尼罗罗非鱼和萨罗罗非鱼遗传生殖隔离的初步证据(英文)

罗非鱼类(Tilapiini)含3个属70余种,种间和属间颇易人工杂交,但尼罗罗非鱼(Oreochromis niloticus)和萨罗罗非鱼(Sarotherodon melanotheron)人工杂交难度大,产苗概率甚低,要获得数量足够的可用于生产的杂交子代相当困难。该文对这两种鱼及其正交(O.niloticus♀×S.melanotheron♂)和反交(S.melanotheron♀×O.niloticus♂)子代的头肾细胞的核型进行了比较。此外,采用同工酶电泳方法检测肾、肝、眼、肌肉、心中乳酸脱氢酶等4种同工酶的表型差异。4种遗传型罗非鱼具有相同的染色体二倍数(2n=44)和总臂数(NF=50),但各具不同的染色体类型,尼罗罗非鱼为3对近中着丝点染色体(sm)、12对近端着丝点染色体(st)和7对端着丝点染色体(t);萨罗罗非鱼为1对中间着丝点染色体(m)、2对sm、12对st和7对t;正反杂交子代表现为介于双亲之间的混合类型,为0.5对m、2.5对sm、12对st和7对t。在同工酶中,仅见肾脏乳酸脱氢酶电泳结果有清晰差异,尼罗罗非鱼出现5条谱带,萨罗罗非鱼3条,而杂交子代6条,且所有谱带的迁移率和活性均表现出多态性。据此初步认为,核型和同工酶方面的差异可能是导致这两种不同属罗非鱼生殖隔离的遗传原因,这些差异也可能为这两种(属)鱼的分类学提供新的遗传背景资料。     

Complete mitochondrial genome sequence of the Indian pipistrelle Pipistrellus coromandra (Vespertilioninae)

We characterized the complete mitogenome of Pipistrellus coromandra (Indian pipistrelle) for comparative analysis of mitogenomes and for resolving the phylogenetic relationship of four tribes in the subfamily Vespertilioninae. The mitogenome size of P. coromandra was 17,153?bp, with a control region and a typical set of 37 mitochondrial genes. The nucleotide composition of the P. coromandra mitogenome showed an AT bias with a nucleotide composition of 33.5% A, 30.7% T, 13.3% G, and 22.5% C. The mitochondrial protein-coding genes in P. coromandra use the standard start codon (ATN), two stop codons (TAA and AGA), and two incomplete stop codons (TA- and T--). The intertribal relationship of four tribes was highly resolved from the phylogenetic analysis of mitogenome sequences.     

Complete mitochondrial DNA sequences of the Nile tilapia (<Emphasis Type="Italic">Oreochromis niloticus</Emphasis>) and Blue tilapia (<Emphasis Type="Italic">Oreochromis aureus</Emphasis>): genome characterization and phylogeny applications

Cichlid fishes have played an important role in evolutionary biology and aquaculture industry. Nile tilapia (Oreochromis niloticus), blue tilapia (Oreochromis aureus) and Mozambique tilapia (Oreochromis mossambicus), the useful models in studying evolutionary biology within Cichlid fishes, are also mainly cultured species in aquaculture with great economic importance. In this paper, the complete nucleotide sequence of the mitochondrial genome for O. niloticus and O. aureus were determined and phylogenetic analyses from mitochondrial protein-coding genes were conducted to explore their phylogenetic relationship within Cichlids. The mitogenome is 16,625 bp for O. niloticus and 16,628 bp for O. aureus, containing the same gene order and an identical number of genes or regions with the other Cichlid fishes, including 13 protein-coding genes, two rRNA genes, 22 tRNA genes and one putative control region. Phylogenetic analyses using three different computational algorithms (maximum parsimony, maximum likelihood and Bayesian method) show O. niloticus and O. mossambicus are closely related, and O. aureus has remotely phylogenetic relationship from above two fishes.     

高桥仁蚧线粒体全基因组测序与分析

【目的】测定和分析半翅目(Hemiptera)仁蚧科(Aclerdidae)首个线粒体全基因组——高桥仁蚧Aclerda takahashii线粒体全基因组序列,并探讨与其他蚧虫类群的系统发育关系。【方法】基于Illumina测序技术进行高桥仁蚧线粒体全基因组测序,并进行生物信息学分析;基于已报道的15科31种半翅目昆虫的线粒体全基因组序列运用最大似然法(ML)和贝叶斯推断法(BI)构建半翅目系统发育树。【结果】高桥仁蚧线粒体基因组全长16 599 bp, AT含量高达84.51%。在该线粒体基因组中,缩减tRNA非常普遍, 10个tRNA缺失二氢尿嘧啶(DHU)臂或TΨC臂, tRNAser(S1)和tRNAser(S2)缺失DHU臂和TΨC臂。系统发育树显示, 与仁蚧科亲缘关系最近的是蚧科(Coccidae)。【结论】本研究报道了首个仁蚧科的线粒体基因组, 发现在高桥仁蚧线粒体基因组中存在普遍的tRNA缺臂现象, 为进一步系统地研究蚧虫线粒体基因组提供了数据支持。     

Complete mitochondrial genome of the Antarctic amphipod Gondogeneia antarctica (Crustacea, amphipod)

The complete sequence of the mitochondrial genome of the Antarctic amphipod Gondogeneia antarctica was determined to be 18,424 bp in length, and to contain 13 protein-coding genes (PCGs), 22 tRNA genes, and large (rrnL) and small (rrnS) rRNA genes. Its total A+T content is 70.1%. The G. antarctica mitogenome is the largest known among those of crustaceans, due to the existence of two relatively large intergenic non-coding sequences. The PCG arrangement of G. antarctica is identical to that of the ancestral pancrustacean ground pattern, although the tRNA arrangement differs somewhat. The complete mitogenome sequences of 68 species of pancrustacea have been added to the NCBI database, only 4 of which represent complete mitogenome sequences from amphipods. This is the first report of a mitogenome sequence of an Antarctic amphipod, and provides insights into the evolution of crustacean mitochondrial genomes, particularly in amphipods.     

The complete mitochondrial genome of Eriocheir japonica sinensis (Decapoda: Varunidae) and its phylogenetic analysis

The complete mitochondrial genome (mitogenome) can provide novel insights into understanding the mechanisms underlying mitogenome evolution. In this study, the complete mitogenome of Eriocheir japonica sinensis (Decapoda: Varunidae) was determined to be 16,378 bp, including 13 protein-coding genes (PCGs), two rRNA genes, 22 tRNA genes and a D-loop region. The AT skew of the E. j. sinensis mitogenome was slightly negative (−0.016), indicating a higher number of T compared with A nucleotides. The nucleotide composition of the mitogenome was also biased toward A + T nucleotides (71.6%). All PCGs were initiated by ATN codons. Eight of the 13 PCGs harbored the incomplete termination codon by T, or TA. All other tRNA genes displayed a typical clover-leaf structure of mitochondrial tRNA. The D-loop region of the E. j. sinensis mitogenome was 918 bp in length. Based on 13 PCGs, phylogenetic analysis confirmed the placement of E. j. sinensis within the Varunidae.     

Phylogenetic relationships between 21 species of three tilapiine genera Tilapia, Sarotherodon and Oreochromis using allozyme data

With the aim of detecting speciation events in Tilapia sensu lato , 24 enzyme loci were studied in eleven species of the genus Tilapia , four species fo the genus Sarotherodon , five species fo the genus Oreochromis and five other species belonging to similar genera ( Pelmatochromis, Chilochromis, Tylochromis, Hemichromis and Chromidotilapia ). The phylogenetic trees obtained show a clustering of species (except for Sarotherodon melanotheron ) according to their genera, i.e. Tilapia, Sarotherodon or Orechromis , which confirms the systematics adopted by Trewavas. The phylogenetic trees obtained by rooting with species belonging to similar genera confirm the hypothesis that mouthbrooders ( Sarotherodon and Oreochromis ) have a single origin, i.e. egg layers ( Tilapia ), and negate the hypothesis of multiple speciation of Peters and Berns.     

肺囊康定产生菌Glarea lozoyensis线粒体基因组序列的再分析

[目的] Glarea lozoyensis是抗真菌药物卡泊芬净的产生菌,其突变菌株ATCC 74030的线粒体基因组已被报道。我们此前的研究发现诱变剂能引起该菌某些细胞核基因的突变,但诱变剂是否也能引起线粒体DNA序列的改变并不清楚。[方法] 组装野生型菌株ATCC 20868的线粒体基因组,并与发表的突变型菌株ATCC 74030的线粒体基因组进行比较。通过PCR验证野生和突变菌株线粒体基因组间表现差异之处,并利用正确的线粒体基因组序列进行新的分析。[结果] 我们成功组装出野生型菌株ATCC 20868的线粒体基因组,通过比较其与发表的ATCC 74030的线粒体基因组序列,发现存在6处单核苷酸变异位点和2处具有长度差异的区域。然而,随后的PCR验证和序列比较并没有发现2个菌株间存在这些差异。最初观察到的碱基差异是因为发表的ATCC 74030线粒体基因组存在序列错误。有趣的是,在Glarea lozoyensis的线粒体基因组中,我们发现存在3个具有内含子的tRNA基因和1个rnpB基因。同时,该菌线粒体基因组中存在多种重复序列,在其线粒体和细胞核基因组间也存在明显的DNA片段重复事件。[结论] 诱变剂没有引起G. lozoyensis线粒体DNA的任何改变;发表的ATCC 74030的线粒体基因组存在序列错误。我们报道G. lozoyensis正确的线粒体基因组序列,并且发现该菌线粒体和细胞核基因组间频繁的基因交流。     

Complete mitochondrial genome sequence of the dragonet Callionymus curvicornis (Perciformes: Callionymoidei: Callionymidae)

We determined the complete mitochondrial genome (mitogenome) sequence of the dragonet Callionymus curvicornis. The total length of C. curvicornis mitogenome is 16,406 bp, which consists of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and 1 control region. It has the typical vertebrate mitochondrial gene arrangement. This is the first report of a complete mitochondrial genome in the fish suborder Callionymoidei.     

斑翅草螽线粒体基因组序列测定与分析

已经测定的昆虫线粒体基因组中, 直翅目草螽亚科的疑钩额螽Ruspolia dubia线粒体控制区长度最短, 仅70 bp。为此, 本研究采用L-PCR结合二次PCR扩增策略对另一种草螽亚科昆虫斑翅草螽Conocephalus maculates线粒体基因组序列进行了测定。序列注释发现: 斑翅草螽线粒体基因组序列全长15 898 bp, A+T含量为72.05%, 基因排列与典型的节肢动物线粒体基因组一致。全部蛋白质编码基因以典型的ATN作为起始密码子, 9个蛋白质编码基因具有完整的终止密码子, 其余4个以不完整的T作为终止信号。除trnS^AGN外, 其余21个tRNAs均可折叠形成典型的三叶草结构, 依照Steinberg等(1997)线粒体特殊tRNA结构类型-9, trnS^AGN的DHU臂形成一个7 nt环, 反密码子臂则长达9 bp, 含1个突起碱基, 而不是正常的5 bp。斑翅草螽与其他直翅目昆虫线粒体基因组的主要区别在于, 在trnS^UCN和nad1, nad1和trnL^CUN基因间各存在一段罕见的、大段的基因间隔序列, 长度分别为78 bp和360 bp。其中, 位于nad1和trnL^CUN之间的基因间隔序列N链可形成一个包含完整起始、终止密码子(ATT/TAA)、编码103个氨基酸的未知开放阅读框。同义密码子使用偏好与线粒体基因组编码的tRNA反密码子匹配情况无关, 但与密码子第3位点的碱基组成紧密相关; 相对密码子使用频率(relative synonymous codon usage, RSCU)大于1的密码子, 其第3位点全部是A或T。在已经测定的直翅目昆虫线粒体基因组tRNAs中, 均存在一定数量的碱基错配, 且以G-U弱配对为主, 表明G-U配对在线粒体基因组中可能是一种正常的碱基配对形式。本研究测定的斑翅草螽线粒体基因组序列, 和先前已经测定的直翅目线粒体基因组序列一起, 可以为重建直翅目的进化历史提供数据资源。     

栽培大豆和野生大豆线粒体基因组密码子使用偏性的比较分析

为分析栽培大豆和野生大豆线粒体基因组的密码子使用特征差异,该文以其线粒体基因组编码序列为研究对象,比较其密码子偏性形成的影响因素和演化过程。结果表明:(1)栽培大豆和野生大豆线粒体基因组编码区的GC含量分别为44.56%和44.58%,说明栽培大豆和野生大豆线粒体编码基因均富含A/T碱基。(2)栽培大豆和野生大豆线粒体基因组密码子第1位、第2位GC含量平均值与第3位GC含量的相关性均呈极显著水平,说明突变在其密码子偏性形成中的作用不可忽略; PR2-plot分析显示,在同义密码子第3位碱基的使用频率上,嘌呤低于嘧啶; Nc-plot分析中Nc比值位于-0.1～0.2区间的基因数占总基因数的95%以上;突变和选择等多重因素共同作用影响了大豆线粒体基因组编码序列密码子使用偏性的形成。(3)有20、21个密码子分别被确定为栽培大豆和野生大豆线粒体基因组编码序列的最优密码子,其中除丝氨酸TCC密码子外均以A或T结尾。综上结果认为,栽培大豆线粒体密码子偏性的形成受选择的影响要高于野生大豆,这可能是栽培大豆由野生大豆经长期人工栽培驯化的结果。     

Functional microsatellite and possible selective sweep in natural populations of the black-chinned tilapia Sarotherodon melanotheron (Teleostei, Cichlidae)

The Prolactin I (PrlI) gene is a key locus involved in fish osmotic regulation. Two microsatellites, PrlI GT and PrlI AC, are present in the promoter region of this gene in tilapias. One of these microsatellite is associated to PrlI gene expression and growth rate. Aquaria reared individuals homozygous for long microsatellite alleles at the PrlI AC locus expressed less PrlI in fresh water than fishes with other genotypes. To assess the occurrence of selection acting on these microsatellites we carried out a survey of their variability compared with four others microsatellites in natural populations. Samples of two tilapia species were studied, Oreochromis niloticus (6 samples) a typically freshwater species inhabiting osmotically stable environments and Sarotherodon melanotheron (5 samples) a brackish water species obliged and able to adapt very rapidly to any salinity changes. For both species the different populations studied exhibited a high amount of differentiation (all F(st) value were statistically significant) at every loci. Only one locus, PrlI AC, was monomorphic for the same allele in all S. melanotheron populations. We have hypothesized that this outlier locus with its unique allele could have experienced a selective sweep that took place in the early stages of the species origin. S. melanotheron represents an example of adaptation (to fluctuant salinity environment) acting indirectly on gene product through its promoter.     

Mitochondrial genome of the cotton bollworm Helicoverpa armigera (Lepidoptera: Noctuidae) and comparison with other Lepidopterans

We present the complete sequence of the mitochondrial genome (mitogenome) of the cotton bollworm Helicoverpa armigera. The 15,347-bp mitogenome of H. armigera was arranged in the same order described for all other sequenced lepidopterans, which differs from the most common type found in insects, due to the movement of trnM to a position 5'-upstream of trnI. The gene overlap in the H. armigera mitogenome is totally 23 bp in six locations. The H. armigera mitogenome has a total of 175 bp of intergenic spacer sequences spread over 14 regions ranging in size from 1 to 45 bp. The nucleotide composition of the whole mitogenome of H. armigera is highly A+T biased, accounting for 80.97%, with a slightly positive AT skewness and negative GC skewness, indicating the occurrence of more A than T, C more than G. The protein-encoding genes have typical mitochondrial start codons, except for cox1, which contains the unusual CGA. The cox1, cox2, and nad4 genes have incomplete stop codons (T). The lrRNA and srRNA genes are 1395 and 794-bp long, respectively. All tRNAs have a typical cloverleaf structure of mitochondrial tRNAs, except for trnS1(AGN), the dihydrouridine arm of which could not form a stable stem-loop structure. The H. armigera A+T-rich region contains a conserved structure combining the motif ATAGA and a 19-bp poly-T stretch, but absence of the 9-bp poly-A element upstream of trnM.     

Infection patterns of Myxobolus heterospora in two tilapia species (Teleostei: Cichlidae) and its potential effects

A Myxobolus heterospora (Baker, 1963) infection was found in 2 euryhaline tilapia species, Sarotherodon melanotheron melanotheron (Rüppel, 1853) and Tilapia zillii (Gervais, 1852), from a brackish water lake, Lake Nokoué (Benin, West Africa). The histology and ultrastructure of different levels of infection in intestinal connective tissues and wall tissues is described. A total of 391 S. melanotheron melanotheron and 222 T. zillii were examined from October 1987 to October 1989. M. heterospora was found throughout the study period, with a total prevalence of 42.19 and 26.57% for S. melanotheron melanotheron and T. zillii respectively. There was a statistically significant difference in occurrence as a function of season in S. melanotheron melanotheron but not in T. zilli, and there was a significant difference for size and sex in the former and for sex in the latter. M. heterospora induces total destruction of the intestine structure and probably leads to osmoregulatory disturbance. Further investigations of this myxosporean infection are necessary to determine its real effect on the host, since host survival and osmoregulatory rate have not yet been assessed.     

The mitogenome of Onchocerca volvulus from the Brazilian Amazonia focus

We report here the first complete mitochondria genome of Onchocerca volvulus from a focus outside of Africa. An O. volvulus mitogenome from the Brazilian Amazonia focus was obtained using a combination of high-throughput and Sanger sequencing technologies. Comparisons made between this mitochondrial genome and publicly available mitochondrial sequences identified 46 variant nucleotide positions and suggested that our Brazilian mitogenome is more closely related to Cameroon-origin mitochondria than West African-origin mitochondria. As well as providing insights into the origins of Latin American onchocerciasis, the Brazilian Amazonia focus mitogenome may also have value as an epidemiological resource.     

Complete mitochondrial genome of black porgy Acanthopagrus schlegelii (Perciformes, Sparidae)

Black porgy, Acanthopagrus schlegelii, is a marine protandrous hermaphrodite and belongs to one of the most important species commercialized for food in various areas of Asia. In this study, the complete mitochondrial genome of A. schlegelii has been determined. The mitogenome was 16,649 bp in length and contained 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and 2 non-coding regions. It shared 90.2%, 82.3%, and 82.1% mitogenome sequence with Acanthopagrus latus, Parargyrops edita, and Pagrus major, respectively.     

社鼠（Niviventer confucianus）线粒体基因组全序列分析

社鼠（Niviventer confucianus）属于啮齿目（Rodentia）、鼠科（Muridae）、白腹鼠属（Niviventer）,关于该物种的分子系统学研究极少。为获取社鼠线粒体基因组全序列,提取其基因组总DNA,参照近缘物种线粒体基因组全序列设计34对特异性引物,利用PCR扩增全部片段后进行测序,之后对其基因组组成及结构特点进行了初步分析。结果表明,社鼠线粒体基因组全序列长16 281 bp（GenBank收录号：KJ152220）,包含22个tRNA基因、13个蛋白质编码基因、2个rRNA基因和1个非编码控制区;基因组核苷酸组成为34.0%A、28.6%T、24.9%C、12.5%G。将所得序列与社鼠近缘物种（川西白腹鼠、小家鼠、褐家鼠）的线粒体全基因组进行比较,结果显示,四个物种的线粒体基因组虽然在基因组大小、部分tRNA二级结构、部分蛋白质编码基因的起始或终止密码子及控制区长度和碱基组成上有差异,但基因组结构和序列特征方面都具有较高的相似性。四个物种线粒体全基因组间的遗传距离显示,社鼠与川西白腹鼠距离最近,而与小家鼠距离最远。该研究为利用线粒体全基因组信息进行啮齿类分子系统学研究提供了有价值的资料。     

Mitochondrial genome of Onychostoma lini (Teleostei, Cypriniformes)

The complete mitogenome sequence of a vulnerable species Onychostoma lini was determined using polymerase chain reaction and directly sequenced with primer walking method. The complete mitogenome was 16,595?bp in length, containing 37 genes of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a control region (D-loop). The gene order and composition of O. lini was similar to most other fishes. The descending order of the base composition on heavy strand was 31.6% A, 27.9% C, 24.6% T, and 15.9% G, with a relatively lower level of G and a slight AT bias of 56.2%. The codon usage followed the typical vertebrate mitochondrial pattern (ATG or GTG for start codon and TAA or TAG for stop codon). The complete mitogenome sequence of O. lini provides fundamental data for further conversation genetics and captive breeding studies on this species.