The evolutionary dynamics of repeat sequences is quite complex, with some duplicates never having differentiated from each other. Two models can explain the complex evolutionary process for repeated genes---concerted and birth-and-death, of which the latter is driven by duplications maintained by selection. Copy number variations caused by random duplications and losses in repeat regions may modulate molecular pathways and therefore affect phenotypic characteristics in a population, resulting in individuals that are able to adapt to new environments. In this study, we investigated the filaggrin gene (FLG), which codes for filaggrin---an important component of the outer layers of mammalian skin---and contains tandem repeats that exhibit copy number variation between and within species. To examine which model best fits the evolutionary pathway for the complete tandem repeats within a single exon of FLG, we determined the repeat sequences in crab-eating macaque (Macaca fascicularis), orangutan (Pongo abelii), gorilla (Gorilla gorilla), and chimpanzee (Pan troglodytes) and compared these with the sequence in human (Homo sapiens).
Journal: BMC evolutionary biology