Montagem de cariótipo de peixes assistida por computador

Abstract

Fish karyotyping plays an important role in studies of cytotaxonomy and chromosomic evolution of species. However, few semi or completely automated fish karyotyping systems are available. This work proposes and evaluates an image-based tool to assist fish karyotyping. The analyzed species were Hoplias malabaricus (Bloch, 1794), Hypostomus ancistroides (Ihering, 1911), and Parauchenipterus galeatus (Linnaeus, 1766). In Portuguese, these species are commonly refered to as traíra, cascudo and bagre sapo, respectively. A total of 100 metaphases were analyzed by two methods: (1) semi-automatic karyotype generation and (2) automatic karyotype generation. The results were analyzed using Pearson correlation, difference graphs and counting tables. The reference used for the evaluation of the system was the average of the counts made by four experts. In method 1, four users performed counts on the 100 metaphases with interobserver correlation of r ≥ 0.997. The total number of chromosomes identified by method 1 was 4348 and method 2 was 4135, excluding 1,3% false positives, resulting in an automatic identification of approximately 95,1% of the chromosomes present in the images. False negatives represent 4,9% of the total chromossomes. The correlation between the methods was r = 0.93. The results indicate that the tool can be introduced for fish karyotyping procedures contributing for accelerating the process with acceptable accuracy.