Unraveling the role of salt-sensitivity genes in obesity with integrated network biology and co-expression analysis.

Obesity is a multifactorial disease caused by complex interactions between genes and dietary factors. Salt-rich diet is related to the development and progression of several chronic diseases including obesity. However, the molecular basis of how salt sensitivity genes (SSG) contribute to adiposity in obesity patients remains unexplored. In this study, we used the microarray expression data of visceral adipose tissue samples and constructed a complex protein-interaction network of salt sensitivity genes and their co-expressed genes to trace the molecular pathways connected to obesity. The Salt Sensitivity Protein Interaction Network (SSPIN) of 2691 differentially expressed genes and their 15474 interactions has shown that adipose tissues are enriched with the expression of 23 SSGs, 16 hubs and 84 bottlenecks (p = 2.52 x 10-16) involved in diverse molecular pathways connected to adiposity. Fifteen of these 23 SSGs along with 8 other SSGs showed a co-expression with enriched obesity-related genes (r ≥ 0.8). These SSGs and their co-expression partners are involved in diverse metabolic pathways including adipogenesis, adipocytokine signaling pathway, renin-angiotensin system, etc. This study concludes that SSGs could act as molecular signatures for tracing the basis of adipogenesis among obese patients. Integrated network centered methods may accelerate the identification of new molecular targets from the complex obesity genomics data.

SNP mapping and phylogenetic analysis of Saudi Arabian horse breeds based on mitochondrial genome sequencing

Arabian horse breeds (Equus caballus L.) are renowned for elegance, endurance and their contribution to Thoroughbreds. In heredity, the mitochondrial (mt) genome is maternally inherited and represents extensive genetic diversity. The mt genomes of Seglawi and Hadban horse breeds of Saudi Arabia were sequenced to decipher the genetic variations in the coding and non-coding regions. We observed that the coding region of mt genome has 11 and 34 amino acid variations in Seglawi and Hadban breeds, respectively. Sequencing analyses of COX1 gene indicated highest variations of which, 5 in Seglawi and 8 in Hadban followed by the NADH5 gene. The mitochondrial genes of respiratory chain showed positive selections with respect to different environments. Our data also highlighted that the Hadban breed had much higher nucleotide changes as compared to Seglawi and together they formed individual branches in phylogenetic tree. However, the tree shows that they were relatively branched to Arabian horse breeds. This study on two Arabian horses shed light on variations among mt genes and their phylogenetic relationship with other horse breeds.