Contração e expansão de famílias de proteína de choque térmico e a adaptação ambiental em moluscos

Abstract

The molluscs are unique for the variety of bauplans and for the breadth of colonized habitats. Such ability to adapt to different environments seems to facilitate the occurrence of invasive species among the phylum, which negatively impact environments worldwide. However, the genetic origins of this diversity are little explored – in fact, this lack of representation extends to other invertebrates, despite the fact that they comprise 95% of the animal diversity. Thus, this study proposes the utilization of bioinformatics methods to reduce this knowledge gap and to investigate the adaptability of molluscs. Therefore, the dynamics of one of the main protein families linked to the stress response was investigated – the heat shock proteins (HSP). Since they are related to the response to different stressors, the expansion of their families may imply an increase in tolerance to multiple environments.. Thus, genomic assemblies of molluscs available in the NCBI were obtained, as well as their HSPs sequences. To identify these protein coding sequences in assemblies that were not annotated, a reference genome was selected. In addition to the abundance of protein coding portions in the genomes, the formation of clusters between them were investigated, allowing to infer their families and expansion patterns. A direct relationship between the proportion of HSPs and the environmental adaptability of molluscs was not identified. However, 1,586 new possible HSP sequences were predicted and an expansion of HSP70 in the phylum was verified. In addition to this family, smaller clusters of HSP10, HSP60 and HSP90 were also detected. In bivalves, the expansion is more expressive, mainly in the families Ostreidae and Pectinidae. Such findings encourage the need for further studies to ascertain the abiotic adaptability of molluscs.