Chromosome karyotyping is the main content in cytogenetic study. Manual analysis, image systemic analysis and software analysis are the most commonly used methods in chromosome karyotyping. But all three methods have their own disadvantage, which are large measurement error, high quality metaphase image require-ment and uncontrollable detail error, respectively. In order to obtain accurate and convenient chromosome karyo-type analysis method,the introduced salt-tolerant varieties,Barbus capito,was used as experimental fish.The metaphase chromosomes of B.capito were obtained from head kidney tissue by the method of PHA and col-chicine injection and then the chromosome samples were prepared by air-drying technique. We presented a meth-od for chromosome karyotyping by combining two software E-ruler and Photoshop, and compared the measure and karyotyping results from the regular method. The results showed that there is no significant difference in the measurement of stretched straight chromosomes by E-ruler software and conventional methods, however, the former is more accurate in the measurement of curved chromosome. Photoshop software can quickly and conveni-ently complete the chromosome, because it can accurately judge the location of centromere by eliminating the background of karyotype. It can be concluded that E-ruler and Photoshop combining method achieved much more accurate and clear karyotyping results. As an accurate and convenient method, this new method can also be used in chromosome analysis of other fish species and even other organisms. The results showed that the chromosome ploidy of B.capito was diploid,and no gender-related heterotypical chromosomes were found.The karyotype for-mula was:2n=100=12m+38sm+38st+12t,NF=150.Compared with other species from Barbinae family,B.capito has similar karyotypes to several domestic species, which shows the karyotype evolutionary characters.%染色体核型分析是细胞遗传学研究的主要内容.为了获得准确、便捷的染色体核型分析方法,以引进耐盐碱品种大鳞鲃为实验材料,取头肾细胞冷滴片法制备染色体标本,采用E-ruler测量软件和Photoshop图像软件结合完成了染色体核型分析,并与常规方法的测量结果、核型分析进行了比较.结果显示,E-ruler软件与常规方法对伸展平直染色体的测量无显著差异,前者对弯曲形态染色体的测量结果更为准确;Photoshop图像软件能剔除染色体中期分裂相照片的背景,准确判断着丝粒的位置,快速、便捷地完成染色体核型图拼贴.研究表明,利用E-ruler软件和Photoshop软件相结合可获得准确、清晰的核型分析结果,本方法适用于其他鱼类和生物的染色体核型分析.染色体分析结果显示,大鳞鲃的染色体组为二倍体,未发现与性别有关的异型染色体,核型公式为2n=100=12m+38sm+38st+12t,NF=150.同鲃科其他鱼类的核型相比,大鳞鲃与国内几种倒刺鲃核型类似,具有鲃亚科进化核型特征.
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