CPR Gene Contributes to Integument Function and Ovary Development in a Rice Planthopper.

Nicotinamide adenine dinucleotide phosphate (NADPH)-cytochrome P450 reductase (CPR) is an essential enzyme that transfers electrons from NADPH to cytochrome P450 monooxygenases. CPR is involved in cuticular hydrocarbon (CHC) synthesis in insects and is vital for insect development and survival. Here, we clarify the physiological function of a CPR gene in Nilaparvata lugens, an important rice pest, by using RNA interference. CPR gene knockdown leads to the functional loss of waterproofing and water retention in the integument of female adults, which causes significantly reduced body weight and a lethal phenotype. Scanning electron microscopy shows that the lipid layer on the outermost surface of the abdominal cuticle becomes thin in dsCPR-injected adults. Furthermore, CHC profile analysis reveals that CPR knockdown significantly decreases the contents of CHCs with a carbon chain length ≥ C27 in adult females. Moreover, we find that CPR knockdown generates a deficient phenotype in ovaries with deformed oocytes and a complete failure of egg-laying. These findings suggest that CPR plays multiple functional roles in CHC biosynthesis and embryo development in insects.

A CYP380C10 gene is required for waterproofing and water retention in the insect integument.

Cuticular hydrocarbons (CHCs) are important components in the integument of insects and are required for development and survival. Insect-specific CYP4G subfamily, of the P450 enzymes, catalyze the oxidative decarbonylation step in the biosynthesis of CHCs. Here, we characterized CYP380C10 gene function in a Hemiptera rice pest, Nilaparvata lugens. We used RNA interference-mediated expression silencing to reveal that NlCYP380C10 played a key role in waterproofing and water-retention in the integument of N. lugens. Knockdown of NlCYP380C10 significantly reduced body weight and caused mortality. Scanning electron microscopy showed the loss of the lipid layer on the surface of the abdominal cuticle of the dsNlCYP380C10-injected adults. Furthermore, CHC profile analysis revealed that NlCYP380C10 knockdown significantly decreased the amounts of CHCs in adult females. This suggested that NlCYP380C10 was involved in CHC biosynthesis. Reduction of CHC content caused the loss of the intact lipid layer of the cuticle, which resulted in loss of the waterproofing and water-retention functions. This led to failure of molting and eclosion. Our findings expanded the knowledge of CHC biosynthesis in the insect integument and led to a better understanding of the functional roles of CYP450 genes involved in waterproofing and water-retention in insects.

Melanin synthesis genes BgTH and BgDdc affect body color and cuticle permeability in Blattella germanica.

Melanin is involved in cuticle pigmentation and sclerotization of insects, which is critical for maintaining structural integrity and functional completeness of insect cuticle. The 2 key enzymes of tyrosine hydroxylase (TH) and dopa decarboxylase (DDC) predicted in melanin biosynthesis are usually conserved in insects. However, it is unclear whether their function is related to epidermal permeability. In this study, we identified and cloned the gene sequences of BgTH and BgDdc from Blattella germanica, and revealed that they both showed a high expression at the molting, and BgTH was abundant in the head and integument while BgDdc was expressed highest in the fat body. Using RNA interference (RNAi), we found that knockdown of BgTH caused molting obstacles in some cockroaches, with the survivors showing pale color and softer integuments, while knockdown of BgDdc was viable and generated an abnormal light brown body color. Desiccation assay showed that the dsBgTH-injected adults died earlier than control groups under a dry atmosphere, but dsBgDdc-injected cockroaches did not. In contrast, when dsRNA-treated cockroaches were reared under a high humidity condition, almost no cockroaches died in all treatments. Furthermore, with eosin Y staining assay, we found that BgTH-RNAi resulted in a higher cuticular permeability, and BgDdc-RNAi also caused slight dye penetration. These results demonstrate that BgTH and BgDdc function in body pigmentation and affect the waterproofing ability of the cuticle, and the reduction of cuticular permeability may be achieved through cuticle melanization.

A new Early Cretaceous lizard in Myanmar amber with exceptionally preserved integument.

We here report on a well-preserved juvenile lizard specimen in Albian amber (ca. 110 mya) from the Hkamti site (Myanmar). This new taxon is represented by an articulated skull and the anterior portion of the trunk, including the pectoral girdle and forelimbs. The scleral ossicles and eyelid are also visible, and the specimen exhibits pristine detail of the integument (of both head and body). In a combined molecular and morphological analysis, it was consistently recovered as a scincoid lizard (Scinciformata), as sister to Tepexisaurus + Xantusiidae. However, the phylogenetic position of the new taxon should be interpreted with caution as the holotype is an immature individual. We explored the possibility of miscoding ontogenetically variable characters by running alternative analyses in which these characters were scored as missing data for our taxon. With the exception of one tree, in which it was sister to Amphisbaenia, the specimen was recovered as a Pan-xantusiid. Moreover, we cannot rule out the possibility that it represents a separate lineage of uncertain phylogenetic position, as it is the case for many Jurassic and Cretaceous taxa. Nonetheless, this fossil offers a rare opportunity to glimpse the external appearance of one group of lizards during the Early Cretaceous.

Comparison of vertebrate skin structure at class level: A review.

The skin is a barrier between the internal and external environment of an organism. Depending on the species, it participates in multiple functions. The skin is the organ that holds the body together, covers and protects it, and provides communication with its environment. It is also the body's primary line of defense, especially for anamniotes. All vertebrates have multilayered skin composed of three main layers: the epidermis, the dermis, and the hypodermis. The vital mission of the integument in aquatic vertebrates is mucus secretion. Cornification began in apmhibians, improved in reptilians, and endured in avian and mammalian epidermis. The feather, the most ostentatious and functional structure of avian skin, evolved in the Mesozoic period. After the extinction of the dinosaurs, birds continued to diversify, followed by the enlargement, expansion, and diversification of mammals, which brings us to the most complicated skin organization of mammals with differing glands, cells, physiological pathways, and the evolution of hair. Throughout these radical changes, some features were preserved among classes such as basic dermal structure, pigment cell types, basic coloration genetics, and similar sensory features, which enable us to track the evolutionary path. The structural and physiological properties of the skin in all classes of vertebrates are presented. The purpose of this review is to go all the way back to the agnathans and follow the path step by step up to mammals to provide a comparative large and updated survey about vertebrate skin in terms of morphology, physiology, genetics, ecology, and immunology.

Drenaje percutáneo ecoguiado vs. drenaje quirúrgico en abscesos cervicales profundos de origen odontógeno. Ensayo clínico controlado y aleatorizado / Ultrasound-guided drainage vs surgical drainage of deep neck space abscesses: A randomized controlled trial

Introducción: La causa más frecuente de infecciones profundas del cuello son las infecciones odontógenas. Son diagnosticadas con examen físico, estudios por imágenes, ecografía o tomografía computarizada. Debe realizarse siempre el drenaje quirúrgico de forma clásica o percutánea según el caso de las colecciones en forma precoz. El objetivo fue comparar las técnicas de drenaje percutáneo guiado por ecografía vs. drenaje quirúrgico en abscesos cervicales profundos de origen odontógeno en forma controlada y aleatorizada. Métodos: Se realizó un ensayo clínico controlado aleatorizado de enero de 2015 a diciembre de 2019. Se evaluó como variable de eficacia los días de ingreso. Se analizaron los datos epidemiológicos y variables secundarias (tumoración, trismus, fiebre, dolor), leucocitosis, resultado cosmético comparando ambas técnicas. El análisis estadístico se llevó a cabo con STATA v 14.0. Resultados: Fueron analizados 128 pacientes, 51 mujeres y 77 hombres. Edad promedio 27,3 (SD = 10,13). El grupo percutáneo presentó una media de 3,03 (SD = 2,86) días de ingreso y el grupo quirúrgico 5,46 (SD = 2,96). El valor de p resultó <0,001. Los resultados cosméticos mostraron diferencias favor del grupo de drenaje percutáneo. Ninguna de las demás variables mostró resultados estadísticamente significativos. Discusión: Ante la evidencia de una colección extensa en espacios profundos la realización del tratamiento quirúrgico (cervicotomía y desbridamiento) debe hacerse en forma precoz. Los procedimientos mínimamente invasivos guiados por imágenes son una alternativa. Estos pueden realizarse en colecciones bien localizadas, uniloculares, y siempre que no exista compromiso de la vía aérea del paciente. Pueden realizarse técnicas de punción y aspiración, y si es necesario en forma seriada, o bien punción con colocación de drenajes. (AU)

Introduction: The most common cause of deep neck infections is dental infection. They are diagnosed with physical examination, imaging studies, ultrasound, or computed tomography. Surgical drainage of collections should always be performed early in a classical or percutaneous way, depending on the case. The aim of the study was to compare ultrasound-guided percutaneous drainage techniques vs. surgical drainage in deep cervical abscesses of odontogenic origin in a controlled and randomized trial. Methods: A randomized controlled clinical trial was performed from January 2015 to December 2019. Hospital stay was evaluated as an efficiency variable. Epidemiological and secondary variable data (tumour, trismus, fever, pain), leukocytosis, cosmetic result comparing both techniques were analysed. Statistical analysis was carried out with STATA v 14.0. Results: 128 patients were analysed, 51 women and 77 men. Average age 27.3 (SD = 10.13). The percutaneous group had a mean hospital stay of 3.03 (SD = 2.86) days and the surgical group 5.46 (SD = 2.96). The p-value was <.001. Cosmetic results showed differences favouring the percutaneous drainage group. None of the other variables showed statistically significant results. Discussion: Surgical treatment (cervicotomy and debridement) should be undertaken early with evidence of extensive collection in deep spaces. Minimally invasive image-guided procedures are an alternative. These can be performed in well-located, unilocular collections, without compromising of the patient's airway. Percutaneous drainage and suction techniques if necessary, serially, or drainage placement may be performed. (AU)

Two putative fatty acid synthetic genes of BgFas3 and BgElo1 are responsible for respiratory waterproofing in Blattella germanica.

Water retention is critical for physiological homeostasis and survival in terrestrial insects. While deposition of hydrocarbons on insect cuticles as a key measure for water conservation has been extensively investigated, we know little about other mechanisms for preventing water loss in insects. Here, we report two fatty acid synthetic genes that are independent of hydrocarbon production but crucial for water retention in the German cockroach Blattella germanica (L.). First, an integument enriched fatty acid elongase gene (BgElo1) was identified as a critical gene for desiccation resistance in B. germanica; however, knockdown of BgElo1 surprisingly failed to cause a decline in cuticular lipids. In addition, RNA interference (RNAi)-knockdown of an upstream fatty acid synthase gene (BgFas3) showed a similar phenotype, and transmission electron microscopy analysis revealed that BgFas3- or BgElo1-RNAi did not affect cuticle architecture. Bodyweight loss test showed that repression of BgFas3 and BgElo1 significantly increased the weight loss rate, but the difference disappeared when the respiration was closed by freeze killing the cockroaches. A water immersion test was performed, and we found that BgFas3- and BgElo1-RNAi made it difficult for cockroaches to recover from drowning, which was supported by the upregulation of hypoxia-related genes after a 10-h recovery from drowning. Moreover, a dyeing assay with water-soluble Eosin Y showed that this was caused by the entry of water into the respiratory system. Our research suggests that BgFas3 and BgElo1 are required for both inward and outward waterproofing of the respiratory system. This study benefits the understanding of water retention mechanisms in insects.

The bioactive compound carvacrol as a potential acaricide: An assessment of its effects on the integument of female Rhipicephalus sanguineus sensu lato ticks.

Studies seeking control methods for infestation of Riphicephalus sanguineus sensu lato (s.l.) ticks (dog ticks) have been carried out in order to minimize damage to both the tick's hosts and the environment, the latter due to the misuse of acaricide products. In this regard, carvacrol has been used as a natural alternative against ticks as it displays several properties including acaricidal. In this context, the present study aimed to evaluate the ultramorphology and morphohistochemistry of the integument of semi-engorged R. sanguineus s.l. females exposed to different carvacrol concentrations. The findings indicate that the integument surface of females exposed to the highest carvacrol concentration (25 µl/ml) became wrinkled, suggesting dehydration or the result of integument cuticular and epithelial layer disorganization in response to the toxic product. Morphohistochemical integument layer alterations were more significant and intense in females exposed to the highest carvacrol concentration (25 µl/ml), confirming dose-dependent carvacrol action. Among other cell and tissue alterations, changes in epithelial cell shape, size, and arrangement (epidermal layer) were noted, alongside altered and pyknotic-shaped nuclei, suggesting a death process for these cells. This epithelium changed from simple cubic to stratified, also in response to the presence of the evaluated bioactive compound. Thus, the findings reported herein demonstrate that carvacrol may be an alternative for an efficient and more sustainable tick control in the near future.

Learning media based on augmented reality (AR) increased the skill of physical examination of the integumentary system of pregnant women in midwifery students.

OBJECTIVE: This research was to analyze the correlation of AR-based Learning Media to improving the physical examination of the integumentary system of pregnant women in midwifery students. METHOD: The research method used Quasi-experimental with Non-Equivalent Control Group Design. The sample of 92 students was selected by a purposive sample, divided into two intervention and control groups. The intervention group was 62 students, and the control group was 30 students. Data collection was performed using a checklist to assess the skill of the physical examination of the integumentary system of pregnant women. To test the differences of skill before and after treatment in control and intervention groups used the Mcnemar test, whereas to know the differences in skill from time to time Cochran test was used. RESULT: The results showed differences in the measurement of skills improvement in the control and intervention groups before and after the intervention was given. A more significant increase in skills occurred in the intervention group with a p-value <0.001 contributing after 1week of giving a demonstration, and application-based (AR) skills increased by 66.1%. After two weeks it increased by 93.5%, and after two weeks it increased by 100%. So it could be concluded statistically that AR-based learning media was significant in improving the physical examination skills integumentary systems in pregnant women.

Effect of Lonomia obliqua Venom on Human Neutrophils.

The significant incidence of deforestation in South America culminates in the contact of humans with typical forests species. Among these species, one may highlight Lonomia obliqua caterpillar, which, when touched by humans, can poison them through their bristles. Therefore, better acknowledging the mechanisms involved in envenomation caused by Lonomia obliqua caterpillar bristle extract (LOCBE) may contribute to further treatments. Recently, we demonstrated that LOCBE induces a pro-inflammatory profile in endothelial cells; thus, we decided to investigate the effects of LOCBE on human polymorphonuclear neutrophils (PMN), which are the first leukocytes that migrate to the inflammatory focus. Our results showed that treatment with LOCBE induced PMN chemotaxis together with alterations in actin cytoskeleton and focal adhesion kinase (FAK) activation, favoring migration. Concurrently, LOCBE induced PMN adhesion to matrix proteins, such as collagen IV, fibronectin, and fibrinogen. Moreover, we observed that LOCBE attenuated PMN apoptosis and increased reactive oxygen species (ROS) production together with nuclear factor kB (NF-κB) activation-a redox-sensitive transcription factor-as well as interleukin (IL)-1ß and IL-8 release. We call attention to the ROS-dependent effect of LOCBE on increased cell migration once an antioxidant treatment reverted it. In summary, we report that LOCBE activates PMN, inducing pro-inflammatory responses modulated by ROS.

Chromatin accessibility profiling provides insights into larval cuticle color and adult longevity in butterflies.

Butterflies are diverse in virtually all aspects of their ontogeny, including morphology, life history, and behavior. However, the developmental regulatory mechanisms underlying the important phenotypic traits of butterflies at different developmental stages remain unknown. Here, we investigated the developmental regulatory profiles of butterflies based on transposase accessible chromatin sequencing (ATAC-seq) at three developmental stages in two representative species ( Papilio xuthus and Kallima inachus). Results indicated that 15%-47% of open chromatin peaks appeared in associated genes located 3 kb upstream (i.e., promoter region) of their transcription start site (TSS). Comparative analysis of the different developmental stages indicated that chromatin accessibility is a dynamic process and associated genes with differentially accessible (DA) peaks show functions corresponding to their phenotypic traits. Interestingly, the black color pattern in P. xuthus 4th instar larvae may be attributed to promoter peak-related genes involved in the melanogenesis pathway. Furthermore, many longevity genes in 5th instar larvae and pupae showed open peaks 3 kb upstream of their TSS, which may contribute to the overwintering diapause observed in K. inachus adults. Combined with RNA-seq analysis, our data demonstrated that several genes enriched in the melanogenesis and longevity pathways also exhibit higher expression, confirming that the expression of genes may be closely related to their phenotypic traits. This study offers new insights into larval cuticle color and adult longevity in butterflies and provides a resource for investigating the developmental regulatory mechanisms underlying butterfly ontogeny.

Bumble bee queen pheromones are context-dependent.

Queen pheromones have long been studied as a major factor regulating reproductive division of labor in social insects. Hitherto, only a handful of queen pheromones were identified and their effects on workers have mostly been studied in isolation from the social context in which they operate. Our study examined the importance of behavioral and social context for the perception of queen semiochemicals by bumble bee workers. Our results indicate that a mature queen's cuticular semiochemicals are capable of inhibiting worker reproduction only when accompanied by the queen's visual presence and the offspring she produces, thus, when presented in realistic context. Queen's chemistry, queen's visual presence and presence of offspring all act to regulate worker reproduction, but none of these elements produces an inhibitory effect on its own. Our findings highlight the necessity to reconsider what constitutes a queen pheromone and suggest a new approach to the study of chemical ecology in social insects.

Regional Specific Differentiation of Integumentary Organs: Regulation of Gene Clusters within the Avian Epidermal Differentiation Complex and Impacts of SATB2 Overexpression.

The epidermal differentiation complex (EDC) encodes a group of unique proteins expressed in late epidermal differentiation. The EDC gave integuments new physicochemical properties and is critical in evolution. Recently, we showed ß-keratins, members of the EDC, undergo gene cluster switching with overexpression of SATB2 (Special AT-rich binding protein-2), considered a chromatin regulator. We wondered whether this unique regulatory mechanism is specific to ß-keratins or may be derived from and common to EDC members. Here we explore (1) the systematic expression patterns of non-ß-keratin EDC genes and their preferential expression in different skin appendages during development, (2) whether the expression of non-ß-keratin EDC sub-clusters are also regulated in clusters by SATB2. We analyzed bulk RNA-seq and ChIP-seq data and also evaluated the disrupted expression patterns caused by overexpressing SATB2. The results show that the expression of whole EDDA and EDQM sub-clusters are possibly mediated by enhancers in E14-feathers. Overexpressing SATB2 down-regulates the enriched EDCRP sub-cluster in feathers and the EDCH sub-cluster in beaks. These results reveal the potential of complex epigenetic regulation activities within the avian EDC, implying transcriptional regulation of EDC members acting at the gene and/or gene cluster level in a temporal and skin regional-specific fashion, which may contribute to the evolution of diverse avian integuments.

Segmentation of the subcuticular fat body in Apis mellifera females with different reproductive potentials.

Evolution has created different castes of females in eusocial haplodiploids. The difference between them lies in their functions and vulnerability but above all in their reproductive potentials. Honeybee queens are highly fertile. On the other hand, the workers are facultatively sterile. However, rebel workers, i.e. workers that develop in a queenless colony, reproduce more often than normal workers. As a result, the fat body of these bees, which apart from acting as the energy reserve, is also the site of numerous metabolic processes, had to specialize in different functions perfected over millions of years of eusocial evolution. Assuming that the variety of functions manifests itself in the pleomorphic structure of the fat body cells, we predicted that also different parts of the fat body, e.g. from different segments of the abdomen, contain different sets of cells. Such differences could be expected between queens, rebels and normal workers, i.e. females with dramatically different reproductive potentials. We confirmed all these expectations. Although all bees had the same types of cells, their proportion and segmental character corresponded with the caste reproductive potential and physiological characteristics shaped in the evolutionary process. The females with an increased reproductive potential were characterized by the presence of oenocytes in the third tergite and high concentrations of compounds responsible for energy reserves, like glucose, glycogen and triglycerides. Queens had very large trophocytes, especially in the third tergite. Only in workers did we observe intercellular spaces in all the segments of the fat body, as well as high protein concentrations-especially in the sternite. As expected, the rebels combined many features of the queens and normal workers, what with other findings can help understand the ways that led to the origin of different castes in females of eusocial Hymenoptera.

The integumentary system and its microbiota between health and disease.

The aim of the present investigation was to evaluate the essential physiological functions of the skin microbiota in human health and diseases. The main characteristics of the normal microbiota in the different anatomical sites have been reported in relation to the main factors, such as the effect of age, on its composition and stability for the eubiosis condition. Moreover, the present overview analyzed the functions and composition and the correct functionality of the skin microbiota in the light of current knowledge. According to several evidence is important preserving the eubiosis of the commensal microbes of the microecosystem (symbiotic and pathogenic), and probiotics are able to counteract the conditions of dysbiosis. Also, it has been shown that there is a crosstalk between gut and skin microbiota that affects human health and is still being studied, and its relationship to the current pandemic SARS-CoV-2.

Evolutionary history of mental glands in turtles reveals a single origin in an aquatic ancestor and recurrent losses independent of macrohabitat.

Despite the relevance of chemical communication in vertebrates, comparative examinations of macroevolutionary trends in chemical signaling systems are scarce. Many turtle and tortoise species are reliant on chemical signals to communicate in aquatic and terrestrial macrohabitats, and many of these species possess specialized integumentary organs, termed mental glands (MGs), involved in the production of chemosignals. We inferred the evolutionary history of MGs and tested the impact of macrohabitat on their evolution. Inference of ancestral states along a time-calibrated phylogeny revealed a single origin in the ancestor of the subclade Testudinoidea. Thus, MGs represent homologous structures in all descending lineages. We also inferred multiple independent losses of MGs in both terrestrial and aquatic clades. Although MGs first appeared in an aquatic turtle (the testudinoid ancestor), macrohabitat seems to have had little effect on MG presence or absence in descendants. Instead, we find clade-specific evolutionary trends, with some clades showing increased gland size and morphological complexity, whereas others exhibiting reduction or MG loss. In sister clades inhabiting similar ecological niches, contrasting patterns (loss vs. maintenance) may occur. We conclude that the multiple losses of MGs in turtle clades have not been influenced by macrohabitat and that other factors have affected MG evolution.

How to Wear a Sandy Coat: Secretory Cells in the Dorsal Epidermis in the Sea Cucumber Holothuria atra (Echinodermata: Holothuroidea).

Holothuria atra is a black sea cucumber commonly found on the sandy bottom of Okinawan coral reefs. The body surface of H. atra is usually covered with sand; however, sand never covers the body of another black congener, Holothuria leucospilota, which is sympatrically distributed with H. atra. The epidermal structures were examined in these two species by means of transmission electron microscopy to determine how sand adheres to the surface of H. atra. While the epidermis was basically composed of support cells bearing microvilli and vacuolated cells probably corresponding to mucus cells, two types of granular cells, type 1 and 2, were also found at the tip of the tube feet. These granular cells were closely similar in structure to secretory cells that have been supposed to secrete adhesive substances in other holothurians. Type 1 granular cells were also found in the dorsal epidermis of H. atra but not in H. leucospilota. Therefore, adhesive secretion by type 1 granular cells probably enables the attachment of sand to the H. atra body.

Mesozoic cupules and the origin of the angiosperm second integument.

The second integument of the angiosperm ovule is unique among seed plants, with developmental genetics that are distinct from those of the inner integument1. Understanding how the second integument should be compared to structures in other seed plants is therefore crucial to resolving the long-standing question of the origin of angiosperms2-6. Attention has focused on several extinct plants with recurved cupules that are reminiscent of the anatropous organization of the basic bitegmic ovules of angiosperms1-6, but interpretations have been hampered by inadequate information on the relevant fossils. Here we describe abundant exceptionally well-preserved recurved cupules from a newly discovered silicified peat dating to the Early Cretaceous epoch (around 125.6 million years ago) in Inner Mongolia, China. The new material, combined with re-examination of potentially related fossils, indicates that the recurved cupules of several groups of Mesozoic plants are all fundamentally comparable, and that their structure is consistent with the recurved form and development of the second integument in the bitegmic anatropous ovules of angiosperms. Recognition of these angiosperm relatives (angiophytes) provides a partial answer to the question of angiosperm origins, will help to focus future work on seed plant phylogenetics and has important implications for ideas on the origin of the angiosperm carpel.

Making region-specific integumentary organs in birds: evolution and modifications.

Birds are the most diversified terrestrial vertebrates due to highly diverse integumentary organs that enable robust adaptability to various eco-spaces. Here we show that this complexity is built upon multi-level regional specifications. Across-the-body (macro-) specification includes the evolution of beaks and feathers as new integumentary organs that are formed with regional specificity. Within-an-organ (micro-) specification involves further modifications of organ shapes. We review recent progress in elucidating the molecular mechanisms underlying feather diversification as an example. (1) ß-Keratin gene clusters are regulated by typical enhancers or high order chromatin looping to achieve macro- and micro-level regional specification, respectively. (2) Multi-level symmetry-breaking of feather branches confers new functional forms. (3) Complex color patterns are produced by combinations of macro-patterning and micro-patterning processes. The integration of these findings provides new insights toward the principle of making a robustly adaptive bio-interface.

Genome-wide signatures of mammalian skin covering evolution.

Animal body coverings provide protection and allow for adaptation to environmental pressures such as heat, ultraviolet radiation, water loss, and mechanical forces. Here, using a comparative genomics analysis of 39 mammal species spanning three skin covering types (hairless, scaly and spiny), we found some genes (e.g., UVRAG, POLH, and XPC) involved in skin inflammation, skin innate immunity, and ultraviolet radiation damage repair were under selection in hairless ocean mammals (e.g., whales and manatees). These signatures might be associated with a high risk of skin diseases from pathogens and ultraviolet radiation. Moreover, the genomes from three spiny mammal species shared convergent genomic regions (EPHB2, EPHA4, and NIN) and unique positively selected genes (FZD6, INVS, and CDC42) involved in skin cell polarity, which might be related to the development of spines. In scaly mammals, the shared convergent genomic regions (e.g., FREM2) were associated with the integrity of the skin epithelium and epidermal adhesion. This study identifies potential convergent genomic features among distantly related mammals with the same skin covering type.