South American Cichlid Fishes Comparative Genomics Using Large Scale Approach

Large scale analysis approach brings new insights to integration of cytogenetic and genomic data, leading to understand structural organization and evolution of genomes. Cichlid fishes experienced rapid and extensive adaptive radiation process, becoming a great model to evolutionary studies. African cichlids show a genomic organization conserved pattern in genomic and cytogenetic studies. In the other hand, only cytogenetic approaches have been applied to the South American cichlids. The current scenario to this group indicates that they present a greater variance than the African group, although they belong to the same family. Therefore, this project aims to relate cytogenetic and genomic data of South American cichlids, contributing to better understand its evolutionary history. Our hypothesis is that the genomic organization of this group presents more variation in sequences arrangement than the African cichlid group, based on its karyotype variation. We have sequenced, assembled, annotated and compared four South American cichlid species.  In S. discus, we verified different patterns during the assembly process and, also, during SNPs count related to sex libraries. Furthermore, C. vazzoleri, presented low substitution levels in repetitive sequences, indicating great amount of repetitive DNA recently inserted in the genome. In the other hand, all results obtained lead to a conserved pattern of genomic sequences (abundance and genomic proportion) among the South American species. In conclusion, our results refute the initial hypothesis, but they are just preliminary and further analysis such as multiple genome alignment must be performed to corroborate this idea.