Impacts of Stress Caused by Copper Sulfate (CuSO4) on the Genome of the Tambaqui (Colossoma macropomum): Quantification of Rex1 and Heterochromatic Profile

: The transposable elements are known by their ability to move and integrate into the genome of the host organism. They are classified in retrotransposons class I, which has, as intermediate of the transposition, the RNA and retrotransposons class II, which is composed of the DNA transposons, whose DNA migrates directly or is copied and inserted into the genome. The retrotransposable element Rex 1 is a non-LTR retrotransposon found in several types of organisms. Many studies indicate that the Rex retrotransposons have the capacity to respond to environmental stress. The results found in this study corroborate the hypothesis that this retrotransposon possesses a response to environmental stress, since the chromosomal mapping, obtained through FISH, showed a higher number of markings on animals that were submitted to stress in 48h by the copper sulfate action. Furthermore, we can identify an increase in heterochromatic regions in the chromosomes. In the absolute quantification by Real-Time PCR, we found the largest numbers of Rex 1 copies in the samples that were submitted to environmental stress by copper sulfate.