Search results for "Pigmentation"
showing 4 items of 134 documents
Dyskeratosis congenita: Report of a case with literature review
2007
Leukoplakic lesion is not uncommon in clinical practice but its occurrence as a component of a syndrome is rare. Dyskeratosis congenita is a rare genodermatosis, which is characterized by triad of skin pigmentation, nail dystrophy and leukoplakic lesion in the oral cavity. It is important for dentists to now about Dyskeratosis Congenita because these leukoplakic lesions can spontaneously undergo malignant transformation. Majority of cases have been reported in dermatology or pediatrics literature whereas only few reports have appeared in dental literature. The purpose of reporting this case with review of recent literature is to create better awareness among dentists about the multisystem m…
Oral Blue Nevus: Case Report
2016
Abstract: Aim of this research is the description of a case of palatal blue nevus and the diagnostic and therapeutic strategies to adopt when this oral lesion occurs. Nevi are benign proliferations of nevus cells either in the epithelium or in the subepithelial stroma. Blue nevus of the oral mucosa is a rare lesion. The oral blue nevi are asymptomatic and have no malignant potential. More importantly blue nevus had to be differentiated from malignant melanoma. Because is difficult to distinguish oral melanocytic nevi from melanoma we believe that any oral lesion in question should be excised and sent for histopathologic evaluation.
Sole coloration as an unusual aposematic signal in a Neotropical toad
2019
Many animals have evolved remarkable strategies to avoid predation. In diurnal, toxic harlequin toads (Atelopus) from the Amazon basin, we find a unique colour signal. Some Atelopus populations have striking red soles of the hands and feet, visible only when walking. When stationary, the toads are hard to detect despite their yellow-black dorsal coloration. Consequently, they switch between high and low conspicuousness. Interestingly, some populations lack the extra colour display of the soles. We found comprehensive support that the red coloration can act as an aposematic signal directed towards potential predators: red soles are significantly more conspicuous than soles lacking red colora…
The impact of life stage and pigment source on the evolution of novel warning signal traits
2021
Our understanding of how novel warning color traits evolve in natural populations is largely based on studies of reproductive stages and organisms with endogenously produced pigmentation. In these systems, genetic drift is often required for novel alleles to overcome strong purifying selection stemming from frequency-dependent predation and positive assortative mating. Here, we integrate data from field surveys, predation experiments, population genomics, and phenotypic correlations to explain the origin and maintenance of geographic variation in a diet-based larval pigmentation trait in the redheaded pine sawfly (Neodiprion lecontei), a pine-feeding hymenopteran. Although our experiments c…