Genetic Basis and Evolution of Structural Color Polymorphism in an Australian Songbird.

Island organisms often evolve phenotypes divergent from their mainland counterparts, providing a useful system for studying adaptation under differential selection. In the white-winged fairywren (Malurus leucopterus), subspecies on two islands have a black nuptial plumage whereas the subspecies on the Australian mainland has a blue nuptial plumage. The black subspecies have a feather nanostructure that could in principle produce a blue structural color, suggesting a blue ancestor. An earlier study proposed independent evolution of melanism on the islands based on the history of subspecies divergence. However, the genetic basis of melanism and the origin of color differentiation in this group are still unknown. Here, we used whole-genome resequencing to investigate the genetic basis of melanism by comparing the blue and black M. leucopterus subspecies to identify highly divergent genomic regions. We identified a well-known pigmentation gene ASIP and four candidate genes that may contribute to feather nanostructure development. Contrary to the prediction of convergent evolution of island melanism, we detected signatures of a selective sweep in genomic regions containing ASIP and SCUBE2 not in the black subspecies but in the blue subspecies, which possesses many derived SNPs in these regions, suggesting that the mainland subspecies has re-evolved a blue plumage from a black ancestor. This proposed re-evolution was likely driven by a preexisting female preference. Our findings provide new insight into the evolution of plumage coloration in island versus continental populations, and, importantly, we identify candidate genes that likely play roles in the development and evolution of feather structural coloration.

Dry eye disease in systemic lupus erythematosus: a cross sectional study.

AIM: To explore ocular surface manifestations of dry eye disease (DED) and its influencing factors in systemic lupus erythematosus (SLE) patients. METHODS: Ophthalmological examinations were conducted in SLE patients (n=43) and controls (n=41), including Ocular Surface Disease Index (OSDI), objective scatter index (OSI), tear meniscus height (TMH), lipid layer thickness (LLT), non-invasive Keratograph tear breakup time (NIKBUT), corneal fluorescein score (CFS), Schirmer I test. DED was diagnosed according to the Tear Film and Ocular Surface Society Dry Eye Workshop II Criteria. SLE patients were further divided into DED group and non-DED group, the disease activity, clinical manifestations and laboratory investigations were compared between the two groups. The disease activity was evaluated by Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K). Receiver operative characteristic (ROC) curve and multiple-factor binary logistic regression were performed. RESULTS: SLE patients showed higher OSDI [9.1 (2.8-15.9) vs 6.3 (2.2-7.5), P=0.035], higher OSI [1.67 (1.09-2.60) vs 0.96 (0.87-1.60), P=0.001], higher CFS [1 (0-2) vs 0 (0-1), P=0.001], lower LLT [65 (42-100) vs 100 (79.5-100), P=0.010], and lower NIKBUT [8.03 (4.02-9.73) vs 9.67 (5.26-12.71), P=0.030] than controls. The 32.6% of SLE patients had DED, which was higher than 12.2% of healthy controls. DED group showed higher SLEDAI-2K score [9.7±6.1 vs 5.4±3.4, P=0.025], higher anti-cardiolipin antibody (ACL) [8.7 (3.5-13.2) vs 3.6 (2.0-6.9), P=0.035], and higher proportion of patients with cutaneous eruption [42.9% vs 6.9%, P=0.015] than non-DED group. According to multiple-factor binary logistic regression analysis, the SLEDAI-2K score (OR=1.194, P=0.041) and cutaneous eruption (OR=7.094, P=0.045) could be consider as risk factors for DED in SLE patients. The ROC curve of the combined factors including age, disease duration, SLEDAI-2K score, ACL, and cutaneous eruption was analyzed, with a sensitivity of 0.786, a specificity of 0.793, and an area under curve of 0.820. CONCLUSION: Ocular surface affection is frequent in SLE patients, and patients with high disease activity and cutaneous eruption show increased risk of DED.

Environmental factors and host sex influence the skin microbiota structure of Hong Kong newt (Paramesotriton hongkongensis) in a coldspot of chytridiomycosis in subtropical East Asia.

Chytridiomycosis, an infectious skin disease caused by the chytrid fungi, Batrachochytrium dendrobatidis and B. salamandrivorans, poses a significant threat to amphibian biodiversity worldwide. Antifungal bacteria found on the skin of chytrid-resistant amphibians could potentially provide defense against chytridiomycosis and lower mortality rates among resistant individuals. The Hong Kong newt (Paramesotriton hongkongensis) is native to East Asia, a region suspected to be the origin of chytrids, and has exhibited asymptomatic infection, suggesting a long-term coexistence with the chytrids. Therefore, the skin microbiota of this resistant species warrant investigation, along with other factors that can affect the microbiota. Among the 149 newts sampled in their natural habitats in Hong Kong, China, putative antifungal bacteria were found in all individuals. There were 314 amplicon sequence variants distributed over 25 genera of putative antifungal bacteria; abundant ones included Acinetobacter, Flavobacterium, and Novosphingobium spp. The skin microbiota compositions were strongly influenced by the inter-site geographical distances. Despite inter-site differences, we identified some core skin microbes across sites that could be vital to P. hongkongensis. The dominant cores included the family Comamonadaceae, family Chitinophagaceae, and class Betaproteobacteria. Moreover, habitat elevation and host sex also exhibited significant effects on skin microbiota compositions. The antifungal bacteria found on these newts offer an important resource for conservation against chytridiomycosis, such as developing probiotic treatments for susceptible species.

Chromosome-scale Genome assembly of the critically endangered White-eared Night-Heron (Gorsachius magnificus).

The White-eared Night-Heron (Gorsachius magnificus, G. magnificus) is a critically endangered heron that is very poorly known and only found in southern China and northern Vietnam, with an estimated population of 250 to 999 mature individuals. However, the lack of a reference genome has hindered the implementation of conservation management efforts. In this study, we present the first high-quality chromosome-scale reference genome, which was assembled by integrating PacBio long-reads sequencing, Illumina paired-end sequencing, and Hi-C technology. The genome has a total length of 1.176 Gb, with a scaffold N50 of 84.77 Mb and a contig N50 of 18.46 Mb. Utilizing Hi-C data, we anchored 99.89% of the scaffold sequences onto 29 pairs of chromosomes. Additionally, we identified 18,062 protein-coding genes in the genome, with 95.00% of which were functionally annotated. Notably, BUSCO assessment confirmed the presence of 97.2% of highly conserved Aves genes within the genome. This chromosome-level genome assembly and annotation will be valuable for future investigating the G. magnificus's evolutionary adaptation and conservation.