-
Pigment Cell & Melanoma Research May 2019Over the past century, studies of human pigmentary disorders along with mouse and zebrafish models have shed light on the many cellular functions associated with visible... (Review)
Review
Over the past century, studies of human pigmentary disorders along with mouse and zebrafish models have shed light on the many cellular functions associated with visible pigment phenotypes. This has led to numerous genes annotated with the ontology term "pigmentation" in independent human, mouse, and zebrafish databases. Comparisons among these datasets revealed that each is individually incomplete in documenting all genes involved in integument-based pigmentation phenotypes. Additionally, each database contained inherent species-specific biases in data annotation, and the term "pigmentation" did not solely reflect integument pigmentation phenotypes. This review presents a comprehensive, cross-species list of 650 genes involved in pigmentation phenotypes that was compiled with extensive manual curation of genes annotated in OMIM, MGI, ZFIN, and GO. The resulting cross-species list of genes both intrinsic and extrinsic to integument pigment cells provides a valuable tool that can be used to expand our knowledge of complex, pigmentation-associated pathways.
Topics: Animals; Gene Regulatory Networks; Genes; Genetic Association Studies; Genomics; Humans; Mutation; Pigmentation; Polymorphism, Genetic
PubMed: 30339321
DOI: 10.1111/pcmr.12743 -
Evolution; International Journal of... Mar 2022Phenotypic plasticity is predicted to evolve in environmentally variable habitats, or those experiencing a high frequency of strong selection. The evolution of...
Phenotypic plasticity is predicted to evolve in environmentally variable habitats, or those experiencing a high frequency of strong selection. The evolution of plasticity may however be constrained by costs or physiological limitations. In flowers, UV-absorbing pigmentation ameliorates UV damage to pollen, and is linked with elevated UV exposure. Whether plasticity contributes to this pattern remains unclear. Petals of Argentina anserina have larger UV-absorbing petal areas at high elevations where they experience higher and more variable UV exposure than low elevations. We measured UV-induced pigmentation plasticity in high- and low-elevation populations (hereafter, "high," "low"), and selection on pigmentation via male fitness. We dissected UV pigment biochemistry using metabolomics to explore biochemical mechanisms underlying plasticity. High displayed positive UV-induced pigmentation plasticity but low lacked plasticity. Selection favored elevated pigmentation under UV in high, supporting adaptive plasticity. In high, UV absorption was conferred by flavonoids produced in one flavonoid pathway branch. However, in low, UV absorption was associated with many compounds spanning multiple branches. Elevated plasticity was thus associated with reduced pigment diversity. These results are consistent with adaptive floral pigmentation plasticity in more extreme and variable environments. We discuss how biochemical underpinnings of pigmentation may permit or constrain the evolution of pigmentation plasticity.
Topics: Adaptation, Physiological; Flavonoids; Flowers; Pigmentation; Pollen
PubMed: 35038345
DOI: 10.1111/evo.14422 -
Philosophical Transactions of the Royal... Jul 2017Humans are a colourful species of primate, with human skin, hair and eye coloration having been influenced by a great variety of evolutionary forces throughout... (Review)
Review
Humans are a colourful species of primate, with human skin, hair and eye coloration having been influenced by a great variety of evolutionary forces throughout prehistory. Functionally naked skin has been the physical interface between the physical environment and the human body for most of the history of the genus , and hence skin coloration has been under intense natural selection. From an original condition of protective, dark, eumelanin-enriched coloration in early tropical-dwelling and , loss of melanin pigmentation occurred under natural selection as dispersed into non-tropical latitudes of Africa and Eurasia. Genes responsible for skin, hair and eye coloration appear to have been affected significantly by population bottlenecks in the course of dispersals. Because specific skin colour phenotypes can be created by different combinations of skin colour-associated genetic markers, loss of genetic variability due to genetic drift appears to have had negligible effects on the highly redundant genetic 'palette' for the skin colour. This does not appear to have been the case for hair and eye coloration, however, and these traits appear to have been more strongly influenced by genetic drift and, possibly, sexual selection.This article is part of the themed issue 'Animal coloration: production, perception, function and application'.
Topics: Animals; Biological Evolution; Eye Color; Hair Color; Human Migration; Humans; Primates; Skin Pigmentation
PubMed: 28533464
DOI: 10.1098/rstb.2016.0349 -
Current Opinion in Insect Science Oct 2016Aphids are small phloem sap-feeding insects, and show color polymorphism even within the same species. Crossing experiments have revealed the inheritance pattern of the... (Review)
Review
Aphids are small phloem sap-feeding insects, and show color polymorphism even within the same species. Crossing experiments have revealed the inheritance pattern of the body color. Coloration of aphids is determined by mainly three pigments, melanin, carotenoid, and aphin, and is influenced by both abiotic and biotic environmental factors. Aphid body colors also seem to correspond with specific biological functions under various environments. Partly due to the presence of natural enemies in the environment, a variety of physiological and behavioral responses have evolved in each color form. Thus, predation is one of the most significant external factors for maintaining body color polymorphisms. In addition, endosymbiont infections also influence aphid body color and prey-predator interactions. However, many unsolved questions remain regarding the molecular basis for and biological functions of aphid body colors. Further work, including the development of molecular techniques for comprehensive functional analysis, is needed in these areas.
Topics: Animals; Aphids; Ecosystem; Pigmentation
PubMed: 27720077
DOI: 10.1016/j.cois.2016.07.005 -
The Journal of Experimental Biology Jun 2021Carotenoids color many of the red, orange and yellow ornaments of birds and also shape avian vision. The carotenoid-pigmented oil droplets in cone photoreceptors filter...
Carotenoids color many of the red, orange and yellow ornaments of birds and also shape avian vision. The carotenoid-pigmented oil droplets in cone photoreceptors filter incoming light and are predicted to aid in color discrimination. Carotenoid use in both avian coloration and color vision raises an intriguing question: is the evolution of visual signals and signal perception linked through these pigments? Here, we explore the genetic, physiological and functional connections between these traits. Carotenoid color and droplet pigmentation share common mechanisms of metabolic conversion and are both affected by diet and immune system challenges. Yet, the time scale and magnitude of these effects differ greatly between plumage and the visual system. Recent observations suggest a link between retinal carotenoid levels and color discrimination performance, but the mechanisms underlying these associations remain unclear. Therefore, we performed a modeling exercise to ask whether and how changes in droplet carotenoid content could alter the perception of carotenoid-based plumage. This exercise revealed that changing oil droplet carotenoid concentration does not substantially affect the discrimination of carotenoid-based colors, but might change how reliably a receiver can predict the carotenoid content of an ornament. These findings suggest that, if present, a carotenoid link between signal and perception is subtle. Deconstructing this relationship will require a deeper understanding of avian visual perception and the mechanisms of color production. We highlight several areas where we see opportunities to gain new insights, including comparative genomic studies of shared mechanisms of carotenoid processing and alternative approaches to investigating color vision.
Topics: Animals; Birds; Carotenoids; Color; Color Vision; Feathers; Perception; Pigmentation
PubMed: 34142139
DOI: 10.1242/jeb.203844 -
Advances in Neonatal Care : Official... Dec 2023The observation of color is an integral part of the nursing assessment. However, the current understanding of individual skin qualities and pigmentation has not yet been...
BACKGROUND
The observation of color is an integral part of the nursing assessment. However, the current understanding of individual skin qualities and pigmentation has not yet been integrated thoroughly into foundational assessment courses, clinical education, simulation, and textbooks.
EVIDENCE ACQUISITION
Literature is scarce regarding racial groups, skin color, and physical assessment for patients across the lifespan, but even more so for the neonatal population. Historically, many nursing textbooks did not provide visual pictures or observational assessment strategies for the assessment of the Black, Indigenous, and people of color (BIPOC) population. This is improving in some nursing textbooks; however, the descriptors of and visual differences and anticipated assessment findings for the BIPOC population are not comprehensive.
RESULTS
Evidence-based assessment findings, which may occur in newborns with varying skin tones/pigmentations, are presented.
IMPLICATIONS FOR PRACTICE AND RESEARCH
The most essential step to having an accurate assessment is acknowledging the importance of color awareness. Color blindness, while thought to support inclusivity, only contributes to exclusion of one of the most important components of a person's being-their color.
Topics: Infant, Newborn; Skin; Skin Pigmentation; Indigenous Peoples; Black or African American; Racial Groups; Education, Nursing; Textbooks as Topic
PubMed: 37820356
DOI: 10.1097/ANC.0000000000001101 -
Marine Drugs Sep 2019Haloarchaea are halophilic microorganisms belonging to the archaea domain that inhabit salty environments (mainly soils and water) all over the world. Most of the genera... (Review)
Review
Haloarchaea are halophilic microorganisms belonging to the archaea domain that inhabit salty environments (mainly soils and water) all over the world. Most of the genera included in this group can produce carotenoids at significant concentrations (even wild-type strains). The major carotenoid produced by the cells is bacterioruberin (and its derivatives), which is only produced by this kind of microbes and few bacteria, like . Nevertheless, the understanding of carotenoid metabolism in haloarchaea, its regulation, and the roles of carotenoid derivatives in this group of extreme microorganisms remains mostly unrevealed. Besides, potential biotechnological uses of haloarchaeal pigments are poorly explored. This work summarises what it has been described so far about carotenoids from haloarchaea and their production at mid- and large-scale, paying special attention to the most recent findings on the potential uses of haloarchaeal pigments in biomedicine.
Topics: Animals; Archaea; Bacteria; Biotechnology; Carotenoids; Extreme Environments; Humans; Pigmentation
PubMed: 31500208
DOI: 10.3390/md17090524 -
Biological Reviews of the Cambridge... Aug 2023Vertebrate pigmentation patterns are amongst the best characterised model systems for studying the genetic basis of adaptive evolution. The wealth of available data on...
Vertebrate pigmentation patterns are amongst the best characterised model systems for studying the genetic basis of adaptive evolution. The wealth of available data on the genetic basis for pigmentation evolution allows for analysis of trends and quantitative testing of evolutionary hypotheses. We employed Gephebase, a database of genetic variants associated with natural and domesticated trait variation, to examine trends in how cis-regulatory and coding mutations contribute to vertebrate pigmentation phenotypes, as well as factors that favour one mutation type over the other. We found that studies with lower ascertainment bias identified higher proportions of cis-regulatory mutations, and that cis-regulatory mutations were more common amongst animals harbouring a higher number of pigment cell classes. We classified pigmentation traits firstly according to their physiological basis and secondly according to whether they affect colour or pattern, and identified that carotenoid-based pigmentation and variation in pattern boundaries are preferentially associated with cis-regulatory change. We also classified genes according to their developmental, cellular, and molecular functions. We found a greater proportion of cis-regulatory mutations in genes implicated in upstream developmental processes compared to those involved in downstream cellular functions, and that ligands were associated with a higher proportion of cis-regulatory mutations than their respective receptors. Based on these trends, we discuss future directions for research in vertebrate pigmentation evolution.
Topics: Animals; Vertebrates; Genetic Loci; Mutation; Pigmentation; Phenotype
PubMed: 37017088
DOI: 10.1111/brv.12952 -
Phlebology Jul 2020Chronic venous insufficiency causes skin pigmentation of the leg ranging from small patches of mild dyschromia to extensive areas of severe skin pigmentation. It is...
INTRODUCTION
Chronic venous insufficiency causes skin pigmentation of the leg ranging from small patches of mild dyschromia to extensive areas of severe skin pigmentation. It is thought that the pigmentation is mainly due to haemosiderin or melanin deposition. Erythrodiapedesis which occurs as a result of venular hypertension causes erythrocytes to migrate across the microvascular network into the dermis.
METHODS
We categorized the grading of pigmentation into four grades: +, few spots; ++, pigmentation over gaiter area; +++, pigmentation involving leg and ankle; ++++, heavily pigmented (dark). Skin biopsies were taken from the patient while undergoing surgery; two biopsies were taken from each patient, one from apparently normal skin and other from the site of pigmentation. A total of 45 patients diagnosed as chronic venous insufficiency with pigmentation were included in the study and five patients included in control. The biopsy specimens were sent to pathology department for H&E, Perls stain and IHC for S100.
RESULTS
Majority of cases, i.e. 62% of limbs fall under (++) grade of pigmentation, followed by (+) grade of pigmentation in 20%, while (+++) and (++++) constitute 9% of the cases each. Increased melanin deposition was seen in 40 pigmented skin biopsies and 3 normal skin biopsies from the case group, and normal melanin deposition was seen in all the non-varicose controls.
CONCLUSION
We have tried to categorize pigmentation in chronic venous insufficiency into four grades. As the grade of pigmentation increases the per cent of cases with ulceration is increasing. It was observed that presence of melanin deposition irrespective of the grade of pigmentation was distributed more towards the advanced clinical classification (C5 and C6).
Topics: Adult; Biopsy; Cell Movement; Chronic Disease; Erythrocytes; Female; Hemosiderin; Humans; Leg; Male; Melanins; Microcirculation; Pigmentation; Severity of Illness Index; Skin; Skin Pigmentation; Venous Insufficiency
PubMed: 31699007
DOI: 10.1177/0268355519885471 -
Poultry Science Aug 2021Eggshell color is an important shell quality trait that influences consumer preference. It is also of particular importance with respect to sexual signaling and the... (Review)
Review
Eggshell color is an important shell quality trait that influences consumer preference. It is also of particular importance with respect to sexual signaling and the physiological and mechanical properties of shell pigment. Pigments include protoporphyrin IX, biliverdin, and traces of biliverdin zinc chelates, with brown eggs being notably rich in protoporphyrin IX, the synthesis of which has a marked effect on the intensity of brown eggshell color. This pigment is initially synthesized in the eggshell gland within the oviduct of laying hens and is subsequently deposited throughout the cuticular and calcareous layers of brown eggshell. In this review, we describe the factors affecting brown eggshell color and potential targets for the regulation of pigment synthesis. Protoporphyrin IX synthesis might be compromised by synthetase-mediated pigment synthesis, the redox status of the female birds, and regulation of the nuclear transcription factors associated with δ-aminolevulinic acid synthetase1. We believe that this review will provide a valuable reference for those engaged in studying eggshell depigmentation.
Topics: Animals; Biliverdine; Chickens; Egg Shell; Female; Ovum; Pigmentation
PubMed: 34214744
DOI: 10.1016/j.psj.2021.101273