摘要
报道了西藏鱼类染色体多样性的研究结果。黑斑原■的染色体数目2n=48,核型公式为20m+12sm+10st+6t;同时还存在2n=42与2n=44两种类型,并据此认为黑斑原■不应是■科鱼类中的最特化种。西藏高原鳅、尖裸鲤、拉萨裸裂尻鱼、异齿裂腹鱼和拉萨裂腹鱼的染色体数目与核型公式分别为2n=50=14m+4sm+22st+10t,2n=86=24m+12sm+22st+18t,2n=94=22m+8sm+46st+18t,2n=106=24m+26sm+30st+26t,2n=112=26m+24sm+28st+34t,在数目和核型或图像上有别于前人的报道。首次报道小眼高原鳅、高原裸鲤的染色体数目、核型及巨须裂腹鱼的核型公式,依次为2n=50=16m+12sm+12st+10t,2n=94=24m+14sm+22sm+34t,2n=102=20m+28sm+22st+16t。佩枯湖裸鲤的染色体数目2n=66,是裂腹鱼类中最少的。双须叶须鱼染色体的数目则极多,2n=424～432,甚为罕见,两者都有待进一步研究。西藏鱼类的染色体多样性十分丰富,表现出裂腹鱼类、鳅科和■科鱼类各属、种之间的差别以及种内不同居群甚至同一个体的细胞之间的差异。该特点可能与鱼类物种形成所处的不稳定环境有关。在探讨鱼类分类地位和演化关系时,染色体组型有一定的可信度,但只有当一个类群或属或种的染色体组型完全稳定时才可作为依据予以采用。
This article reports chromosome diversity of 12 species of Tibetan fishes.The results of our experiment are as follows:①Chromosome number and karyotype formula of Glyptosternum maculatum are 2n=48=20?m+12?sm+10?st+6?t,with other two kinds of 2n=44 and 2n=42,which doubt the Ren's conclusion that it was the most advanced species in Sisorid fishes.②Chromosome number and karyotype formulae of Triplophysa tibetana,Oxygymnocypris stewartii,Schizopygopsis younghusbandii,Schizothorax (Racoma) o'connor and Schizothorax (Racoma) waltoni are 2n=50=14?m+4?sm+22?st+10?t,2n=86=24?m+12?sm+22?st+18?t,2n=94=22?m+8?sm+46?st+18?t,2n=106=24?m+26?sm+30?st+26?t,2n=112=26?m+24?sm+28?st+34?t,respectively,which differ from former conclusions.③In this article,chromosome number,karyotype formulas and orignal pictures of Triplophysa microps and Gymnocypris waddelli ,and karyotype formula,original picture of Schizothorax ( R ) macropogon are firstly reported as 2n=50=16?m+12?sm+12?st+10?t,2n=94=24?m+14?sm+22?st+34?t,2n=102=20?m+28?sm+22?st+16?t,respectively.④Chromosome number of Gymnocypris dobula is 2n=66,the least in Schizotho racin fishes,while that of Ptychobarbus dipogon is 2n=424～432,mostly rare in Vertebrata,which need further research. Lastly,the authors consider chromosome diversity among each species and genus in three groups (Schizothoracines,Cobitids and Sisorids) of Xizang (Tibet) fishes is abundant,showing not only obvious difference among species,genus and groups,but variation in one species,even in individual.It is supposed that this is concerned with the unstable surrounding during speciation.For a certain confidence in chromosome variation,only stable karyotype can be used as proof in taxonomy and evolution.
基金
珠峰自然保护区国家基金!( 2 40 92 0 13 0 )
关键词
染色体多样性
染色体数目
西藏鱼类
分类
演化
Chromosome diversity,Chromosome number,Karyotype formula,Tibetan fishes,Taxonomy and evolution
