Tracing the evolution of fatty acid-binding proteins (FABPs) in organisms with a heterogeneous fat distribution

The distribution of fat among both invertebrate and vertebrate groups is heterogeneous. Studies have shown that fatty acid-binding proteins (FABPs), which mainly bind and transport fatty acids, play important roles in the regulation of fat storage and distribution. However, the systematic and genome-wide investigation of FABP genes in organisms with a heterogeneous fat distribution remains in its infancy. The availability of the complete genomes of Caenorhabditis elegans, Callorhinchus milii, and other organisms with a heterogeneous fat distribution allowed us to systematically investigate the gene structure and phylogeny of FABP genes across a wide range of phyla. In this study, we analyzed the number, structure, chromosomal location, and phylogeny of FABP genes in 18 organisms from C. elegans to Homo sapiens. A total of 12 types of FABP genes were identified in the 18 species, and no single organism exhibited all 12 fatty acid-binding genes (FABPs). The absence of a specific FABP gene in tissue may be related to the absence of fat storage in the corresponding tissue. The genomic loci of the FABP genes were diverse, and their gene structures varied. The results of the phylogenetic analysis and the observation of conserved gene synthesis of FABP family genes/proteins suggest that all FABP genes may have evolved from a common ancestor through tandem duplication. This study not only lays a strong theoretical foundation for the study of fat deposition in different organisms, but also provides a new perspective regarding metabolic disease prevention and control and the improvement of agricultural product quality.