to study the variation, evolution and function of SSR in the gene sequence.
In this paper, C2, C1, B2 gene sequences were used as materials to analyze the characteristics of SSR distribution in the C2, C1, B2 gene sequences. The results showed that type four SSR, type five SSR, and type six SSR did not appear in the sequence of analysis. However, a type SSR, type two SSR, and three types appeared in each analysis sequence, but the number of repetitions was smaller and the sequence length was shorter. The above results may be related to the very short sequence of HBV-DNA and the very high mutation rate; the content of SSR (A) n and (T) n in the sequence is far higher than that of (G) n and (C) n in the sequence; the content of the two type SSR (TG) and N is far greater than its content in the sequence, which is the most common two type of the sequence of these three genes. SR, (AG) n and (TA) n in the C2, C1, B2 gene sequences are similar; overall analysis found that the distribution of type two SSR in C2 and C1 is more similar than that of the B2 subtype; In general, the distribution of type 1 SSR in the sequence is reduced in order of C2, C1, B2, and the distribution of type two SSR and total SSR in sequence is increased in the order of C2, C1, B2; however, there is no significant correlation between the distribution of the type three SSR in the sequence of the genome and the order of C1, and the sequence.
【學(xué)位授予單位】：湖南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2012
【分類號】：R373
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相關(guān)期刊論文 前3條
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2 張濤;路宏朝;李新生;;微衛(wèi)星進化屬性及其功能的研究進展[J];中國農(nóng)學(xué)通報;2010年01期
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本文編號：2151403
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