In Senegal in particular, ovarian cancer, which is one of the most common gynecological cancers, accounts for 2.8% of deaths. The most important risk factor is genetic, with 10% of cases occurring in a context of gene...In Senegal in particular, ovarian cancer, which is one of the most common gynecological cancers, accounts for 2.8% of deaths. The most important risk factor is genetic, with 10% of cases occurring in a context of genetic predisposition. The sequencing of the human genome, which has led to the discovery of millions of sequence variations, makes it possible to study variations within sequences. These variations are limited to Single Nucleotide Polymorphisms (SNPs) and this common form of polymorphism occurs approximately every 1000 bases in the human genome and 1.8 million SNPs are currently listed according to [1]. The aim of this study is to gain a better understanding of the impact of mutations in the D-loop region of mtDNA on ovarian cancer in Senegalese women. This study involved searching for mutations in our study population after DNA extraction and sequencing. Mutations were found after a comparison of our sequences with the Cambridge reference sequence (NC_012920). The mutations found in the DNA studied extend from position 7 to position 16568 and most of these mutations are located in the hypervariate zones (HV1 and HV2). Heteroplasmy with three mutant alleles was also found in certain variants. Common mutations were found in both healthy and cancerous tissues, with almost identical frequencies in both types of tissue. This enabled us to understand the spread of tumor cells throughout the ovary.展开更多
Complete mitochondrial D-loop sequences of 140 samples obtained from 15 Chinese local cattle breeds were analyzed.The result showed 67 different haplotypes with 113 polymorphic sites.The haplotype diversity and nucleo...Complete mitochondrial D-loop sequences of 140 samples obtained from 15 Chinese local cattle breeds were analyzed.The result showed 67 different haplotypes with 113 polymorphic sites.The haplotype diversity and nucleotide diversity were 0.608-1.000 and 0.002-0.028,respectively,indicating abundant genetic diversity in Chinese cattle.The constructed Neighbor-Joining(NJ) tree revealed that there were two maternal origins of Bos taurus and Bos indicus in Chinese cattle.Among them,the Bos taurus lineage had rich mtDNA genetic diversity,while Bos indicus lineage had poor mtDNA genetic diversity,respectively.It can be concluded that the cattle in Northern China originated from the Bos taurus lineage,while the cattle in Central China and Southern China originated from Bos taurus and Bos indicus lineages.In our study,two mtDNA haplotypes belonging to African cattle were detected,thus providing molecular evidence for an African lineage in Chinese cattle.展开更多
文摘[目的]研究庆阳驴养殖群体的遗传多样性与母系起源,了解其遗传信息,为保护庆阳驴种质资源、选育和遗传改良工作提供理论依据。[方法]随机选取133头庆阳驴,对其线粒体DNA(mitochondrial DNA,mtDNA)D-loop区序列进行PCR扩增、测序及比对,并探讨庆阳驴的遗传多样性与母系起源。[结果]在获得的520 bp D-loop碱基序列中,AT含量(57.3%)高于GC含量(42.8%),表现出碱基的偏倚性;检测到38个变异位点,包含8个碱基对的转换;其核苷酸多样性(Pi)、单倍型多样性(Hd)、平均核苷酸差异(K)分别为0.01591、0.895和8.274,与欧洲家驴和中国家驴研究的平均值相比较低,说明该驴品种核苷酸变异较为贫乏。庆阳驴mtDNA D-loop区存在35个单倍型,单倍型之间的遗传距离为0.002~0.042。系统进化结果显示,庆阳驴存在2个线粒体支系,表明其具有2个母系起源,且遗传距离表明,庆阳驴与克罗地亚家驴之间的遗传距离较近。[结论]本研究从分子水平初步揭示庆阳驴核苷酸变异比较贫乏,杂交程度高,mtDNA遗传多态性正逐步丧失,应加强庆阳驴品种的遗传资源保护工作。
文摘In Senegal in particular, ovarian cancer, which is one of the most common gynecological cancers, accounts for 2.8% of deaths. The most important risk factor is genetic, with 10% of cases occurring in a context of genetic predisposition. The sequencing of the human genome, which has led to the discovery of millions of sequence variations, makes it possible to study variations within sequences. These variations are limited to Single Nucleotide Polymorphisms (SNPs) and this common form of polymorphism occurs approximately every 1000 bases in the human genome and 1.8 million SNPs are currently listed according to [1]. The aim of this study is to gain a better understanding of the impact of mutations in the D-loop region of mtDNA on ovarian cancer in Senegalese women. This study involved searching for mutations in our study population after DNA extraction and sequencing. Mutations were found after a comparison of our sequences with the Cambridge reference sequence (NC_012920). The mutations found in the DNA studied extend from position 7 to position 16568 and most of these mutations are located in the hypervariate zones (HV1 and HV2). Heteroplasmy with three mutant alleles was also found in certain variants. Common mutations were found in both healthy and cancerous tissues, with almost identical frequencies in both types of tissue. This enabled us to understand the spread of tumor cells throughout the ovary.
文摘Complete mitochondrial D-loop sequences of 140 samples obtained from 15 Chinese local cattle breeds were analyzed.The result showed 67 different haplotypes with 113 polymorphic sites.The haplotype diversity and nucleotide diversity were 0.608-1.000 and 0.002-0.028,respectively,indicating abundant genetic diversity in Chinese cattle.The constructed Neighbor-Joining(NJ) tree revealed that there were two maternal origins of Bos taurus and Bos indicus in Chinese cattle.Among them,the Bos taurus lineage had rich mtDNA genetic diversity,while Bos indicus lineage had poor mtDNA genetic diversity,respectively.It can be concluded that the cattle in Northern China originated from the Bos taurus lineage,while the cattle in Central China and Southern China originated from Bos taurus and Bos indicus lineages.In our study,two mtDNA haplotypes belonging to African cattle were detected,thus providing molecular evidence for an African lineage in Chinese cattle.
