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White giraffes: The first record of vitiligo in a wild adult giraffe

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White giraffes: The first record of vitiligo in a wild adult giraffe

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... In mammals, genetic anomalies in coat color are documented in most taxa (Abreu et al., 2013;Camargo et al., 2014;Cronemberger et al., 2018;Descalzo et al., 2021;Keener et al., 2011;McAlpine, 2021;Muller, 2017;Olson & Allen, 2019). The increase in camera trap use has recently been revealing new evidence on this phenomenon in mustelids too Gong et al., 2021;Hofmeester et al., 2021;Olson & Allen, 2019;Scrich et al., 2019). ...
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Evidence of abnormal coloration in wild animals provides useful information to better understand its adaptive function and its impact on survival. For this reason, we need to know the frequency and distribution of these abnormal phenotypes in wild populations. Here, we report two records of hypopigmentation in European pine marten Martes martes, obtained during a camera‐trapping survey on Elba Island, Central Italy. We do not know what has caused anomalous coloration of pine marten on Elba Island, but it is possible that the inbreeding may have played a role in this isolated population. Although the light coloration certainly entails an increased visibility of pine martens, it is possible that the low predator pressure and the absence of other wild carnivore populations in our study could mitigate the mortality risk due to the light phenotype. The increased use of camera traps across the world can potentially facilitate the discovery of cases of anomalous colorations in wild populations, providing an unprecedented insight into the occurrence of this phenomenon in wild mammal species. Evidence of abnormal coloration in wild animals provides useful information to better understand their adaptive function and their impact on survival. For this reason, it is useful to know the frequency and distribution of these abnormal phenotypes in wild populations. Here, we report two records of hypopigmentation in European pine marten Martes martes, obtained during a camera‐trapping survey on Elba Island, Central Italy.
... The most com mon forms of hypopigmentation are albinism (a complete absence of melanin in hair, skin, and eyes; Da Costa Toledo et al. 2014) and leucism (a total or partial loss of multi ple types of pigmentation that results in either white, pale, or patchy coloration of an animal's skin, hair, feathers, or scales; Ellegren 1997, Edelaar et al. 2011. Hypopigmenta tion can also be acquired and change progressively over an individual's life (Muller 2017). Hypopigmentation appears sometimes to be more common in certain geographic lo cations (Forrest andNaveen 2000, Edelaar et al. 2011), and the aberrant coloration caused by hypopigmentation of ten has negative consequences for an individual's fitness (Sage 1962, Ellegren 1997. ...
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Vitiligo is a dermatological disease affecting both animals and humans. It is characterized by depigmented macules of varying shape and size, originated from melanocyte destruction. Even though there are some theories tackling causation, disease etiopathology is not yet certain. Moreover, lesion areas can either increase or diminish over time, and therefore, available treatment alternatives tend to prove inconsistencies. No epidemiological data or registered cases were found for equines in Brazil. The horse in this case description displayed depigmentation areas in facial regions, including upper lip, nose and lips. However, the individual did not happen to develop any systemic alteration. Through clinical evaluation, backed by a histopathological exam, a definitive vitiligo diagnosis was obtained. However, no therapeutic plan was stipulated. The animal was accompanied for four years, during which period some affected areas diminished while others increased in size. In addition, emergence of new skin lesions was also observed during the time the animal was studied. Overall, this disease does not display alterations to organism functionality, only aesthetic changes. Therefore, treatment plans may vary from case to case, occasionally being even ruled out.
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Hypopigmentation disorders were reported in several bat species roosting in dark and sheltered roosts, but comparable records from open foliage roosts are rare. Here, we present three observations of non-albinistic hypopigmentation in two neotropical bat species. One extensively hypopigmented individual of Uroderma bilobatum was observed roosting among regular pigmented conspecifics in an open foliage roost in Panamá. Two individuals of Glossophaga soricina with a patchy hypopigmentation were incidentally mistnetted during studies in Panamá and Costa Rica. Considering the species-specific roosting habits, we briefly discuss potential implications of pigmentation disorders and aberrant visual appearance for the affected individuals.
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Though melanism has been observed in several species of North American sciurids, the occurrence of this phenotype is relatively rare in American Red Squirrels (Tamiasciurus hudsonicus). We provide the first detailed accounts of melanistic Red Squirrels observed in Nova Scotia, Canada.
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This review presents a general view of all types of melanin in all types of organisms. Melanin is frequently considered just an animal cutaneous pigment and is treated separately from similar fungal or bacterial pigments. Similarities concerning the phenol precursors and common patterns in the formation routes are discussed. All melanins are formed in a first enzymatically-controlled phase, generally a phenolase, and a second phase characterized by an uncontrolled polymerization of the oxidized intermediates. In that second phase, quinones derived from phenol oxidation play a crucial role. Concerning functions, all melanins show a common feature, a protective role, but they are not merely photoprotective pigments against UV sunlight. In pathogenic microorganisms, melanization becomes a virulence factor since melanin protects microbial cells from defense mechanisms in the infected host. In turn, some melanins are formed in tissues where sunlight radiation is not a potential threat. Then, their redox, metal chelating, or free radical scavenging properties are more important than light absorption capacity. These pigments sometimes behave as a double-edged sword, and inhibition of melanogenesis is desirable in different cells. Melanin biochemistry is an active field of research from dermatological, biomedical, cosmetical, and microbiological points of view, as well as fruit technology.
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We report the first leucistic guanaco (Lama guanicoe) in the Andes Mountains of northwestern Argentina. In January 2011, an atypical guanaco was sighted near Socompa Volcano. Reportamos el primer guanaco blanco (Lama guanicoe) en la cordillera de los Andes del noroeste de Argentina. En enero de 2011, observamos un guanaco atípico cerca del volcán Socompa.
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The social organization of giraffes (Giraffa camelopardalis) imposes a high-cost reproductive strategy on bulls, which adopt a 'roving male' tactic. Our observations on wild giraffes confirm that bulls indeed have unsynchronized rut-like periods, not unlike another tropical megaherbivore, the elephant, but on a much shorter timescale. We found profound changes in male sexual and social activities at the scale of about two weeks. This so far undescribed rutting behaviour is closely correlated with changes in androgen concentrations and appears to be driven by them. The short time scale of the changes in sexual and social activity may explain why dominance and reproductive status in male giraffe in the field seem to be unstable.
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Three new records of the rare phenomenon of leucism are presented in three Colombian bats: Carollia brevicauda, Artibeus jamaicensis and Lophostoma silvicolum. The specimen of C. brevicauda was collected with mist net in lowland forest, and the A. jamaicensis specimen was trapped manually in a cave of Santa Catalina Island. The record of L. silvicolum was obtained from a voucher specimen deposited in the Instituto Alexander von Humboldt collections. The three specimens differ from other individuals due to the irregular distribution of melanin pigments in their ventral and dorsal hair. Additionally, a list of some cases of leucism in bats, previously reported as albinism, is presented.
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The records of albino, partial albino, and leucistic individuals among four species of European Viperinae (Vipera ammodytes, Vipera aspis, Vipera seoanei, and Vipera berus) were summarized based on literature records, mu-seum material, reports of field herpetologists and herpetoculturists, and a short description of all reported speci-mens was made. For the first three species only scattered observations have been made (1, 1, and 6 reports), whereas at Vipera berus these defects proved to be more widespread (16 reports), and present an occurrence pat-tern shift to the Nordic countries. Different hypotheses are postulated on the offset geographic distribution pat-tern of albinism and leucism at this species, taking into account the differences in predation pressure and popula-tion densities between populations in Southern and Northern Europe. The possible negative effect of the color defects on the fitness and survival of the specimens carrying them is debated.
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Ontogenetic colour changes are non-reversible colour changes associated with normal progressive development of an individual of a species. This paper provides the first review of the evolutionary significance of this phenomenon in animals. Proximate mechanisms and environmental cues are briefly discussed and a conceptual framework for understanding the ultimate reasons for ontogenetic colour change is established. Changes in size, vulnerability, reproductive status, habitat and metabolism are often associated with ontogenetic colour change and can aid in understanding its adaptive significance. Neutral or non-adaptive ontogenetic colour changes due to phylogenetic inertia and developmental constraints are also considered. Existing studies of ontogenetic colour changes in marine invertebrates, terrestrial invertebrates, fish, amphibians, reptiles, birds and mammals are discussed within this framework. A need is identified for more experimental tests of hypotheses for the significance of ontogenetic colour change.
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One leucistic and one partially leucistic Antarctic fur seal Arctocephalus gazella were seen at Bouvetya during the 1996/97 austral summer. Both likely came from South Georgia, where this colour morph is common. No individuals of this colour morph were sighted during three subsequent expeditions to Bouvetya. The prevalence of this colour morph in the abundant populations of the Scotia Arc may be due to founder effect, as at least one leucistic animal was present at South Georgia when the Antarctic fur seal was close to extinction.
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We observed a light coloured female southern elephant seal juvenile (Mirounga leonina) twice at Marion Island in August 2008 and confirmed that it was leucistic rather than albinistic. Though there have been a few previous reports of light-coloured southern elephant seals, this is the first confirmed case of leucism in this species. Judged to be 1-year old, perhaps 2-years old at the most, and because we have not observed any leucistic pups at Marion Island during the past 2years despite an extensive monitoring and tagging program, we think that this animal was born at nearby Prince Edward Island or perhaps further afield at Îles Crozet.
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With its iconic appearance and historic popular appeal, the giraffe is the world's tallest living terrestrial animal and the largest ruminant. Recent years have seen much-needed new research undertaken to improve our understanding of this unique animal. Drawing together the latest research into one resource, this is a detailed exploration of current knowledge on the biology, behaviour and conservation needs of giraffe. Dagg highlights striking new data, covering topics such as species classification, the role of infrasound in communication, biological responses to external temperature changes and motherly behaviour and grief. The book discusses research into behaviour alongside practical information on captive giraffe, including diet, stereotypical behaviour, ailments and parasites, covering both problems and potential solutions associated with zoo giraffe. With giraffe becoming endangered species in Africa, the book ultimately focuses on efforts to halt population decline and the outlook for conservation measures.
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Much of the information available about the life history of the giraffe, Giraffa camelopardalis, is derived from captive studies or short‐term field studies. The coat colour of male giraffes, especially the blotches, darkens with age, but no studies have systematically mapped the colour transition with chronological age based on long‐term data. We examine the value of using darkening coat colour as a biomarker of male age. We analyzed 33 years of data from 36 male Thornicroft's giraffes, G. c. thornicroftii, living in Zambia in order to document key milestones in male development. We found that the change in male pelage colouration takes an average of 1.8 years and that males are completely covered with coal‐black blotches at an average age of 9.4 years. Using lifetime data on male deaths and disappearances, combined with cross‐sectional records on coat‐colour transformation, we conclude that the average age of death among male giraffes is about 16 years old. The maximum lifespan of male giraffes is about 22 years compared with a maximum lifespan of about 28 years for female giraffes. We conclude that the possible proximate mechanisms and adaptive significance of male coat‐colour changes should be studied in more detail.
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The Seal Rehabilitation and Research Centre (SRRC) in Pieterburen, The Netherlands, rehabilitates seals from the waters of the Wadden Sea, North Sea and Southwest Delta area. Incidental observations of albinism and melanism in common and grey seals are known from countries surrounding the North Sea. However, observations on colour aberrations have not been systematically recorded. To obtain the frequency of occurrence of these colour aberrations, we analysed data of all seals admitted to our centre over the past 38 years. In the period 1971-2008, 3000 common seals (Phoca vitulina) were rehabilitated, as well as 1200 grey seals (Halichoerus grypus). A total of five albinistic common seals and four melanistic grey seals were identified. This results in an estimated incidence of albinism in common seals of approximately 1/600, and of melanism in grey seals of approximately 1/300. The seals displayed normal behaviour, although in the albinistic animals, a photophobic reaction was observed in daylight. (C) Koninklijke Brill NV, Leiden, 2010.
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Body weight, food intake, pelage color, and testis size in Djungarian hamsters are known to show annual cycles. To analyze the environmental factors that control the annual cycle of these physiological parameters, we performed an experiment with four combinations of photoperiods and temperatures (long photoperiod and high temperature, long photoperiod and low temperature, short photoperiod and high temperature, and short photoperiod and low temperature). Short photoperiod (8L16D) induced a decrease in body weight and testis size and an increase in the ratio of food storage behavior, total hair length, and the length of white distal region of hairs (a quantitative measure of pelage color) under both low (7°C) and high (25°C) temperatures. Long photoperiod (16L8D) induced the opposite effects. Low temperature induced an increase in the amount of food intake under both long and short photoperiods. under high temperature, food intake was greater in long photoperiod than in short photoperiod. Thus, we conclude that the main environmental factor for regulating annual cycles of various parameters in the Djungarian hamster is photoperiod. Photoperiodically regulated food storage behavior seems to have an important role for the strict control of body weight and food intake.
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The development of behavior in Sprague-Dawley descendants was observed in 13 litters, and detailed qualitative and quantitative descriptions are reported. Results include information on postural development, (lying, sitting, standing), reflex figures (twitching, head waving, stretching and yawning, body flexion, righting reaction, freezing, sniffing, auditory orientation reactions, visual orientating reactions), functional activities (sleeping, consummatory behavior, locomotor activity, climbing, grooming, exploration, manipulation, digging, defecation) and social behavior. (19 ref.) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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1The question of sub-specific rank for the American grey squirrel in Britain is discussed. In America the two forms concerned show intergradation over a large area, and the definitions do not appear to be consistent. Our present animal is probably intermediate between Sciurus c. carolinensis Gmelin and S. c. leucotis Gapper.2Seasonal variations in the coat are described. Ear-tufts are present in winter. Juveniles and adults in summer coat are brownish in colour and may be confused with the red squirrel, S. vulgaris leucourus Kerr. Erythristic mutants have been observed in the New Forest area.3Albino, melanie and partially-melanie forms have been recorded in America and in Britain. The genetics of the melanic form are still not understood. The result of a cross between a female melanic and a normal grey male is described. In Britain melanics are to be found in Bedfordshire and Hertfordshire, and albinos occur in Kent, Surrey and Sussex.4Sex-ratio tables for nestlings, juveniles and adults are given. Although methods of collection may possibly influence this ratio, a slight but steady preponderance of females is recorded in all classes except 1946 nestlings. A total sex ratio for males; females of 86: 100 is given. American records show a preponderance of males over females.5The grey squirrel has two breeding seasons in Britain: one starts in early January and continues into March, and lactating females are found until late May. The second season starts in early June and continues until the end of July. No breeding females were recorded in October, November and December of any year. Males do not have a definite breeding season. First-year females do not appear to have more than one litter, but adults may have two per year. Breeding seasons in America and South Africa are compared with those for Britain.6Breeding rates for four years in Britain are compared.7Tables for litter size in America and in Britain are given. There is a suggestion that autumn litters are larger than those in spring. One hundred and forty-eight litters gave an average of 2.50 young per litter, compared with 3.23 for 55 autumn litters (Britain).8A group of squirrels kept in captivity was observed to exhibit mating “play”, but there were no pregnancies. Artificial insemination was attempted without effect. Injections of a gonadotrophic preparation were given to five animals, but no pregnancies were recorded. The provision of extra light proved impracticable as the squirrels took cover in their nest-boxes.9In 1948 breeding started among the captive stock. In this year two litters were born, one to each of the elder females. The conditions under which this occurred are described. The young were reared successfully by the parents.10The growth of young squirrels was studied. The weight at birth is estimated to be between 13–17 g. Records for growth of hair, opening of eyes, eruption of teeth and weaning are correlated with body-weights. A growth curve from young born in captivity is used to calculate age from body weight. The coat is moulted when weaning is completed. Post-weaning growth curves were plotted from captive animals. Weight records of juvenile squirrels coming in from the field were plotted month by month for comparison with the rising weight of laboratory animals, and an agreement was found.11Notes were kept over an 18-month period on the nesting activities of grey squirrels in a 34-acre patch of mixed woodland. Records showed that there is a preference for certain trees as nest sites, and showed the relation between summer and winter dreys. They also showed the danger of carrying out a census of squirrels based only on drey-counts without inspection of each drey.
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HSP70i and other stress proteins have been used in anti-tumor vaccines. This begs the question whether HSP70i plays a unique role in immune activation. We vaccinated inducible HSP70i (Hsp70-1) knockout mice and wild-type animals with optimized TRP-1, a highly immunogenic melanosomal target molecule. We were unable to induce robust and lasting depigmentation in the Hsp70-1 knockout mice, and in vivo cytolytic assays revealed a lack of cytotoxic T-lymphocyte activity. Absence of T-cell infiltration to the skin and maintenance of hair follicle melanocytes were observed. By contrast, depigmentation proceeded without interruption in mice lacking a tissue-specific constitutive isoform of HSP70 (Hsp70-2) vaccinated with TRP-2. Next, we demonstrated that HSP70i was necessary and sufficient to accelerate depigmentation in vitiligo-prone Pmel-1 mice, accompanied by lasting phenotypic changes in dendritic cell subpopulations. In summary, these studies assign a unique function to HSP70i in vitiligo and identify HSP70i as a targetable entity for treatment.
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During the last decade, coat colouration in mammals has been investigated in numerous studies. Most of these studies addressing the genetics of coat colouration were on domesticated animals. In contrast to their wild ancestors, domesticated species are often characterized by a huge allelic variability of coat-colour-associated genes. This variability results from artificial selection accepting negative pleiotropic effects linked with certain coat-colour variants. Recent studies demonstrate that this selection for coat-colour phenotypes started at the beginning of domestication. Although to date more than 300 genetic loci and more than 150 identified coat-colour-associated genes have been discovered, which influence pigmentation in various ways, the genetic pathways influencing coat colouration are still only poorly described. On the one hand, similar coat colourations observed in different species can be the product of a few conserved genes. On the other hand, different genes can be responsible for highly similar coat colourations in different individuals of a species or in different species. Therefore, any phenotypic classification of coat colouration blurs underlying differences in the genetic basis of colour variants. In this review we focus on (i) the underlying causes that have resulted in the observed increase of colour variation in domesticated animals compared to their wild ancestors, and (ii) the current state of knowledge with regard to the molecular mechanisms of colouration, with a special emphasis on when and where the different coat-colour-associated genes act.
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Genetic abnormalities of the melanin pigment system in which the synthesis of melanin is reduced or absent are called albinism. The reduction in melanin synthesis can involve the skin, hair follicle, and eye, resulting in oculocutaneous albinism (OCA), or can be localized primarily to the eye, resulting in ocular albinism (OA). At least nine types of albinisms have been described. Most types are autosomal recessive in inheritance, but one type of OA is X-linked recessive in inheritance. As can be seen from the table, some skin, hair, and eye melanin is found in most types of albinism; total absence of cutaneous and ocular melanin is found only in type IA (tyrosine-negative) OCA. Albinism is a common genetic condition. Approximately 1 in 17,000 individuals in the United States had OCA, with type IA (tyrosinase-negative) and type II (tyrosine-positive) being the most prevalent. The other types of OCA are infrequent or rare. The prevalence of OA is not well established but is thought to be considerably less than that of OCA. More than 1 per cent of the population are heterozygous for a gene producing albinism.
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All of 24 animals (dogs, cats, and horses) with vitiligo were found to have antibodies to pigmented cells that could be detected by specific immunoprecipitation of radioiodinated, detergent-soluble surface macromolecules, and by indirect immunofluorescence on viable cells. These antibodies were not detected in 17 normal animals of the same species. The antibodies were directed to an 85-kDa surface antigen selectively expressed by pigmented cells that was not present on nonpigmented control cells. These observations suggest that vitiligo in animals is an autoimmune disease mediated to pigmented cells.
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We correlated the level of vitiligo antibodies to the extent of depigmentation in thirty-two patients with vitiligo. Vitiligo antibodies were assayed by protein A-sepharose immunoprecipitation method. Antibodies were present in four of eight (50%) patients with minimal vitiligo (less than 2% body surface involved), in nine of ten (90%) patients with moderate vitiligo (2 to 5% surface involved), and in thirteen of fourteen (93%) patients with more extensive disease (greater than 5% surface involved). The level of vitiligo antibodies in the three groups expressed as a binding index was 2.9% +/- 2.03, 5.6% +/- 2.92, and 8.0% +/- 3.03 SD, respectively. These results suggest that there is a relation between the incidence and level of vitiligo antibodies and the extent of depigmentation in vitiligo.
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INTEREST in the infection of insects by parasites has been generated by the pathogenic potential of the parasite to the insect itself, or to a vertebrate host to which the parasite may be transmitted. For example, because of the effects of malaria on man, the relationships between Plasmodia and various mosquito species have received much attention1,2. An important part of the host-parasite relationship is the defence system of the host. In insects, phenoloxidase (o-diphenol: O2 oxidoreductase, EC 1.10.3.1.) has been suggested to be at least partially responsible for insect immunity and parasite resistance3-5.
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Images Fig. 1A, B Fig. 1C, D
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Melatonin in beeswax was implanted in male weasels (Mustela erminea). Brown weasels and white animals undergoing the spring change to the brown pelage and reproductive activity molted, grew a new white coat, and became reproductively quiescent after treatment. Controls retained or acquired the brown coat and developed or maintained enlarged testes. Treated weasels with pituitary autografts under the kidney capsule grew brown hair after hair growth was initiated by plucking. It is suggested that the pineal gland product, melatonin, initiates changes in the central nervous system and endocrines which result in molting, growth of the white winter pelage, and reproductive quiescence in the weasel.
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Oculocutaneous albinism (OCA) is an autosomal-recessive genetic disorder defined by hypomelanosis in the eyes, hair, and skin. Piebaldism is an autosomal-dominant congenital leukoderma associated with a white forelock. The molecular pathogeneses of these congenital pigmentary disorders have been clarified in recent years and are briefly reviewed here. The pathologic gene mutations causing OCA and piebaldism are as follows. When a mutated tyrosinase gene produces inactive, less active, or temperature-sensitive tyrosinase, its phenotype is tyrosinase-negative (type I-A), yellow-mutant (type I-B), or temperature-sensitive (type I-TS) OCA, respectively. Mutation of the P gene encoding the tyrosine-transporting membrane protein probably occurs in tyrosinase-positive OCA (type II). A heterozygous mutation of the c-kit gene encoding mast cell-stem cell growth factor receptor induces piebaldism. The molecular bases of several types of OCA and piebaldism have been elucidated by gene technology, and other gene mutations causing OCA or many other pigmentary disorders will be clarified in the near future.
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Vitiligo is a puzzling disorder characterized by a disappearance of epidermal and/or follicular melanocytes by unknown mechanisms. This very common disorder involving 1–4% of the world population is thus of great importance for the practicing dermatologist. The cellular and molecular mechanisms leading to the destruction of melanocytes in this disorder have not yet been elucidated, making it of major interest for the cell biologist involved in melanocyte research. Recent advances in this field, due largely to the availability of techniques for culturing normal human melanocytes, opened new perspectives in the understanding of vitiligo. Although vitiligo has long been considered a disorder confined to the skin, there is now good evidence that it also involves the extracutaneous compartment of the “melanocyte organ.” It is also clear that vitiligo is not only a melanocyte disorder, but that it also involves cells, such as keratinocytes and Langerhans cells, found in the epidermis and follicular epithelium. The three prevailing theories of the pathogenesis of vitiligo are the immune hypothesis, the neural hypothesis, and the self-destruct hypothesis. New hypotheses suggest that vitiligo may be due to (1) a deficiency in an unidentified melanocyte growth factor, (2) an intrinsic defect of the structure and function of the rough endoplasmic reticulum in vitiligo melanocytes, (3) abnormalities in a putative melatonin receptor on melanocytes and (4) a breakdown in free radical defense in the epidermis. None of these hypotheses has been demonstrated, and according to the available data, it is likely that the loss of epidermal and follicular melanocytes in vitiligo may be the result of several different pathogenetic mechanisms.
Wildlife census results
  • K Combes
Combes, K. (2015) Wildlife census results. Unpublished census report, Soysambu Conservancy.
Observation of a melanistic bobcat in the Ocala National Forest Florida Field Naturalist 28, 25–26.
  • J.T. Hutchinson
  • T. Hutchinson
Hutchinson, J.T. & Hutchinson, T. (2000) Observation of a melanistic bobcat in the Ocala National Forest Florida Field Naturalist 28, 25–26.
Evolutionary ecology of giraffes (Giraffa camelopardalis
  • R Brand
Brand, R. (2007) Evolutionary ecology of giraffes (Giraffa camelopardalis) in Etosha National Park, Namibia. Available at: http://hdl.handle.net/10443/1461 (Accessed on 20 January 2016).