10 research outputs found
ââWhy me, why now?â Using clinical immunology and epidemiology to explain who gets nontuberculous mycobacterial infection
Cancer of the prostate presenting with diffuse osteolytic metastatic bone lesions: a case report
Effect of Pagetâs disease of bone (osteitis deformans) on the progression of prostate cancer bone metastasis
Quantitative Genetic Analyses of Male Color Pattern and Female Mate Choice in a Pair of Cichlid Fishes of Lake Malawi, East Africa
Yeasts, enteric rods and pseudomonads in the subgingival flora of severe adult periodontitis
Multiple trans QTL and one cis-regulatory deletion are associated with the differential expression of cone opsins in African cichlids
Abstract Background Dissecting the genetic basis of phenotypic diversity is one of the fundamental goals in evolutionary biology. Despite growing evidence for gene expression divergence being responsible for the evolution of complex traits, knowledge about the proximate genetic causes underlying these traits is still limited. African cichlids have diverse visual systems, with different species expressing different combinations of seven cone opsin genes. Using opsin expression variation in African cichlids as a model for gene expression evolution, this study aims to investigate the genetic architecture of opsin expression divergence in this group. Results Results from a genome-wide linkage mapping on the F2 progeny of an intergeneric cross, between two species with differential opsin expression show that opsins in Lake Malawi cichlids are controlled by multiple quantitative trait loci (QTLs). Most of these QTLs are located in trans to the opsins except for one cis-QTL for SWS1 on LG17. A closer look at this major QTL revealed the presence of a 691âbp deletion in the promoter of the SWS1 opsin (located 751âbp upstream of the start site) that is associated with a decrease in its expression. Phylogenetic footprinting indicates that the region spanning the deletion harbors a microRNA miR-729 and a conserved non-coding element (CNE) that also occurs in zebrafish and other teleosts. This suggests that the deletion might contain ancestrally preserved regulators that have been tuned for SWS1 gene expression in Lake Malawi. While this deletion is not common, it does occur in several other species within the lake. Conclusions Differential expression of cichlid opsins is associated with multiple overlapping QTL, with all but one in trans to the opsins they regulate. The one cis-acting factor is a deletion in the promoter of the SWS1 opsin, suggesting that ancestral polymorphic deletions may contribute to cichlidâs visual diversity. In addition to expanding our understanding of the molecular landscape of opsin expression in African cichlids, this study sheds light on the molecular mechanisms underlying phenotypic variation in natural populations