Molecular phylogeny of Sinocyclocheilus (Cypriniformes : Cyprinidae) inferred from mitochondrial DNA sequences

More than 10 species within the freshwater fish genus Sinoncyclocbeilus adapt to caves and show different degrees of degeneration of eyes and pigmentation. Therefore, this genus can be useful for studying evolutionary developmental mechanisms, role of natural selection and adaptation in cave animals. To better understand these processes, it is indispensable to have background knowledge about phylogenetic relationships of surface and cave species within this genus. To investigate phylogenetic relationships among species within this genus, we determined nucleotide sequences of complete mitochondrial cytochrome b gene (1140 bp) and partial ND4 gene (1032 bp) of 31 recognized ingroup species and one outgroup species Barbodes laticeps. Phylogenetic trees were reconstructed using maximum parsimony. Bayesian, and maximum likelihood analyses. Our phylogenetic results showed that all species except for two surface species S. jii and S. macrolepis clustered as five major monophyletic clades (I, II, III, IV, and V) with strong supports. S. jii was the most basal species in all analyses, but the position of S. macrolepis was not resolved. The cave species were polyphyletic and occurred in these five major clades. Our results indicate that adaptation to cave environments has occurred multiple times during the evolutionary history of Sinocyclocheilus. The branching orders among the clades I, II, III, and IV were not resolved, and this might be due to early rapid radiation in Sinocyclocheilus. All species distributed in Yunnan except for S. rhinocerous and S. hyalinus formed a strongly supported monophyletic group (clade V), probably reflecting their common origins. This result suggested that the diversification of Sinocyclocheilus in Yunnan may correlate with the uplifting of Yunnan Plateau. © 2005 Published by Elsevier Inc.

Exploring factors shaping population genetic structure of the freshwater fish Sinocyclocheilus grahami (Teleostei, Cyprinidae)

Phylogeographical analyses on Sinocyclocheilus grahami samples from seven localities within the Lake Dianchi Basin in China were conducted to explore the main factors shaping population structure within this species. Phylogenetic and network analyses reve

The complete mitochondrial genomes of two species from Sinocyclocheilus (Cypriniformes: Cyprinidae) and a phylogenetic analysis within Cyprininae

We determined the complete mitochondrial DNA sequences for two species of surface- and cave-dwelling-cyprinid fishes, Sinocyclocheilus grahami and S. altishoulderus. Sequence comparison of 13 protein-coding genes shows that the mutation pattern of each single gene is quite similar to those of other vertebrate animal species. Analysis of the ratios of Ka/Ks at these loci between Sinocyclocheilus and two other cyprinid species (Cyprinus carpio and Procypris rabaudi) show that Ka/Ks ratios are differed, consistent with purifying selection and variation in functional constraint among genes. Bayesian analysis and maximum likelihood analysis of the concatenated mitochondrial protein sequences for 14 cyprinid taxa support the monophyly of the family Cyprininae, and further confirm the monophyly of the genus Sinocyclocheilus. The two Sinocyclocheilus species fall within the Cyprinion-Onychostoma lineage, including Cyprinus, Carassius, and Procypris, rather than among the Barbinae, as previously suggested on morphological grounds.

Relaxed purifying selection of rhodopsin gene within a Chinese endemic cavefish genus Sinocyclocheilus (Pisces: Cypriniformes)

The cyprinid fish genus Sinocyclocheilus, as the most cavefish rich genus, includes many species showing striking adaptation to caves and convergent reduction or even loss of eyes and pigmentation. RH1 is responsible for dim vision. In order to explore the evolution of RH1 gene in this genus, we sequenced the complete gene from 28 individuals of 16 representative species of Sinocyclocheilus, with cave and surface species included. Phylogenetic analyses supported the monophyly of Sinocyclocheilus and polyphyly of the cave species. Codon models implemented in PAML were used to infer the evolution of RH1. We found that Sinocyclocheilus had a significantly higher evolutionary rate for amino acids than other cyprinid fishes compared, which might be the result of relaxation of purifying selection and could be ascribed to cave habit of this genus. In contrast to previous hypotheses, both cave and surface lineages exhibited a similar rate of molecular evolution, so the RH1 of cave species may still be functional, although these species were highly adapted to cave environment. Two amino acid substitutions (D83G and E122V) that were not reported before were found, which may be useful for site-directed mutagenesis in the future.

Bayesian mixed models and divergence time estimation of Chinese cavefishes (Cyprinidae : Sinocyclocheilus)

The genus Sinocyclocheilus is distributed in Yun-Gui Plateau and its surrounding region only, within more than 10 cave species showing different degrees of degeneration of eyes and pigmentation with wonderful adaptations. To present, published morphological and molecular phylogenetic hypotheses of Sinocyclocheilus from prior works are very different and the relationships within the genus are still far from clear. We obtained the sequences of cytochrome b (cyt b) and NADH dehydrogenase subunit 4 (ND4) of 34 species within Sinocyclocheilus, which represent the most dense taxon sampling to date. We performed Bayesian mixed models analyses with this data set. Under this phylogenetic framework, we estimated the divergence times of recovered clades using different methods under relaxed molecular clock. Our phyloegentic results supported the monophyly of Sinocyclocheilus and showed that this genus could be subdivided into 6 major clades. In addition, an earlier finding demonstrating the polyphyletic of cave species and the most basal position of S. jii was corroborated. Relaxed divergence-time estimation suggested that Sinocyclocheilus originated at the late Miocene, about 11 million years ago (Ma), which is older than what have been assumed.

六种鱼巴亚科鱼类线粒体细胞色素b 基因序列分析

测定了鱼巴亚科云南光唇鱼( Acrossocheilus yunnanensis) 、宽头四须鱼巴( Barbodes laticeps) 、抚仙金线鱼巴 ( Sinocyclocheilus tingi) 和滇池金线鱼巴( Sinocyclocheilus grahami) 4 种鱼类线粒体细胞色素b 基因DNA 序列402 bp ,结合已知的云南倒刺鱼巴( S pinibarb denticulatus yunnanensis) 和细尾长臀鱼巴( Mystacoleucus lepturus) 的同源 序列,组成1 个6 种代表鱼巴亚科5 属鱼类的数据集. 选用已知的云南鲴( Xenocypris yunnanensis) 作为外群,采用 邻接法、最大简约法和最大似然法构建了分子系统树. 结果显示: 倒刺鱼巴属( S pinibarbus) 和光唇鱼属 ( Acrossocheilus) 有较近的亲缘关系,四须鱼巴属( Barbodes) 和长臀鱼巴属( Mystacoleucus) 有较近的亲缘关系,而金 线鱼巴属( Sinocyclocheilus) 和它们的关系不能确定. 上述结果与它们的地理分布基本吻合.

滇池金线鲃形态度量学分析(Cypriniformes:Cyprinidae)

运用多变量形态度量学和框架结构形态学的方法,测量了采自滇池流域6个不同地点的149尾滇池金线鲃(Sinocyclocheilus grahami)的标本.应用多变量形态度量学分析,选择了20个框架结构性状和19个常规性状,进行主成成分分析.主成成分分析结果的散布图显示,6个不同地点的标本聚在一起没有分开,表明滇池金线鲃的各居群之间在可数性状和可量性状上均未表现出明显的差异,说明滇池金线鲃在形态上还未发生明显的种下分化.

池塘养殖环境下滇池金线鲃仔稚鱼的食性转化与生长

下载PDF阅读器2008年3月-2009年3月,把35 000尾滇池金线鲃(Sinocyclocheilus grahami)仔稚鱼分别饲养于3个池塘进行对比饲养研究.密度分别是:P1为208尾/m3;P2为167尾/m3;P3为41尾/m3.饲养期间采用相同的管理措施.每天数据收集采用:在仔鱼孵化后的5～16d的每天8:00和18:00从每个育苗池中捞取5～8尾仔鱼进行测量分析.仔鱼开口30d后,每月从培育池各捞取15尾,测量全长和体重.研究发现,滇池金线鲃仔鱼的开口时间为孵化后的5 d,混合营养期3～5d,这与初孵的演池金线鲃仔鱼的全长和卵黄囊较大有关.在容易造成仔鱼大量死亡的混合营养期,通过采用浆状物-轮虫-人工混合饲料的方式,大幅度提高了滇池金线鲃仔稚鱼的存活率,孵化一年后的滇池会线鲃稚鱼存活率可达82.7%.经过一周年的饲养,滇池金线鲃稚鱼的体重由(0.027±0.01)g(0.003～1.22)增长到(8.83±0.54)g (3.7～16.7),月均增重为0.73 g;全长由(15.8±0.30)mm (11.5～20.0)增长到(91.6±1.67)mm (75.0～16.0),全长月均增长6.32 mm.滇池金线鲃稚鱼全年全长的增长呈线性相关,y=9.82+7.05month(R2=0.9891);全年体重的增长呈指数关系,y=0.0158month2.54(R2=0.9939).

抚仙金线鲃人工繁殖与鱼苗培育技术

抚仙金线鲃(Sinocyclocheilus tingi)是抚仙湖的特有种.2009年3-4月,有4次繁殖试验取得了成功.先后试验了40尾雌鱼和20尾雄鱼,成功催产19尾雌鱼和15尾雄鱼,分别占雌雄鱼的47.5%和75.0%.获得鱼卵25 547粒,并实施干法受精.有16810粒受精,平均受精率为65.8%.孵化出鱼苗约6040尾,平均孵化率为23.6%.经过20目的饲养,仔鱼存活3 056尾,存活率为50.6%.抚仙金线鲃较低的催产率,可能是生殖功能紊乱所致:但也不排除是人工营造的条件离其自然环境需求尚有距离.要使抚仙金线鲃成为鱼鱇<鱼良>白鱼(Anabarilius grahami)之后又一当地特色养殖鱼种,突破其人工繁殖瓶颈,培育高品质鱼苗是必由之路.突破其人工繁殖,还可为研究抚仙金线鲃的生活史和保护该物种免于灭绝奠定良好基础.

云南滇池濒危特有种滇池金线鲃人工繁殖初报

滇池金线鲃(Sinocyclocheilus grahami)是滇池湖泊生态系统的指示物种和特有种.因水质污染和外来物种入侵等因素的影响,该鱼类自1986年起就从湖体中消失,仅有湖周围的少数龙潭中尚保存有少量滇池金线鲃.至2007年3月初,有两次繁殖试验取得了成功.先后试验了5尾雌鱼和6尾雄鱼,获得鱼卵约1 600粒,并实施干法受精.约有1 320粒受精,平均受精率为73%.孵化出鱼苗约480尾,平均孵化率为36%.经10天饲养,约有95%以上的鱼苗存活,体长达8-12 mm.滇池金线鲃人工繁殖成功的意义有三点:能有效保护该物种免于灭绝;繁殖的鱼苗放归湖泊合适水域,将有助于恢复滇池的土著生物多样性;有助于推动当地水产养殖业从非土著鱼类养殖向土著鱼类养殖的方向转变.

广西盲鱼一新种及其系统关系分析(鲤形目:鲤科:鲃亚科)

经鉴定, 采自广西天峨县溶洞的盲鱼为金线鲃属一新种, 依形态特征命名为叉背金线Sinocyclocheilus furcodorsalis sp.nov.根据主要特征分析认为:新种适应洞穴环境相关性状特化程度大致与鸭嘴金线鲃相当;新种及其若干近似种的物种形成, 是营半穴居生活的类似长须金线鲃的祖先适应辐射的结果。

贝叶斯联合模型与中国洞穴鱼类分化时间的估算(鲤科:金线鲃属)

金线鲃属分布于中国云贵高原及周边地区,包括10多种适应于洞穴生活、具有不同程度眼睛和色素退化的典型洞穴鱼类.迄今为止,金线鲃属的系统发育关系还存在很大争议.我们获得了34种金线鲃属鱼类及外类群的细胞色素b和ND4基因序列,用贝叶斯联合模型分析数据,重建了金线鲃属的系统发育关系;并用松散分子钟估算了本属及内部分支的起源时间.金线鲃属的单系性得到强烈的支持,本属可分为6个分支.此外,本研究结果还支持洞穴物种的多系起源假说以及季氏金线鲃(Sinocyclocheilus jii)的基部位置.松散分子钟估算表明,

广西溶洞内生活的盲鱼——金线鲃属一新种

<正> 本文记述的金线鲃属一新种——鸭嘴金线鲃Sinocyclocheilus anatirostris, sp. nov.发现于广西凌云和乐业两地的溶洞内。这一种鱼由于长期在黑暗的洞穴环境里生活,产生了一系列的适应性变化,而与金线鲃属的已知各个种有十分显著的区别:鲜活鱼体呈半透明,无斑点,体侧沿纵轴隐约可见一条浅粉红色条纹;身体裸露,或残留少数退化的鳞片,侧线管穿孔于皮褶上,眼退化,仅留痕迹;吻部长而平扁,形似鸭嘴;额骨前端有一小嵴,突出于盲眼痕迹之上方;鳔后室退化呈细管状。尽管如此,而其它性状均与金线

Distinct Evolutionary Patterns Between Two Duplicated Color Vision Genes Within Cyprinid Fishes

We investigated the molecular evolution of duplicated color vision genes (LWS-1 and SWS2) within cyprinid fish, focusing on the most cavefish-rich genus-Sinocyclocheilus. Maximum likelihood-based codon substitution approaches were used to analyze the evolution of vision genes. We found that the duplicated color vision genes had unequal evolutionary rates, which may lead to a related function divergence. Divergence of LWS-1 was strongly influenced by positive selection causing an accelerated rate of substitution in the proportion of pocket-forming residues. The SWS2 pigment experienced divergent selection between lineages, and no positively selected site was found. A duplicate copy of LWS-1 of some cyprinine species had become a pseudogene, but all SWS2 sequences remained intact in the regions examined in the cyprinid fishes examined in this study. The pseudogenization events did not occur randomly in the two copies of LWS-1 within Sinocyclocheilus species. Some cave species of Sinocyclocheilus with numerous morphological specializations that seem to be highly adapted for caves, retain both intact copies of color vision genes in their genome. We found some novel amino acid substitutions at key sites, which might represent interesting target sites for future mutagenesis experiments. Our data add to the increasing evidence that duplicate genes experience lower selective constraints and in some cases positive selection following gene duplication. Some of these observations are unexpected and may provide insights into the effect of caves on the evolution of color vision genes in fishes.