大鳍鱊基于细胞色素b基因序列的遗传变异及生物地理过程

对采集于长江水系、黑龙江水系及海南岛的36尾大鳍(Acheilognathus macropterus)的细胞色素b基因序列进行了研究分析。发现有须个体和无须个体在分子系统树中处于混合分布状态,各个体相互间遗传变异远小于与外类群(A.chankaensis、A.tokinensis)间差异,统计了其主要形态度量数据,也显示各主要性状数据无显著差异,结果均支持有须个体和无须个体(曾经被鉴定为A.taenianalis)为同一物种,A.taenianalis为A.macropterus的同物异名。序列分析显示,36个个体明显聚合成5个大的分支,其中clade1分支全部由黑龙江水系类群组成,clade5分支由海南岛的1个个体组成,长江水系的所有个体分散在clade2、clade3、clade4这三个分支中,显示出一定的地理相关性。在clade2、3、4中,clade2包括了长江上游的5个个体和长江中游的2个个体,同时还包括了黑龙江的2个个体;clade3包括了中游的2个个体;clade4包括了中游的12个个体,三个分支间又存在明显的遗传变异率(均>5%),从21个个体在三个分支中的分布情况来看,三者间这种较大的遗传变异率不能由地理隔离解释,故推测,造成同一水系的A.macropterus间出现较明显遗传分化的原因可能与其特殊的性选择生殖方式有关,该生殖方式限制了不同生殖集群间同种鱼类的基因交流。基于系统分支图,计算了各分支间的遗传距离,由结果推测大鳍的生物地理过程为:海南岛水系类群同大陆类群较早产生隔离,黑龙江水系类群由长江水系类群在晚近时期向北扩散形成。       

Genetic diversity and the biogeographical process of Acheilognathus macropterus revealed by sequence variations of mitochondrial cytochrome b gene

In this study, thirty-six individuals of Acheilognathus macropterus were collected from the Heilongjiang River, the Yangtze River, and the Nandujiang River. Partial mitochondrial cytochrome b gene region (636 base pair) was sequenced to these samples and 22 haplotypes were found. With A. chankaensis and A. tokinensis as outgroups, their relationships were analyzed. The p-distances were calculated with Mega software and a molecular phylogenetic tree was constructed using the neighbor-joining (NJ) method. The proportions of main morphological characters were compared as well. P-distances showed that the genetic differences in A. macropterus samples were far smaller than those between these samples and the outgroups. The molecular phylogenetic tree shows that samples with barbels and those without barbels were intermingled. There was no distinctive difference in proportions of morphological characteristics among them. These results suggested that samples with barbels and those without barbels (formally identified as A. taenianalis) are the same species; A. taenianalis is synonymous with A. macropterus. The thirtysix individuals were grouped into five clades and the positions of the samples in the clades were correspondingly grouped within their geographical distributions. Among the five clades, clades 1 and 5 included samples from the Heilongjiang River and Nandujiang River respectively. The samples from the Yangtze River scattered into clades 2, 3, and 4. There were distinctive genetic differences (>5%) among them. Interestingly, the distributions of the 21 samples in these three clades were not correlated to their geographical distributions. It is postulated that these genetic differences were due to the bitterlings’ mating choice mechanism, the prozygotic isolation. The genetic differences between the fish from Nandujiang River and those from the mainland indicated that they were separated early. However, the small genetic differences among the samples and the positions of the fish from the Heilonjiang River in the molecular phylogenetic tree indicate that fish in Heilongjiang River might have dispersed from the Yangtze River to that area much later. __________ Translated from Acta Hydrobiologica Sinica, 2006, 39(2): 134–140 [译自: 水生生物学报]     

草鱼野生群体遗传变异的微卫星分析

利用12个微卫星标记, 对来自长江水系(邗江、吴江、九江、石首、木洞和万州)、珠江水系(肇庆)和黑龙江水系(嫩江)的8个草鱼野生地理群体进行了遗传多样性及遗传结构等分析。遗传多样性分析显示, 12个微卫星位点均为高度多态位点(PIC=0.755~0.930), 8个草鱼野生群体显示出较高的遗传多样性水平(Ho=0.839~0.893), 其中长江水系的6个群体和肇庆群体的多样性水平高于嫩江群体。瓶颈效应分析显示, 嫩江、肇庆群体及2个长江上游群体(木洞、万州)近期出现了瓶颈效应, 群体数量发生下降。群体间遗传分化指数F^ST及AMOVA分析显示, 群体间出现极显著遗传分化(P<0.01), 整体分化水平较低(F^ST<0.05)。遗传距离分析结果显示, 长江水系的6个群体与肇庆群体遗传距离较近, 与嫩江群体较远; 基于此的UPGMA聚类树显示, 长江水系下游、中游和上游的群体依次聚类, 然后与肇庆群体聚类, 最后与嫩江群体聚类, 遗传距离与地理距离呈现出较强的正相关性。遗传结构分析显示, 所有样本被划分为5个理论群, 肇庆和嫩江群体中个体的遗传结构相对独立, 而长江上游、中游和下游群体中个体的遗传结构则存在一定程度的混杂。综上所述, 中国草鱼野生资源具有较高的遗传多样性, 地理群体间存在遗传分化, 具有进一步遗传改良的潜力; 但部分群体出现的瓶颈效应也需要引起重视。     

长江朱杨江段和沱江富顺江段鱼类体内16种多环芳烃的含量

于2010年9-11月在长江朱杨江段采集到9种鱼类标本, 分别为瓦氏黄颡鱼(Pelteobagrus vachelli Richardson)、圆筒吻 (Rhinogobio cylindricus Gnther)、鲤(Cyprinus carpio Linnaeus)、鲫(Carassius auratus Linnaeus)、大眼鳜(Siniperca kneri Garman)、铜鱼(Coreius heterodon Bleeker)、圆口铜鱼(Coreius guichenoti Sauvage et Dabry)、大鳍鳠(Mystus macropterus Bleeker)和鲇(Silurus asotus Linnaeus); 在该江段上游支流沱江富顺江段采集到6种鱼类标本, 分别为鲫、黄颡鱼(Pelteobagrus fulvidraco Richardson)、鲤、大眼鳜、大鳍鳠和鲇, 每种鱼的样本量为6-11尾, 共计192尾。采用快速溶剂萃取及气相色谱法对鱼体中的16种多环芳烃(PAHs)含量进行了检测。结果显示, 在两个江段的各种鱼体样本中均检测到了多种多环芳烃的存在。在长江干流朱杨江段所采集到的9种鱼中瓦氏黄颡鱼体内多环芳烃总量(PAHs)最高, 其含量为(2803.78 215.37) ng/g; 鲇鱼体内PAHs最低, 其含量为(515.8638.80) ng/g。在沱江富顺江段采集到的6种鱼中鲫体内PAHs最高, 为(8498.571128.22) ng/g; 鲇鱼体内PAHs最低, 其含量为(1295.0569.69) ng/g。采集自长江朱杨段和沱江富顺段两采集地的相同种类有5种, 富顺段5种鱼体内PAHs均高于朱杨段同种类鱼体内的含量; 除大眼鳜外, 其余4种鱼的差异均达到显著水平。富顺江段鱼类体内高分子量多环芳烃比例较高, 而朱杨江段鱼类体内富集的低分子量多环芳烃和中分子量多环芳烃的比例较高。通过讨论认为, 长江朱杨段及其支流沱江富顺段的鱼体均受到了多环芳烃的污染, 并且沱江鱼类受多环芳烃的污染程度高于长江干流朱杨段鱼类。此外, 沱江富顺段鱼体所含的高分子量多环芳烃组成百分比高于长江干流朱杨段的鱼体, 但其中、低分子量多环芳烃组成百分比相对于干流鱼类较低, 可能的原因是两个江段多环芳烃的污染源不同。       

我国草鱼野生群体D-Loop序列遗传变异分析

利用线粒体DNA的D-Loop区序列, 对来自长江水系(邗江、吴江、九江、石首、木洞和万州)、珠江水系(肇庆)和黑龙江水系(嫩江)的8个草鱼野生群体开展了遗传变异分析。在424尾鱼中检测到34个变异位点, 34个单倍型, 单倍型多样性介于0.4740.708。群体间Kimura双参数遗传距离介于0.00200.0049。长江下游3个群体间遗传距离最近, 遗传分化不显著(P0.05); 肇庆群体与长江上游3个群体遗传距离较近, 与九江群体遗传分化不显著(P0.05); 嫩江群体与长江上游2个群体遗传距离较近, 与万州群体遗传分化不显著(P0.05)。遗传距离与地理距离存在极显著正相关(R=0.61, P0.01)。分子方差分析显示, 不同流域间遗传变异占总变异26.24%, 差异极显著(P0.01)。34个单倍型分为2个分支, 分化极显著(FST=0.644, P0.01), 推测分化时间为第四纪更新世纪晚期。       

Genetic Relationship of Chinese and Japanese Gamecocks Revealed by mtDNA Sequence Variation

Cockfighting has a very long history dating back to as early as 2500 years ago in China. Cockfighting was intertwined with human cultural traditions, helped disperse chickens across the world, and influenced the subsequent breed selection. Therefore, tracing the origin of gamecocks could mirror the distribution of the cockfighting culture. In this study, we compared the available mtDNA control region sequences in Chinese and Japanese gamecocks to test the recently proposed hypothesis behind the dual origin of the Japanese cockfighting culture (from China and Southeast Asia independently). We assigned gamecock mtDNAs to different matrilineal components (or phylogenetic clades) that emerged from the phylogenetic tree and network profile, and compared the frequency differences between Chinese and Japanese gamecocks. Among the six clades (A–F) identified, Japanese gamecocks were most frequently found in clades C and D (74%, 32/43), whereas more than half of the Chinese gamecock samples (69%, 35/51) were grouped in clades A and B. Haplotypes in Japanese gamecocks assigned to clades A, B, and E were either shared with those of the Chinese samples or differed from the close Chinese types by no more than a three-mutation distance. This genetic pattern is in accordance with the proposed dual origin of Japanese gamecocks but has left room for single origin of Japanese gamecocks from China. The genetic structure of gamecocks in China and Japan might also be influenced by subsequent breed selection and conservation after the initial gamecock introduction.     

基于线粒体细胞色素b基因全序列的海南长臀鮠南渡江种群遗传变异分析

测定了海南南渡江15尾海南长臀鮠(Cranoglanis bouderius multiradiatus)的cytb基因全序列1138bp,发现3个可变位点和1个简约信息位点,共检测到4种单倍型。海南长臀鮠Cytb基因具有典型的起始密码子(ATG)和不完全终止密码子(T^**),共编码379个氨基酸,密码子第三位点G的含量仅2.9%,而C和A的含量分别为39.1%和38.5%,在第二位点上T的使用频繁高达41.3%,表明cytb基因在密码子碱基的使用具有偏倚性。海南长臀鮠基于Kimura-2-parameter模型的单倍型间遗传距离为0.0009～0.0017,在NJ系统树中没有明显的谱系结构,单倍型多样性(0.600)和核苷酸多样性(0.0006)都较低,表明海南长臀鮠遗传多样性非常贫乏,应及时采取有效措施保护海南南渡江种群。     

Native bighead carp Hypophthalmichthys nobilis and silver carp Hypophthalmichthys molitrix populations in the Pearl River are threatened by Yangtze River introductions as revealed by mitochondrial DNA

Bighead carp Hypophthalmichthys nobilis and silver carp Hypophthalmichthys molitrix have been two economically important aquaculture species in China for centuries. In the past decades, bighead and silver carp have been introduced from the Yangtze River to many river systems in China, including the Pearl River, in annual, large-scale, stocking activities to enhance wild fisheries. Nonetheless, few studies have assessed the ecological or genetic impacts of such introductions on native conspecific fish populations. An mtDNA D-loop segment of 978 bp from 213 bighead carp samples from 9 populations and a 975 bp segment from 204 silver carp samples from 10 populations were obtained to evaluate genetic diversity and population integrity. Results from a haplotype network analysis revealed that most haplotypes of the Pearl River clustered with those of Yangtze River origin and only a small proportion were distinct, suggesting that both the native Pearl River bighead and silver carp populations are currently dominated by genetic material from the Yangtze River. The genetic diversity of Pearl River populations is high in both species because of this inter-population gene flow, but the diversity of native Pearl River populations is low. To preserve the native genetic diversity, stocking of non-native fingerlings should cease immediately and native Pearl River bighead and silver carp fish farms should be established. This research demonstrates the danger to native biodiversity across China because of the substantial, ongoing stock-enhancement activities without prior genetic assessment.     

诱导大鳍鱯和长吻鮠排卵过程中血清GTH水平的变化

繁殖期从嘉陵江收集性成熟的大鳍■ 和长吻 野生亲鱼,用Ｌｉｎｐｅ方法（即ＬＨＲＨ－Ａ加多巴胺Ｄ２受体拮抗剂地欧酮）或传统的ＬＨＲＨ—Ａ加脑垂体的方法进行催产,定时取血样,用放射免疫方法测定催产过程中血清ＧＴＨ水平的变化,进一步证实鲇形目鱼类ＧＴＨ的分泌受到下丘脑分泌的促性腺激素释放激素ＧｎＲＨ和多巴胺的双重调节;排卵和产卵也是以血清ＧＴＨ的急剧升高为先导的,而最终能否排卵还有赖于血清ＧＴＨ峰是否超过“排卵阈值”。尽管催产后的大鳍 和长吻 雄鱼血清ＧＴＨ水平也有一个高峰出现,但血清ＧＴＨ水平升高幅度都大大低于雌鱼,这种现象在硬骨鱼类可能具有普遍性。     

基于G-SSR和EST-SSR标记的鲫6个群体遗传结构分析

研究同时利用非编码区和编码区微卫星标记(G-SSR和EST-SSR)分析黑龙江、长江、奉化江及淮河水系共6个野生鲫(Carassius auratus)群体的遗传多样性及遗传结构, 并比较2类不同来源SSR用于鲫群体遗传多样性分析的差异。8个G-SSR标记在6个鲫群体中检测到173个等位基因, 平均N_a、N_e、H_o、H_e以及PIC分别为22、12.9、0.769、0.893和0.879, 群体间F_st值介于0.008—0.085, 其中来自黑龙江水系的2个群体与其余水系的所有群体均达到或接近于中等程度的遗传分化, 而长江、奉化江和淮河水系4个群体间的遗传分化程度不明显。Nei’s遗传距离介于0.203—0.701; 根据遗传距离所绘制的UPGMA聚类图将6个鲫群体划分为2个大分支, 其中来自黑龙江水系的2个群体聚为一枝, 其余水系群体聚为另一枝。贝叶斯分析也支持这一结果, 将6个鲫群体划分为2个最佳理论群。利用8个EST-SSR标记在6个鲫群体中共检测到155个等位基因, 平均N_a、N_e、H_o、H_e以及PIC分别为19、9.5、0.728、0.870和0.855; 群体间F_st值和Nei’s遗传距离分别介于0.005—0.084和0.117—0.683; 基于EST-SSR标记的UPGMA聚类分析和贝叶斯分析也将6个鲫群体划为两大类群: 黑龙江水系群体; 长江、奉化江和淮河水系群体。G-SSR和EST-SSR标记检测6个鲫群体的平均多态信息含量(PIC)分别为0.786—0.864和0.761—0.833。研究结果显示: 6个野生鲫群体均具有较高的遗传多样性, 但黑龙江水系群体多样性低于其他水系群体; 尽管EST-SSR标记的多态性略小于G-SSR标记, 但是2类微卫星标记均揭示了相似的鲫群体遗传结构和分化格局。研究结果对鲫种质资源的保护和EST-SSR标记在鱼类群体遗传学研究价值的评价提供了新的信息。     

Pattern of genetic variation of yellow catfish Pelteobagrus fulvidraco Richardso in Huaihe river and the Yangtze river revealed using mitochondrial DNA control region sequences

Genetic variability and population genetic structure of the yellow catfish Pelteobagrus fulvidraco Richardso in the Huaihe river and the Yangtze river was examined with a 810-bp of the mitochondrial DNA control region. A total of 70 haplotypes were identified from 145 samples, which were characterized with high haplotype diversity (h = 0.9832 ± 0.0041) but low nucleotide diversity (π = 0.0415 ± 0.0201). The analysis of molecular variance and phylogenetic reconstructions detected significant geographic structure between Huaihe river and Yangtze with F_ST = 0.1183 (P = 0.0000). Neighbor-joining (NJ) phylogenetic analyses identified two distinct clades (bootstrap support 99 %). The medium joining network drawn using the complete data set was reticulated and also distinctly split the 70 haplotypes into two groups corresponding to those of the NJ tree. Departures from neutrality were not significant for the Huaihe river and the Yangtze river Pelteobagrus fulvidraco, concordant with the observed multimodal mismatch distributions (P > 0.05), which suggested that the effective size of this species has been large and stable for a long period. The question about the existence of significant genetic differentiation for Pelteobagrus fulvidraco in the Yangtze river and Huaihe river basins remains to be further studied with molecular nuclear markers and larger sample sizes from throughout the river basins.     

中国大鲵四种群的遗传结构和地理分化

为了确定栖息地的破碎化和片断化引起中国大鲵的地理分化和遗传结构变异,本文测定了来自广西、河南、陕西和湖南4个地理种群的28条大鲵的mtDNAD loop基因全序列。根据这4个地理种群的地理分布,分成珠江单元(广西种群)、黄河单元(河南种群)和长江单元(湖南和陕西种群)。通过ClustalX、MEGA2.0、DnaSP4.0、Arlequin1.1分析发现,全序列长度为771bp,其中64个多态性核苷酸变异位点,占全部碱基数的8.26%。转换和颠换分别为6和2个,插入/缺失11个。27个单倍型间的序列差异平均为1.32%。3个单元的单倍型多样性指数和核苷酸多样性指数值都偏低,而且珠江单元的这两个指数值都低于长江和黄河两个单元。珠江单元和黄河、长江单元之间分化程度显著(P<0.001),而长江和黄河单元之间差异不显著(P>0.05)。地理单元内分化程度占99.31%,而单元间只有0.69%,表明遗传差异主要发生在单元内,而且各地理单元之间的基因流较频繁。构建的NJ树和MP树显示,27个单倍型呈现一种混杂的分布格局,并未分成代表3个地理单元的聚合群。     

长江中上游银[鱼句]线粒体DNA遗传多样性分析

银[鱼句]（Squalidus argentatus）是长江常见小型鱼类,分布广泛于干支流,资源量较大。本研究采用线粒体DNA（mtDNA）细胞色素b基因序列对长江中上游干流江津、荆州、监利、洪湖、黄石江段及支流赤水河、湘江等7个江段共217尾银[鱼句]样品的遗传结构和遗传多样性进行了分析。结果显示,银[鱼句]群体Cyt b基因序列分别检出了81个变异位点和97个单倍型,平均单倍型多样性（Hd）和核苷酸多样性（Pi）分别为0.966和0.008 6。分子方差分析（AMOVA）显示,长江中上游银[鱼句]群体存在显著遗传分化。群体间两两比较分析发现,赤水河群体与其他群体基因交流程度低,遗传分化显著,其他群体间没有显著遗传分化。中性检验结果不支持银 历史上发生过群体扩张。     

浅水湖泊鱼类群落结构评估: 复合网目刺网与网簖的比较

准确评估鱼类群落结构是渔业管理和鱼类资源养护的必要前提, 而不同渔具采样结果往往会产生较大差异。研究同时采用欧洲标准采样网具-复合网目刺网(Multi-mesh gillnet)和中国传统网具-网簖对长江中游典型浅水湖泊扁担塘的鱼类群落结构进行了评估。2种网具共采集到27种鱼类, 并发现黄尾鲴(Xenocypris daviai)和湖鲚(Coilia nasus taihuensis)2种新记录种, 扁担塘的鱼类群落结构较1999年和2003年均发生了较明显的改变。2种渔具捕获的鱼类组成、相对丰度和生物量以及鱼类体长分布频率均存在显著性差异。基于鱼类的相对生物量和相对丰度的NMDS排序表明2种网具捕获到的鱼类群落结构也存在显著差异。另外还比较了复合网目刺网与其他定量采样网具间的差异, 作者认为复合网目刺网比较适合长江中下游浅水湖泊鱼类群落研究的定量取样, 但仅凭单一网具评估鱼类群落结构具有局限性。     

Genetic differentiation of Macrognathus siamensis within the Mekong River between Laos and Cambodia

This study investigated the genetic variation in the Mastacembelidae fish Macrognathus siamensis by sequencing 1047 bp of the mitochondrial ND2 gene of 48 fish samples collected in the Mekong River. They were divided into 15 mtDNA haplotypes. The haplotype network and Bayesian tree revealed striking genetic differences between the Laos and Cambodian samples. The high pairwise F statistic values (0.93–0.97) also confirmed this genetic differentiation. Analysis of the molecular clock indicated that these two samples separated approximately four million years ago. Most likely, the genetic variation was influenced by immigration and isolation events as well as by environmental factors. Furthermore, the present study results could be valuable in identifying the conservation and resource management units of this species.     

Genetic diversity in population of largemouth bronze gudgeon (Coreius guichenoti Sauvage et Dabry) from Yangtze River determined by microsatellite DNA analysis

Largemouth bronze gudgeon (Coreius guichenoti Sauvage et Dabry 1874), one of the endemic fish species in the upper reaches of the Yangtze River in China, is a benthic and potamodromous fish that is typically found in rivers with torrential flow. Three dams in the Yangtze River, Ertan Dam, Three Gorges Dam and Gezhouba Dam, may have had vital impacts on the habitat and spawning behaviors of largemouth bronze gudgeon, and could ultimately threaten the survival of this fish. We studied the population genetic diversity of C. guichenoti samples collected at seven sites (JH, GLP, BX, HJ, MD, SDP and XB) within the Yangtze River and one of its tributaries, the Yalong River. Genetic diversity patterns were determined by analyzing genetic data from 11 polymorphic microsatellite loci. A high genetic diversity among these largemouth bronze gudgeon populations was indicated by the number of microsatellite alleles (A) and the expected heterozygosity (HE). No significant population variation occurred among GLP, BX, HJ and MD populations, but dramatic population differentiation was observed among JH and XB, two dam-blocked populations, versus other populations. Tests for bottlenecks did not indicate recent dramatic population declines and concurrent losses of genetic diversity in any largemouth bronze gudgeon populations. To the contrary, we found that dams accelerated the population differentiation of this fish.     

两种(鱼尝)科鱼类在长江和珠江流域Cytb基因序列变异性分析

采用PCR技术获得了长江和珠江流域的两种鲿科鱼类1137bp Cytb基因的片段,进行了序列测定,并用Mega软件进行了序列分析。研究发现两种鲿科鱼类的全序列从第十位碱基起有一个三联体密码子的缺失,推测为鲇形目鱼类Cytb序列所特有特征。黄颡鱼和大鳍鳠种群间的序列差异分别为0．4％和1．6％,介于一般淡水鱼类mtDNA种内序列的变异范围,而高于洄游鱼类序列变异。黄颡鱼属和鲮属Cytb基因序列间的差异为17．6％-18．0％,大大高于种间的序列差异率,也从分子水平上证实了二者属级分类单元的有效性。依据分子进化速率推测,长江和珠江两水系间大鳍鳠的分歧时间为距今27万年左右的更新世中晚期,黄颡鱼的分歧时间在距今7万年左右的更新世末期。推测造成二者有着不同分歧时间的可能原因是：大鳍鳠属暖水性鱼类,在第四纪冰川期间,由于全球性气候变冷,大鳍鳠退至长江以南,并在各水系间产生隔离,各自独立分化至今。而黄颡鱼具有很强的适应性,在第四纪数次冰川期间可能进行过广泛的交流。     

Low variation but strong population structure in mitochondrial control region of the plains topminnow, Fundulus sciadicus

The plains topminnow Fundulus sciadicus is a freshwater killifish endemic to the Great Plains of North America. Rising concerns for future viability of this species have prompted recent changes in its conservation status. In this study, the results of a range-wide population genetic survey based on the sequence of entire mitochondrial control region (CR) are presented. A total of 181 fish were collected from 11 sites in Nebraska and 10 sites in Missouri spanning the distribution range of the species. Seven polymorphic sites were found in the 966 base pairs of the CR, and only nine unique haplotypes were detected among all fish. Phylogenetic analysis and statistical parsimony networks identified two distinct clades. The first included fish in the Osage, Gasconade and Spring River drainages in Missouri, while the second included individuals from Nebraska and the Lamine River in Missouri, although the Lamine River is much closer to the other Missouri sites than to the Nebraska sites. Pair-wise F _ST and average population distances indicated that populations from most drainages are genetically distinct, as 93% of the total molecular variance was attributed to among-drainage effects. Four sites within the main distributions of this species and a highly disjunct site from the south-western portion of the range are suggested as potential targets for conservation.     

Genomic evidence for the population genetic differentiation of Misgurnus anguillicaudatus in the Yangtze River basin of China

Misgurnus anguillicaudatus, an important aquatic species, is mainly distributed in the Yangtze River basin. To reveal the population genetic structure of M. anguillicaudatus distributed in the Yangtze River basin, genotyping by sequencing (GBS) technique was employed to detect the genome wide genetic variations of M. anguillicaudatus. A total of 30.03 Gb raw data were yielded from 70 samples collected from 15 geographic sites located in the Yangtze River basin. Subsequently, 2092 high quality SNPs were genotyped across these samples and used for a series of genetic analysis. The results of genetic analysis showed that high levels of genetic diversity were observed and the populations from upper reaches (UR) were significantly differentiated from the middle and lower reaches (MLR) of Yangtze River basin. Meanwhile, no significant isolation by distance was detected among the populations. Ecological factors (e.g. complicated topography and climatic environment) and anthropogenic factors (e.g. aquaculture and agriculture cultivation) might account for the genetic disconnectivity between UR and MLR populations. This study provided valuable genetic data for the future breeding program and also for the conversation and scientific utilization of those abundant genetic resources stored in the Yangtze River basin.