为了进一步探讨大麝鼩(Crocidura lasiura)的亚种分化问题,在中国东北地区采集大麝鼩标本13号,结合已报道的大麝鼩形态学数据和Cyt b基因序列一并进行分析。形态学结果显示:在绝大多数个体中,分布于中国东北—俄罗斯远东的大麝鼩体型大...为了进一步探讨大麝鼩(Crocidura lasiura)的亚种分化问题,在中国东北地区采集大麝鼩标本13号,结合已报道的大麝鼩形态学数据和Cyt b基因序列一并进行分析。形态学结果显示:在绝大多数个体中,分布于中国东北—俄罗斯远东的大麝鼩体型大于分布于韩国的个体(体长:> 82 mm vs.<82 mm,尾长:> 39 mm vs.<39 mm,颅基长:> 20 mm vs.<20 mm);中国东北—俄罗斯远东种群体背毛色更黑,韩国种群体背毛色更灰;中国东部种群尾较长,绝大多数超过体长之半;而分布于中国东北—俄罗斯远东、韩国的大麝鼩种群尾长绝大多数不及体长之半。基于Cyt b基因的遗传距离、系统发育关系和中介网络分析,都显示大麝鼩样本可分为3个地理谱系:中国东北—俄罗斯远东谱系、韩国谱系、中国东部谱系。研究结果支持大麝鼩分为3个亚种:东北亚种(C. l. lasiura)分布于中国东北和俄罗斯远东,韩国亚种(C. l. thomasi)分布于韩国,华东亚种(C. l. campus-lincolnensis)分布于中国东部。展开更多
Sequence variation of partial cytochrome b genes between two Coilia species, C. ectenes and C. mystus, was in- vestigated. Of the 402 nucleotides, twenty-seven (6.72%) are polymorphic and all are synonymous substituti...Sequence variation of partial cytochrome b genes between two Coilia species, C. ectenes and C. mystus, was in- vestigated. Of the 402 nucleotides, twenty-seven (6.72%) are polymorphic and all are synonymous substitutions. At the third positions of genetic condon of cytochrome b gene, the two species show an extreme anti-G bias (<4%) and a pronounced bias towards A and C (>68%). There is no amino acid sequence divergence between the partial cytochrome b genes of the two species, indicating a close genetic relationship between them. The k-2p genetic distance of partial cytochrome b segment of the two species is 0.072, suggesting that the species were separated 3.6 Ma ago, in the middle Pliocene. Our result reveals that the cytochrome b gene is an appropriate marker for studies of population genetic structures and phylogeographic pat- terns of the two species.展开更多
Mitochondrial cytochrome b (Cytb), one of the few proteins encoded by the mitochondrial DNA, plays an important role in transferring electrons. As a mitochondrial gene, it has been widely used for phylogenetic analysi...Mitochondrial cytochrome b (Cytb), one of the few proteins encoded by the mitochondrial DNA, plays an important role in transferring electrons. As a mitochondrial gene, it has been widely used for phylogenetic analysis. Previously, a 949-bp fragment of the coding gene and mRNA editing were characterized from Prorocentrum donghaiense, which might prove useful for resolving P. donghaiense from closely related species. However, the full-length coding region has not been characterized. In this study, we used rapid amplification of cDNA ends (RACE) to obtain full-length, 1 124 bp cDNA. Cytb transcript contained a standard initiation codon ATG, but did not have a recognizable stop codon. Homology comparison showed that the P. donghaiense Cytb had a high sequence identity to Cytb sequences from other dinoflagellate species. Phylogenetic analysis placed Cytb from P. donghaiense in the clade of dinoflagellates and it clustered together strongly with that from P. minimum. Based on the full-length sequence, we inferred 32 editing events at different positions, accounting for 2.93% of the Cytb gene. 34.4% (11) of the changes were A to G, 25% (8) were T to C, and 25% (8) were C to U, with smaller proportions of G to C and G to A edits (9.4% (3) and 6.2% (2), respectively). The expression level of the Cytb transcript was quantified by real-time PCR with a TaqMan probe at different times during the whole growth phase. The average Cytb transcript was present at 39.27±7.46 copies of cDNA per cell during the whole growth cycle, and the expression of Cytb was relatively stable over the different phases. These results deepen our understanding of the structure and characteristics of Cytb in P. donghaiense, and confirmed that Cytb in P. donghaiense is a candidate reference gene for studying the expression of other genes.展开更多
[ Objective] To preliminarily explore the intraspecific relationship of sheep based on cytochrome b ( Cyt b) gene of mitochondrial DNA (mtDNA). [Method] The Cyt b gene sequences in 112 sheep individuals of two loc...[ Objective] To preliminarily explore the intraspecific relationship of sheep based on cytochrome b ( Cyt b) gene of mitochondrial DNA (mtDNA). [Method] The Cyt b gene sequences in 112 sheep individuals of two local sheep breeds were amplified by PCR. Then the amplified products were digested with EcoR I and analyzed by restriction fragment length polymorphism (RFLP). [ Result] As many as 56 samples from Tan sheep and 56 samples from Wadi sheep were detected. The results showed that the amplified Cyt b gene in 51 individuals of Tan sheep had one EcoR I restriction site and no EcoR I restriction site in other five individuals, thus the Cyt b gene in Tan sheep showed two restriction morphs; the Cyt b gene in all 56 individuals of Wadi sheep had one EcoR I restriction site and showed one restriction morph. [ Conclusion] The polymorphism of mitochondrial Cyt b gene in Tan sheep and Wadi sheep is poor, and the Cyt b gene in sheep breeds is very conservative. Therefore, using Cyt b gene as gene marker to study the intraspecific relationship of sheep has some limitations.展开更多
Cyt b gene of North Sulawesi Tarsius sp., T. tumpara, T. sangirensis and T. tarsier (T. spectrum) had been partially sequenced. The homologous sequence of three groups had been compared to describe the phylogenetic po...Cyt b gene of North Sulawesi Tarsius sp., T. tumpara, T. sangirensis and T. tarsier (T. spectrum) had been partially sequenced. The homologous sequence of three groups had been compared to describe the phylogenetic position among them, as well as several other species accessed from the Genbank. Total DNA extracted from the muscular tissue had been obtained through tail cut sampling using the innuPREP DNA micro kit, and amplified using a pair of universal primer, L14841 and H15149. The size of the cyt b gene sequence amplified was 307 bp long. Sequence aligned using CLUSTAL-X program and diversity analysis were done using version 5.2.2. MEGA5 program. Genetic distance had been calculated by Tamura 3 parameter method and phylogenetic tree had been built using Neighbor-Joining and Maximum Likelihood methods. Genetic distance based on cyt b gene nucleotide was found from 0 to 0.240 with an average of 0.080. The phylogenetic tree constructed by Neighbor Joining and Maximum Likelihood methods indicated that T. tarsier, T. sangirensis and T. tumpara were closely related with Tarsius tarsier-complex, and distantly related with Cephalopachus bancanus and Carlito syrichta. The genetic distance and the phylogenetic tree had been constructed on the base of partial cyt b gene sequence of T. tarsier, T. sangirensis, T. tumpara and 5 other tarsier species and their accession. Those results are consistent with taxonomy based on morphology and vocal acoustic form.展开更多
文摘为了进一步探讨大麝鼩(Crocidura lasiura)的亚种分化问题,在中国东北地区采集大麝鼩标本13号,结合已报道的大麝鼩形态学数据和Cyt b基因序列一并进行分析。形态学结果显示:在绝大多数个体中,分布于中国东北—俄罗斯远东的大麝鼩体型大于分布于韩国的个体(体长:> 82 mm vs.<82 mm,尾长:> 39 mm vs.<39 mm,颅基长:> 20 mm vs.<20 mm);中国东北—俄罗斯远东种群体背毛色更黑,韩国种群体背毛色更灰;中国东部种群尾较长,绝大多数超过体长之半;而分布于中国东北—俄罗斯远东、韩国的大麝鼩种群尾长绝大多数不及体长之半。基于Cyt b基因的遗传距离、系统发育关系和中介网络分析,都显示大麝鼩样本可分为3个地理谱系:中国东北—俄罗斯远东谱系、韩国谱系、中国东部谱系。研究结果支持大麝鼩分为3个亚种:东北亚种(C. l. lasiura)分布于中国东北和俄罗斯远东,韩国亚种(C. l. thomasi)分布于韩国,华东亚种(C. l. campus-lincolnensis)分布于中国东部。
基金the Major State Basic Research Development Program(G19990437).
文摘Sequence variation of partial cytochrome b genes between two Coilia species, C. ectenes and C. mystus, was in- vestigated. Of the 402 nucleotides, twenty-seven (6.72%) are polymorphic and all are synonymous substitutions. At the third positions of genetic condon of cytochrome b gene, the two species show an extreme anti-G bias (<4%) and a pronounced bias towards A and C (>68%). There is no amino acid sequence divergence between the partial cytochrome b genes of the two species, indicating a close genetic relationship between them. The k-2p genetic distance of partial cytochrome b segment of the two species is 0.072, suggesting that the species were separated 3.6 Ma ago, in the middle Pliocene. Our result reveals that the cytochrome b gene is an appropriate marker for studies of population genetic structures and phylogeographic pat- terns of the two species.
基金Supported by the National Natural Science Foundation of China (Nos.40406028, 40706044)
文摘Mitochondrial cytochrome b (Cytb), one of the few proteins encoded by the mitochondrial DNA, plays an important role in transferring electrons. As a mitochondrial gene, it has been widely used for phylogenetic analysis. Previously, a 949-bp fragment of the coding gene and mRNA editing were characterized from Prorocentrum donghaiense, which might prove useful for resolving P. donghaiense from closely related species. However, the full-length coding region has not been characterized. In this study, we used rapid amplification of cDNA ends (RACE) to obtain full-length, 1 124 bp cDNA. Cytb transcript contained a standard initiation codon ATG, but did not have a recognizable stop codon. Homology comparison showed that the P. donghaiense Cytb had a high sequence identity to Cytb sequences from other dinoflagellate species. Phylogenetic analysis placed Cytb from P. donghaiense in the clade of dinoflagellates and it clustered together strongly with that from P. minimum. Based on the full-length sequence, we inferred 32 editing events at different positions, accounting for 2.93% of the Cytb gene. 34.4% (11) of the changes were A to G, 25% (8) were T to C, and 25% (8) were C to U, with smaller proportions of G to C and G to A edits (9.4% (3) and 6.2% (2), respectively). The expression level of the Cytb transcript was quantified by real-time PCR with a TaqMan probe at different times during the whole growth phase. The average Cytb transcript was present at 39.27±7.46 copies of cDNA per cell during the whole growth cycle, and the expression of Cytb was relatively stable over the different phases. These results deepen our understanding of the structure and characteristics of Cytb in P. donghaiense, and confirmed that Cytb in P. donghaiense is a candidate reference gene for studying the expression of other genes.
基金supported by the National Science and Technology Support Planning Project (2008BADB2B04-8-4)Natural Science Foundation of Hebei Province (C2008001308)
文摘[ Objective] To preliminarily explore the intraspecific relationship of sheep based on cytochrome b ( Cyt b) gene of mitochondrial DNA (mtDNA). [Method] The Cyt b gene sequences in 112 sheep individuals of two local sheep breeds were amplified by PCR. Then the amplified products were digested with EcoR I and analyzed by restriction fragment length polymorphism (RFLP). [ Result] As many as 56 samples from Tan sheep and 56 samples from Wadi sheep were detected. The results showed that the amplified Cyt b gene in 51 individuals of Tan sheep had one EcoR I restriction site and no EcoR I restriction site in other five individuals, thus the Cyt b gene in Tan sheep showed two restriction morphs; the Cyt b gene in all 56 individuals of Wadi sheep had one EcoR I restriction site and showed one restriction morph. [ Conclusion] The polymorphism of mitochondrial Cyt b gene in Tan sheep and Wadi sheep is poor, and the Cyt b gene in sheep breeds is very conservative. Therefore, using Cyt b gene as gene marker to study the intraspecific relationship of sheep has some limitations.
文摘Cyt b gene of North Sulawesi Tarsius sp., T. tumpara, T. sangirensis and T. tarsier (T. spectrum) had been partially sequenced. The homologous sequence of three groups had been compared to describe the phylogenetic position among them, as well as several other species accessed from the Genbank. Total DNA extracted from the muscular tissue had been obtained through tail cut sampling using the innuPREP DNA micro kit, and amplified using a pair of universal primer, L14841 and H15149. The size of the cyt b gene sequence amplified was 307 bp long. Sequence aligned using CLUSTAL-X program and diversity analysis were done using version 5.2.2. MEGA5 program. Genetic distance had been calculated by Tamura 3 parameter method and phylogenetic tree had been built using Neighbor-Joining and Maximum Likelihood methods. Genetic distance based on cyt b gene nucleotide was found from 0 to 0.240 with an average of 0.080. The phylogenetic tree constructed by Neighbor Joining and Maximum Likelihood methods indicated that T. tarsier, T. sangirensis and T. tumpara were closely related with Tarsius tarsier-complex, and distantly related with Cephalopachus bancanus and Carlito syrichta. The genetic distance and the phylogenetic tree had been constructed on the base of partial cyt b gene sequence of T. tarsier, T. sangirensis, T. tumpara and 5 other tarsier species and their accession. Those results are consistent with taxonomy based on morphology and vocal acoustic form.