title: The contribution of the melanin pathway to overall body pigmentation during ontogenesis of Periplaneta americana.
abstract: The most prominent colors observed in insects are black or brown, whose production is attributed to the melanin pathway. At present, though, the contribution of this pathway to overall body pigmentation throughout ontogenesis is still lacking. To address this question we examined the roles of 2 key melanin genes (TH and DDC), in embryonic and postembryonic development of the American cockroach, Periplaneta americana. Our results show that the melanin pathway does not contribute to the light brown coloration observed in the first nymphs. However, the dark brown coloration in mid nymphs and adults is produced solely from the melanin pathway. In addition, the DDC RNAi results reveal that it is dopamine melanin, not DOPA melanin, acts as the main contributor in this process. Overall, present study provides a new insight into insect pigmentation suggesting that genetic mechanisms of coloration can change during ontogenesis. Future studies of additional basal insect lineages will be required to assess in more details the generality of this phenomenon.
authors.affiliation: Biological Sciences Department, Wayne State University, Detroit, Michigan, USA.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Lemonds
authors.affiliation: Biological Sciences Department, Wayne State University, Detroit, Michigan, USA.
authors.forename: Jin
authors.initials: J
authors.lastname: Liu
authors.affiliation: Biological Sciences Department, Wayne State University, Detroit, Michigan, USA.
authors.forename: Aleksandar
authors.initials: A
authors.lastname: Popadić
mesh_terms: D000818:Animals; D004625:Embryo, Nonmammalian / Q000378:metabolism; D008543:Melanins / Q000096:biosynthesis*; D009758:Nymph / Q000378:metabolism; D010526:Periplaneta / Q000196:embryology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D010858:Pigmentation; D034622:RNA Interference; D015398:Signal Transduction
chemical_list: D008543:Melanins
keywords: DOPA decarboxylase; Periplaneta americana; insect pigmentation; melanin pathway; tyrosine hydroxylase