Duplication and sub/neofunctionalization of Malvolio, an insect homolog of Nramp, in the subsocial beetle Nicrophorus vespilloides

With growing numbers of sequenced genomes, increasing numbers of duplicate genes are uncovered. Here we examine Malvolio, a gene in the natural resistance-associated macrophage protein (Nramp) family, that has been duplicated in the subsocial beetle, Nicrophorus vespilloides, which exhibits advanced parental behavior. There is only one copy of Mvl in honey bees and Drosophila, whereas in vertebrates there are two copies that are subfunctionalized. We first compared amino acid sequences for Drosophila, beetles, mouse and humans. We found a high level of conservation between the different species, though there was greater variation in the C-terminal regions. A phylogenetic analysis across multiple insect orders suggests that Mvl has undergone several independent duplications. To examine the potential for different functions where it has been duplicated, we quantified expression levels of Mvl1 and Mvl2 in eight tissues in N. vespilloides. We found that while Mvl1 was expressed ubiquitously...