Pigment Deposition Research Articles

Clinical and mutational signatures of CRB1-associated retinopathies: a multicentre study

BackgroundTo delineate the clinical and mutational signatures of patients with CRB1-associated retinopathies.MethodsThis multicentre retrospective cohort study involved 40 patients with CRB1 mutations and 40 age-matched and gender-matched inherited retinal diseases...

Bilateral hip ochronosis, an unsuspected diagnosis in polyarticular pain: A case report

Alkaptonuria is a rare metabolic disorder characterized by the accumulation of homogentisic acid, leading to the deposition of blackish pigment in cartilage and soft tissue, known as ochronosis. This can mimic multiple joint pathologies and is a diagnosis of exclusion. We describe the case of a 52-year-old woman who had a total hip replacement after experiencing left hip pain for which oral medications were unable to provide relief. Unexpectedly, during the procedure, a blackish tissue was noticed. This led to a histological examination and the confirmation of the ochronosis diagnosis. The patient’s medical history revealed a number of malignancies, but no previous metabolic illness diagnoses. Subsequent follow-up revealed rapid-onset pain in other joints, leading to a similar diagnosis of polyarticular ochronosis in the right hip, knees, spine, and shoulders. This highlights how difficult it is to treat this condition. This case underscores the importance of considering ochronosis as a differential diagnosis in patients with chronic polyarticular pain. Current treatment consists of initial non-surgical measures, including physical therapy and analgesics. If there is no improvement, treatment would be joint arthroplasty. Awareness among orthopedic surgeons and histopathological examination of tissues is crucial for the accurate diagnosis and management of ochronosis.

TRANSPARENT TESTA 16 collaborates with the MYB-bHLH-WD40 transcriptional complex to produce brown fiber cotton.

Naturally colored cotton (NCC; Gossypium spp.) does not require additional chemical dyeing and is an environmentally friendly textile material with great research potential and applications. Our previous study using linkage and association mapping identified TRANSPARENT TESTA 2 (Gh_TT2) as acting on the proanthocyanin synthesis pathway. However, limited information is available about the genetic regulatory network of NCC. Here, we verified the effectiveness of Gh_TT2 and the roles of Gh_TT2 and red foliated mutant gene (Re) in pigment formation and deposition of brown fiber cotton (BFC). Variations in Gh_TT2 derived from interspecific hybridization between Gossypium barbadense acc. Pima 90-53 and Gossypium hirsutum acc. Handan208 resulted in gene expression differences, thereby causing phenotypic variation. Additionally, the MYB-bHLH-WD complex was found to be negatively modulated by TRANSPARENT TESTA 16/ARABIDOPSIS BSISTER (TT16/ABS). RNA-seq suggested that differential expression of homologous genes of key enzymes in the proanthocyanin synthesis pathway strongly contributes to the color rendering of natural dark brown and light brown cotton. Our study proposes a regulatory model in BFC, which will provide theoretical guidance for the genetic improvement of NCC.

TFE3-Rearranged Tumors of the Kidney: An Emerging Conundrum

Background: Identical translocations involving the TFE3 gene and various partners have been found in both renal and soft tissue tumors, like alveolar soft part sarcoma (ASPSCR1), ossifying fibromyxoid tumor (PHF1), epithelioid hemangioendothelioma, and the clear cell stromal tumor of the lung (YAP1). Methods: Herein, we review in detail the clinicopathologic and molecular data of TFE3-rearranged renal tumors and propose our perspective, which may shed light on this emerging conundrum. Results: Among the kidney tumors carrying TFE3 translocations, most are morphologically heterogeneous carcinomas labeling for the tubular marker PAX8. The others are mesenchymal neoplasms known as PEComas, characterized by epithelioid cells co-expressing smooth muscle actin, cathepsin-K, melanogenesis markers, and sometimes melanin pigment deposition. Over the past 30 years, numerous TFE3 fusion partners have been identified, with ASPL/ASPSCR1, PRCC, SFPQ/PSF, and NONO being the most frequent. Conclusions: It is not well understood why similar gene fusions can give rise to renal tumors with different morpho-immunophenotypes, which may contribute to the recent disagreement regarding their classification. However, as these two entities, respectively, epithelial and mesenchymal in nature, are widely recognized by the pathology community and their clinicopathologic features well established, we overall believe it is still better to retain the names TFE3-rearranged renal cell carcinoma and TFE3-rearranged PEComa.

Phakic intraocular lens exchange due to severe uveitis/inflammation: case report

Introduction: Phakic intraocular lenses (IOLs) provide excellent visual and refractive outcomes with a high safety profile. This report illustrates a case of a rare episode of severe anterior segment inflammation after iris-claw foldable lens implantation, which required surgical reintervention. Patient and Clinical Findings: A 22-year-old woman was submitted to Artiflex implantation for the correction of myopia. Three months postoperatively, a severe anterior segment inflammation developed with pigment deposition, pupillary membrane formation, and decreased visual acuity in the left eye. Diagnosis, Intervention, and Outcomes: Given the nonresponse to medical treatment (topical and systemic corticosteroid for 3 months), surgical explantation of the IOL with peeling of a pigmentary membrane over the crystalline lens was performed. During a 24-month follow-up period, the patient was monitored to exclude the development of cataract or glaucoma. Afterward, an implantable collamer lens was implanted with an uneventful intraoperative and postoperative period. During the long-term follow-up, no further pigment dispersion, uveitis, or cataract was described. Conclusions: Persistent anterior uveitis with pigmentary membrane formation after iris-claw lens implantation is a rare complication. IOL explantation needs to be considered to prevent further sequelae after severe uveitis when the situation is unresponsive to medical treatment.

Oral Tranexamic Acid for Prevention and Treatment of Postinflammatory Hyperpigmentation.

Postinflammatory hyperpigmentation (PIH) is a skin disorder characterized by hyperpigmentation resulting from heightened inflammation and/or damage to the basement membrane, melanocytes, and keratinocytes, leading to abnormal and excessive pigment deposition. Oral tranexamic acid (TXA), originally used as an antifibrinolytic for managing excessive bleeding, has garnered attention for its demonstrated safety and efficacy in treating melasma. There is a growing body of evidence regarding the use of TXA in the treatment of PIH. To review the mechanism of action of oral TXA in treating PIH and examine the use of oral TXA in preventing and/or treating PIH associated with laser-based and light-based treatments in individuals with skin color. Review of relevant articles from 2000 to present found in the Cochrane Library, PubMed, Embase, and Google Scholar, regarding the use of oral TXA in the treatment of PIH. Studies reviewed investigated the efficacy of oral tranexamic acid (TXA) in treating postinflammatory hyperpigmentation (PIH) and use in preventing PIH when used in conjunction with other treatments. All studies demonstrated significant improvement in PIH without significant adverse effects and side effects. Oral tranexamic acid is emerging as a safe and effective treatment in the prevention and treatment of postinflammatory hyperpigmentation.

What is “eczema”?

AbstractEczema is the most common category of inflammatory skin disorders as dermatologists see many patients with eczematous diseases in daily practice. It is characterized by the three major morphological features: multiple‐pinpoint condition, polymorphism, and itch. To describe polymorphism, “eczema triangle” has been used in German/Japanese dermatology. The multiple pinpoints correspond to numerous tiny foci from which individual papules/vesicles arise. The polymorphism betrays composition of erythema, papule, seropapule, vesicle, pustule, scale, and crust, which are seen in acute eczema. Meanwhile, chronic eczema is represented by lichenification and hyperpigmentation, and possibly by hypopigmentation. In acute eczema, spongiosis is associated with overproduction of hyaluronic acid, secretion of self‐protective galectin‐7, and decreased expression of E‐cadherin. In the upper dermis, Th1/Tc1 or Th2/Tc2, and additional Th17, Th22, and/or Tc22 infiltrate, depending on each eczematous disease. Innate lymphoid cells are also involved in the formation of eczema. In chronic eczema, periostin contributes to remodeling of inflammatory skin with dermal fibrosis, and epidermal melanogenesis and dermal pigment deposition result in hyperpigmentation. Finally, eczematous diseases are potentially associated with increased risk of comorbidities, including not only other allergic diseases but also coronary heart disease and mental problems such as depression. Although the original word for eczema is derived from old Greek “ekzein,” eczema remains a major target of modern science and novel therapies.

Exogenous Melatonin Alleviates NaCl Injury by Influencing Stomatal Morphology, Photosynthetic Performance, and Antioxidant Balance in Maize.

Maize (Zea mays L.) is sensitive to salt stress, especially during seed germination and seedling morphogenesis, which limits maize growth and productivity formation. As a novel recognized plant hormone, melatonin (MT) participates in multiple growth and developmental processes and mediates biotic/abiotic stress responses, yet the effects of salt stress on maize seedlings remain unclear. Herein, we investigated the effects of 150 μM exogenous MT on multiple phenotypes and physiologic metabolisms in three-leaf seedlings across eight maize inbred lines under 180 mM NaCl salt stress, including growth parameters, stomatal morphology, photosynthetic metabolisms, antioxidant enzyme activities, and reactive oxygen species (ROS). Meanwhile, the six gene expression levels controlling antioxidant enzyme activities and photosynthetic pigment biosynthesis in two materials with contrasting salt resistance were examined for all treatments to explore the possible molecular mechanism of exogenous MT alleviating salt injury in maize. The results showed that 150 μM exogenous MT application protected membrane integrity and reduced ROS accumulation by activating the antioxidant system in leaves of maize seedlings under salt stress, their relative conductivity and H2O2 level average reduced by 20.91% and 17.22%, while the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) averaged increased by 13.90%, 17.02%, 22.00%, and 14.24% relative to salt stress alone. The improvement of stomatal size and the deposition of photosynthetic pigments were more favorable to enhancing photosynthesis in leaves when these seedlings treated with MT application under salt stress, their stomatal size, chlorophyll content, and net photosynthetic rate averaged increased by 11.60%, 19.64%, and 27.62%. Additionally, Gene expression analysis showed that MT stimulation significantly increased the expression of antioxidant enzyme genes (Zm00001d009990, Zm00001d047479, Zm00001d014848, and Zm00001d007234) and photosynthetic pigment biosynthesis genes (Zm00001d011819 and Zm00001d017766) under salt stress. At the same time, 150 μM MT significantly promoted seedling growth and biomass accumulation. In conclusion, our study may unravel crucial evidence of the role of MT in maize seedlings against salt stress, which can provide a novel strategy for improving maize salt stress resistance.

A New Method Proposed for the Estimation of Exposure to Atmospheric Pollution through the Analysis of Black Pigments on the Lung Surface

Megacities can be considered excellent laboratories for studying the effects of the urban environment on human health. Typically, exposure to pollution is estimated according to daily or annual averages of pollutant concentrations, collected at monitoring stations, using satellite data for remote sensing of pollutant levels, considering proximity to major roads, or through personal exposure monitoring with portable sensors. However, these approaches fall short in identifying individual exposure values over a lifetime. It is well established that individuals living in large urban areas inhale atmospheric particles containing carbonaceous components, resulting in the deposition of black pigments in lung tissue, known as black carbon or anthracosis. This study aims to detail the procedures for assessing the deposition of such pigments, which serve as an estimate of an individual’s exposure to atmospheric pollution particles. Data collection involves administering detailed questionnaires and capturing lung images in the autopsy room. The analysis is based on macroscopic quantification of black pigments, supplemented by an evaluation of personal habits and the clinical histories of the individuals. This method of estimating lifetime exposure to inhaled particles provides a valuable tool for understanding the correlation between urban living and its potential health effects.

Histopathology based study of Nile tilapia fish (Oreochromis niloticus) as a biomarker for water pollution evaluation in the southern gulf of Lake Tana, Ethiopia

In the past decade, the increasing distribution of pollutants in the aquatic environment has been observed, causing integrative effects on fish. Likewise, due to anthropogenic activities, the southern gulf of Lake Tana is an impacted region, and the production of Nile tilapia fish is reduced. For this reason, the aim of this study was to conduct a histopathological-based study of 48 Nile tilapia fishes’ health status at the southern gulf of Lake Tana and aquaculture using a cross-sectional study from February 2023 to May 2023. The study evaluated the histopathology of the gill, liver, gonads, and spleen organs using descriptive statistics accompanied by a 2 × 2 contingency table and t-test analysis. During the study, different histological alterations were detected, and the numbers of fish affected by a specific histological alteration were presented as percentage prevalence; hence, from the total fish examined, hyperplasia (54.15%), followed by pigment deposits (52%), hemorrhage (50%), and immune cell infiltration (50%), respectively, were the most frequently detected alterations. However, Nile tilapias from the southern gulf of Lake Tana were 1.4 (odds ratio) times more likely to show histopathological alterations than those from aquaculture, although statistically, was not significant (p > 0.05). In addition, the study found the mean value of the fish index (95.3) and regressive indices of the gill (13.6), liver (14.8), and gonad (12.3); moreover, the inflammatory indices of the spleen organ (11.3) and mean severity grade value of the gill (2.35) and gonad (1.7) organs, respectively, were obtained from the southern gulf of Lake Tana, and all those values were significantly higher (p < 0.05) from this site as compared to the aquaculture. In general, it has been found that tilapias from the southern gulf of Lake Tana showed higher pathological severity as compared with aquaculture. Among the four target organs evaluated, liver organs were observed to be the most damaged, while gonads were the least impacted organs. Therefore, it has been concluded that tilapia fish are living in abnormal conditions, so to ensure a sustainable fishery, water pollutant sources from Bahirdar city must receive proper attention, and future studies should consider age differences, seasonal variation, and the detection of specific pollutants.

Analysis of PDE6G mutations in a patient with retinitis pigmentosa

BackgroundMutations in PDE6A and PDE6B are known to cause autosomal recessive RP in humans, On the other hand, mutations in PDE6G are rare but can lead to severe early-onset RP.Case presentationAn 8-year-old Chinese boy was referred to our hospital for poor vision issues. Refraction with cycloplegia showed high hyperopia with astigmatism both eyes. Funduscopic examination revealed typical bone spicule-type pigment deposits in the periphery and midperiphery. The patient was given glasses and a whole exome sequencing containing mitochondrial genes was performed. The results of genetic testing showed that there was a heterozygous frameshift mutation and a segment deletion in the proband’s PDE6G gene. Analysis of the parental genes showed that frameshift mutation was inherited from the proband’s mother and segment deletion from his father.ConclusionsIn this paper, we give a firsthand report that the complex heterozygous mutations of PDE6G gene can causes autosomal recessiveRP (arRP), which expands the understanding of the pathogenic genes of RP.

A novel compound heterozygous variant of MYO7A in Usher syndrome type 1

Usher syndrome (USH) is a recessive genetic disorder manifested by congenital sensorineural hearing loss and progressive retinitis pigmentosa, which leads to audiovisual impairment. We report a patient with Usher syndrome type 1 with new compound heterozygous MYO7A variants. A total of four members from the USH family were included. Medical history and retinal examinations were taken and genomic DNA from peripheral blood was extracted in the proband and other members. 381 retinal disease-associated genes were screened using targeted sequence capture array technology and Sanger sequencing was used to confirm the screening results. Scanning laser ophthalmoscope showed bone spicule pigmentary deposits in the mid-peripheral retina and whitish and thin retinal blood vessels especially in the arterioles. Optical coherence tomography showed that the centrality of the macular ellipsoid band disappeared in both eyes, and only remained near the fovea. Visual field examination showed a progressive loss of the visual field in a concentric pattern in both eyes. The electroretinography showed a significant decrease in the amplitudes of a- and b-waves in the scotopic and photopic condition. DNA sequencing identified the compound heterozygous variants including c.1003+1G > A: p. (?) and c.5957_5958del: p.G1987Lfs*50 of MYO7A, with the latter being novel. In this study, we found a novel compound heterozygous variant in MYO7A, which enriched the mutation spectrum and expanded our understanding of the heterogeneity of phenotype and genotype of Usher syndrome type 1.

Adaption of in vitro and in chemico phototoxicity tests for tattoo pigments and the effect of adsorption of the phototoxic contaminant benzo[a]pyrene to carbon black

Phototoxicity plays an important role in tattoo toxicology due to the skin's daily exposure to sunlight and the permanent deposition of pigments in skin. Here, we investigated in chemico reactive oxygen species generation using 2′,7′-dichlorodihydrofluorescein diacetate and in vitro phototoxicity towards skin fibroblasts based on the OECD Test Guideline 432.Proficiency substances, titanium dioxide (TiO2, anatase 30 nm, anatase 100 nm, rutile 30 nm), pigment red 22 (PR 22) with and without purification and carbon black (CB) were investigated. Phototoxic properties of benzo[a]pyrene (B[a]P) were investigated with and without adsorption to CB. Pigments were characterised by dynamic light scattering.All proficiency substances except for norfloxacin were predicted successfully and only TiO2 anatase exhibited phototoxicity in the cell-based approach. B[a]P showed the expected phototoxicity in contrast to B[a]P bound to carbon black. Upon UVA irradiation, only TiO2 pigment anatase and PR 22 generated ROS in the cell-free assay. DLS measurements showed a high degree of polydispersity/agglomeration.OECD Test Guideline 432 should be applied with an incubation time of 24 h when testing highly insoluble pigments. The in chemico ROS assay introduced below might serve as a quick screening test but may be further adapted to predict the in vitro outcome.

Transcriptomic and Metabolomic Analyses Reveal Molecular Regulatory Networks for Pigmentation Deposition in Sheep.

Domestic animals have multiple phenotypes of skin and coat color, which arise from different genes and their products, such as proteins and metabolites responsible with melanin deposition. However, the complex regulatory network of melanin synthesis remains to be fully unraveled. Here, the skin and tongue tissues of Liangshan black sheep (black group) and Liangshan semi-fine-wool sheep (pink group) were collected, stained with hematoxylin-eosin (HE) and Masson-Fontana, and the transcriptomic and metabolomic data were further analyzed. We found a large deposit of melanin granules in the epidermis of the black skin and tongue. Transcriptome and metabolome analysis identified 744 differentially expressed genes (DEGs) and 443 differentially expressed metabolites (DEMs) between the pink and black groups. Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) enrichment analyses revealed the DEGs and DEMs were mainly enriched in the pathways of secondary metabolic processes, melanin biosynthesis processes, melanin metabolism processes, melanosome membranes, pigment granule membranes, melanosome, tyrosine metabolism, and melanogenesis. Notably, we revealed the gene ENSARG00020006042 may be a family member of YWHAs and involved in regulating melanin deposition. Furthermore, several essential genes (TYR, TYRP1, DCT, PMEL, MLANA, SLC45A2) were significantly associated with metabolite prostaglandins and compounds involved in sheep pigmentation. These findings provide new evidence of the strong correlation between prostaglandins and related compounds and key genes that regulate sheep melanin synthesis, furthering our understanding of the regulatory mechanisms and molecular breeding of pigmentation in sheep.

Integrative Transcriptomic and Metabolic Analyses Reveal That Flavonoid Biosynthesis Is the Key Pathway Regulating Pigment Deposition in Naturally Brown Cotton Fibers.

Brown cotton is a major cultivar of naturally colored cotton, and brown cotton fibers (BCFs) are widely utilized as raw materials for textile industry production due to their advantages of being green and dyeing-pollution-free. However, the mechanisms underlying the pigmentation in fibers are still poorly understood, which significantly limits their extensive applications in related fields. In this study, we conducted a multidimensional comparative analysis of the transcriptomes and metabolomes between brown and white fibers at different developmental periods to identify the key genes and pathways regulating the pigment deposition. The transcriptomic results indicated that the pathways of flavonoid biosynthesis and phenylpropanoid biosynthesis were significantly enriched regulatory pathways, especially in the late development periods of fiber pigmentation; furthermore, the genes distributed in the pathways of PAL, CHS, F3H, DFR, ANR, and UFGT were identified as significantly up-regulated genes. The metabolic results showed that six metabolites, namely (-)-Epigallocatechin, Apiin, Cyanidin-3-O-glucoside, Gallocatechin, Myricetin, and Poncirin, were significantly accumulated in brown fibers but not in white fibers. Integrative analysis of the transcriptomic and metabolomic data demonstrated a possible regulatory network potentially regulating the pigment deposition, in which three MYB transcription factors promote the expression levels of flavonoid biosynthesis genes, thereby inducing the content increase in (-)-Epigallocatechin, Cyanidin-3-O-glucoside, Gallocatechin, and Myricetin in BCFs. Our findings provide new insights into the pigment deposition mechanism in BCFs and offer references for genetic engineering and breeding of colored cotton materials.

Ring and flower in the eye – An incidental finding of Wilson disease in a case of diabetic retinopathy: A case report

This is to report a rare case of Wilson disease (WD) with Kayser–Fleischer (KF) ring with sunflower cataract along with diabetic retinopathy. A 43-year-old male patient presented to the comprehensive clinic with a chief complaint of diminution of vision of both eyes since 8 months. On ocular examination, the cornea showed golden brown color pigment deposition in the Descemet membrane, indicative of KF ring, which is a pathognomonic feature of WD. There was brown plaque or spoke-like radial opacities on the anterior lens capsule in both eyes, which gives sunflower appearance, which is also a feature of WD. The posterior segment revealed diabetic retinopathy in both eyes. Serum ceruloplasmin was reduced, and the bilirubin level was mildly raised. Liver function test was mildly altered. Urine excretory copper levels were raised. Ultrasonography of the abdomen and pelvis revealed liver cirrhosis with portal hypertension, splenomegaly, gross ascites, and gall bladder calculi. This is a rare case of WD with KF ring with sunflower cataract with diabetic retinopathy in both eyes. Slit lamp examination is mandatory to diagnose it as WD in the presence of KF ring.

Symptomatic pigment dispersion with intraocular pressure elevation attributed to intracameral moxifloxacin after open-globe injury

Background: Intracameral moxifloxacin is commonly used following intraocular surgery to prevent endophthalmitis. Pigment dispersion is a rare complication of moxifloxacin use that has mainly been reported following systemic administration. Case presentation: We report a case of unilateral pigment dispersion three weeks after open-globe repair with intracameral moxifloxacin presenting with pain, redness, photophobia, elevated intraocular pressure, marked pigment liberation, new iris transillumination defects and pigment deposits on the anterior iris surface. Conclusion: Symptomatic unilateral pigment dispersion with IOP elevation following intracameral moxifloxacin is a rare entity, but it is a crucial complication for clinicians to be aware of as intracameral antibiotic use following intraocular surgery becomes more frequent.

A Network of Circular RNA and MicroRNA Sequencing Provides Insights into Pigment Deposition of Changshun Blue Eggshell Chickens.

Eggshell color plays important biological roles and attracts the attention of both egg retailers and researchers. However, whether non-coding RNAs are involved in pigment deposition among different eggshell colors remains unknown. In this study, RNA sequencing was used to analyse the uterine gland transcriptome (CircRNA and miRNA) of Changshun chicken blue-shell hens producing four different eggshell color eggs including dark blue PK(DB) and light blue (LB), dark brown and greenish (between blue and pink, DP) and pink (p). We found that miR-192-x, targeting SLC16a7, was expressed in DB, DP, and LB groups compared with the PK group, which indicates that miR-192-x may play a role in the blue eggshell color. KEGG and GO analyses showed that the "metabolic pathways" with targeted genes such BLVRA and HMOX1 were detected in dark and light blue color eggshell chickens, which confirms the different ratios of biliverdin and HO-1 involved in the deposition of blue color. As annotated by connectivity analysis, RASGRF1 and RASGRF2, belonging to the RASGRF family, are involved in the Ras signaling pathway, which plays an important role in cell growth, differentiation, metastasis and apoptosis. Our findings enrich the database of circRNA, miRNAs and genes for chicken uterine tissue, which will be useful in accelerating molecular selection for blue eggshell color layers.

Pseudofilariasis, a Presenting Sign of Alkaptonuria.

To report the association of Pseudofilariasis as a presenting sign of Alkaptonuria. Case Report. A 49-year-old Indian man was referred because of wormlike objects in his left conjunctiva. Ocular and family history was non-contributory. He had not been to India in 15 years. Past medical history revealed hypertension, hypercholesterolemia, arthritis, and a myocardial infarct. He had undergone two stents, bilateral Achilles tendon repairs and bilateral knee replacements. ROS showed longstanding back stiffness and pain. On ocular examination the vision was 20/25 in each eye and positive findings were in the left eye bulbar conjunctival which showed stationary black vermiform (filarial in appearance) foreign bodies along with 2 small corneal limbal pigmented deposits. Conjunctival biopsy showed dilated lymph channels with interstitial proteinaceous material of a light brown color consistent with Ochronotic pigment; hence diagnostic of Alkaptonuria. Pseudofilariasis may be a presenting sign of Alkaptonuria and occur years before a clinical diagnosis is made. Filariasis is always involves white worms and never black. Knowing the ophthalmic signs of this rare disease may lead to an accurate diagnosis earlier thusly avoiding unnecessary tests and examinations.

Identification of candidate genes associated with primary feathers of tianfu nonghua ducks based on Genome-wide association studies

The primary feathers of ducks have important economic value in the poultry industry. This study quantified the primary feather phenotype of Nonghua ducks, including the primary feathers' length, area, distribution of black spots, and feather symmetry. And genome-wide association analysis was used to screen candidate genes that affect the primary feather traits. The genome-wide association study (GWAS) results identified the genetic region related to feather length (FL) on chromosome 2. Through Linkage disequilibrium (LD) analysis, candidate regions (chr2: 115,246,393-116,501,448 bp) were identified and were further annotated to 5 genes: MRS2, GPLD1, ALDH5A1, KIAA0319, and ATP9B. Secondly, candidate regions related to feather black spots were identified on chromosome 21. Through LD analysis, the candidate regions (chr21: 163,552-2,183,853 bp) were screened and further annotated to 47 genes. Among them, STK4, CCN5, and YWHAB genes were related to melanin-related pathways or pigment deposition, which may be key genes affecting the distribution of black spots on feathers. In addition, we also screened 125 genes on multiple chromosomes that may be related to feather symmetry. Among them, significant SNPs on chromosome 1 were further identified as candidate regions (chr1: 142,118,209-142,223,605 bp) through LD analysis and annotated into 2 genes, TGFBRAP1 and LOC113839965. These results reported the genetic basis of the primary feather from multiple phenotypes, and offered valuable insights into the genetic basis for the growth and development of duck feathers and feather color pattern.