【作者】 孙玉苗；

【导师】 祝茜； 刘焕章；

【作者基本信息】 山东大学 ， 动物学， 2008， 硕士

【摘要】 吻鮈属(Rhinogobio)隶属于鲤形目(Cypriniformes)鲤科(Cyprinidae)鮈亚科(Gobioninae),为中国的特有属;包括有吻鮈(R.typus Bleeker)、圆筒吻鮈(R.cylindricus Günther)、长鳍吻鮈(R.ventralis Sauvage et Darbry)、湖南吻鮈(R.hunanensis Tang)和大鼻吻鮈(R.nasutus(Kessler))5个有效种。本研究以吻鮈、圆筒吻鮈和长鳍吻鮈为对象,探究吻鮈属鱼类物种分化的问题。研究得到的主要结果如下。1.采用分子系统学的方法,以线粒体细胞色素b基因序列和S7核糖体蛋白基因内含子1序列为分子标记,研究吻鮈属鱼类分子系统发育、物种分化过程及动态历史:ⅰ本研究共获得了81尾吻鮈、72尾圆筒吻鮈和107尾长鳍吻鮈的线粒体细胞色素b基因序列,以及10尾吻鮈、14尾圆筒吻鮈和12尾长鳍吻鮈的S7核糖体蛋白基因内含子1序列;发现两尾圆筒吻鮈同吻鮈的线粒体细胞色素b基因序列具有共享单倍型,推测这两尾圆筒吻鮈可能为吻鮈和圆筒吻鮈渐渗杂交的后代。ⅱ以鮈亚科的麦穗鱼(Pseudorasbora parva)和铜鱼(Coreius heterodon)为外类群,基于线粒体细胞色素b基因序列构建的NJ树(Neighbor-joining tree)中,吻鮈和圆筒吻鮈构成姐妹群关系,再和位于系统发育树的基部的长鳍吻鮈聚在一起。以铜鱼为外类群,基于S7核糖体蛋白基因内含子1序列构建的NJ树得出同样的结果。这表明在吻鮈、圆筒吻鮈和长鳍吻鮈三物种间,圆筒吻鮈和吻鮈具有更近的亲缘关系,长鳍吻鮈是三物种中较原始的物种。ⅲ长鳍吻鮈同圆筒吻鮈和吻鮈的共同祖先在大约6.19百万年前的中新世末期发生分歧;和吻鮈、圆筒吻鮈已形成完善的繁殖隔离。ⅳ吻鮈和圆筒吻鮈的分歧发生在约2.285百万年前的上新世末期。推测目前吻鮈和圆筒吻鮈已经毫无疑问地成为“好种”,但还存在一定程度的渐渗杂交。二物种的渐渗杂交是吻鮈基因库中的基因向圆筒吻鮈基因库发生了渗漏。ⅴ吻鮈、圆筒吻鮈和长鳍吻鮈分别在大约87084世代、42304世代和48560世代前经历过种群扩张。2.对65尾吻鮈、42尾圆筒吻鮈和72尾长鳍吻鮈的13个计数性状和24个比例性状作了主成分分析和聚类分析,并对部分性状作簇状条形图,以探讨吻鮈属鱼类形态差异及特征演化:ⅰ本研究理清了吻鮈、圆筒吻鮈和长鳍吻鮈的性状差异。侧线上鳞、侧线下鳞和背鳍长/头长是区分长鳍吻鮈同吻鮈、圆筒吻鮈的最有效性状。尾柄高/体长以及眼径/体长是区分吻鮈同圆筒吻鮈的最有效性状。长鳍吻鮈的侧线上鳞数目在7.0—8.5之间,平均7.25±0.40;圆筒吻鮈的侧线上鳞数目在6.0—7.0之间,平均6.03±0.16;吻鮈的侧线上鳞数目在6.0—7.0之间,平均6.02±0.14。长鳍吻鮈的侧线下鳞数目在6.0—8.0之间,平均6.72±0.48;圆筒吻鮈的侧线下鳞数目在5.0—6.0之间,平均5.26±0.30;吻鮈的侧线下鳞数目在4.0—5.5之间,平均4.68±0.39。长鳍吻鮈的背鳍长/头长均大于1,而吻鮈和圆筒吻鮈的背鳍长均小于头长。吻鮈的尾柄高/体长的范围在0.065—0.080之间,平均0.071±0.003;而圆筒吻鮈的尾柄高/体长在0.081—0.096之间,平均0.087±0.003。吻鮈的眼径/体长在0.039—0.056之间,平均0.046±0.003;而圆筒吻鮈的眼径/体长在0.026—0.035之间,平均0.031±0.002。ⅱ吻鮈属鱼类有如下的形态演化趋势:侧线鳞数目增多;侧线上鳞、侧线下鳞、背鳍前鳞和胸鳍分支鳍条数目减少;身体渐趋于圆柱状;尾柄高和体高渐变窄;眼睛渐变大;吻渐变长;背鳍、胸鳍、腹鳍和臀鳍渐变短;背鳍基和臀鳍基渐变窄;肛门位置渐前移。ⅲ吻鮈、圆筒吻鮈和长鳍吻鮈的形态分化是对环境适应进化的结果。长鳍吻鮈更为强大的鳍、更强壮的尾柄和较小的眼径及较短的吻部是其对急流生活的适应。而吻鮈和圆筒吻鮈的形态特征适应于流速较缓而清澈的河道。ⅳ形态分析支持遗传分析得出的关于三物种物种分化的结果。更多还原

【Abstract】 Rhinogobio,an endemic genus to China,belongs to Gobioninae,Cyprinidae, Cypriniformes;which consists of 5 species:R.typus Bleeker,R.cylindricus Günther, R.ventralis Sauvage et Darbry,R.hunanensis Tang and R.nasutus(Kessler).By using 3 species R.typus Bleeker,R.cylindricus Günther and R.ventralis Sauvage et Darbry as the subjects,the persent study aims to investigate speciation of this genus. The followings are the main conclusions.1.The study investigates phylogeny,speciation and population history of species in Rhinogobio by using Cyt b gene and intron I of S7 ribosomal protein gene as the molecular markers:ⅰ260 Cyt b gene sequences(81 from R.typus,72 from R.cylindricus and 107 from R.ventralis)and 36 sequences of intron I of S7 ribosomal protein gene(10 from R.typus,14 from R.cylindricus and 12 from R.ventralis)were obtained.Two samples of R.cylindricus share common haplotyes of Cyt b gene with R.typus.It is suggested that the two samples of R.cylindricus should be the offsprings of R.typus and R.cylindricus as the result of introgressive hybridization.ⅱThe phylogenetic relationship is constructed using neighbor-joining method based on Cyt b gene and intron I of S7 ribosomal protein gene.R.typus and R. cylindricus are more closely related to each other than to R.ventralis.R.ventralis is more distal-related to the other two species.ⅲR.ventralis and the ancestor of R.typus and R.cylindricus differentiated in late Miocene about 6.19 million years ago,and have become perfectly reproductively isolated from R.typus and R.cylindricus.ⅳR.typus and R.cylindricus differentiated in late Pliocene about 2.285 million years ago.R.typus and R.cylindricus are definitely ’good species’ at present,but they still introgressively hybridized to some degree.Their introgressive hybridization consists of the leakage of the alleles from R.typus gene pool to R.cylindricus.ⅴR.typus,R.cylindricus and R.ventralis experienced population expansion about 87084,42304 and 48560 generations ago respectively.2.Thirteen meristic characters and 24 measurable characteristics of 179 samples (65 from R.typus,42 from R.cylindricus and 72 from R.ventralis)were analyzed to investigate the morphological differences and character evolution of species in Rhinogobio,using the methods of principal component analysis,cluster analysis and making clustered bar charts:ⅰThe morphological differences among R.typus,R.cylindricus and R.ventralis are specified perspicuously.The most distinguishable characters of R.ventralis are the number of scales above the lateral line,scales below the lateral line and the ratio of dorsal fin length to head length.The ratio of caudal depth to body length and the ratio of eye diameter to body length are the most effective characters to distinguish R.typus and R.cylindricus.The number of scales above the lateral line ranges from 7.0 to 8.5 with an average of 7.25±0.40 in R.ventralis;The number of scales above the lateral line in R.typus and R.cylindricus both ranges from 6.0 to 7.0 with an average of 6.03±0.16 and 6.03±0.16 respectively.The number of scales below the lateral line ranges from 6.0 to 8.0 with an average of 6.42±0.48 in R.ventralis;the number of scales below the lateral line ranges from 5.0 to 6.0 with an average of 5.26±0.30 in R. cylindricus;and in R.typus,the number of scales below the lateral line ranges from 4.0 to 5.5 with an average of 4.68±0.39.The ratio of dorsal fin length to head length is above 1 in R.ventralis;but in R.typus and R.cylindricus,the ratio is below 1.The ratio of caudal depth to body length in R.typus ranges from 0.065 to 0.080 with an average of 0.071±0.003;but in R.cylindricus,the ratio ranges from 0.081 to 0.096 with an average of 0.087±0.003.The ratio of eye diameter to body length in R.typus ranges from 0.039 to 0.056 with an average of 0.046±0.003;but in R.cylindricus,the ratio ranges from 0.026 to 0.035 with an average of 0.031±0.002.ⅱThere is an evolutionary trend in the genus Rhinogobio towards more lateral line scales,less scales above and below the lateral line,less predorsal scales,less ramose pectoral fin rays,a more columned body figure,a lower body and caudal depth,larger eyes,a longer snout,shorter fins,narrower dorsal and anal fin base length and a more anterior anus. ⅲThe differentiation of morphological characters is the result of adaption evolution.R.ventralis with stronger caudal peduncal and fins,smaller eyes and a shorter snout is adapted to fast-flowing tuibid rivers and R.typus and R.cylindricus are adapted to slow-flowing clear habitats.ⅳThe morphological results support the conclusions of molecular analysis about the speciation of the genus Rhinogobio.更多还原