The dynamic behavior of chromatophores marks the transition from bands to spots in leopard geckos

Proceedings of the National Academy of Sciences, Journal Year: 2024, Volume and Issue: 121(29)

Published: July 8, 2024

Reptilian skin coloration is spectacular and diverse, yet little known about the ontogenetic processes that govern its establishment molecular signaling pathways determine it. Here, we focus on development of banded pattern leopard gecko hatchlings transition to black spots in adult. With our histological analyses, show iridophores are present white yellow bands hatchling they gradually perish adult skin. Furthermore, demonstrate melanophores can autonomously form absence other chromatophores both regenerated tail dorsal Mack Super Snow (MSS) geckos. This color morph characterized by uniform adulthood; establish their devoid xanthophores at stages. Our genetic analyses identified a 13-nucleotide deletion PAX7 transcription factor MSS geckos, affecting protein coding sequence. single-cell transcriptomics analysis embryonic skin, confirm expressed xanthophores, suggesting it plays key role differentiation chromatophores. situ hybridizations whole-mount embryos document dynamics formation how impacted mutants. We hypothesize melanophores–iridophores interactions give rise spot an intrinsic capacity postembryonic

Language: Английский

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Dominant Negative Mitf Allele Impacts Melanophore and Xanthophore Development and Reveals Collaborative Interactions With Tfec in Zebrafish Chromatophore Lineages

Pigment Cell & Melanoma Research, Journal Year: 2025, Volume and Issue: 38(2)

Published: March 1, 2025

ABSTRACT Ectothermic vertebrates exhibit a diverse array of pigment cell types—chromatophores—that provide valuable opportunities to uncover mechanisms fate specification and how they evolve. Like melanocytes mammals, the melanophores teleosts other ectotherms depend on basic helix–loop–helix leucine zipper transcription factors encoded by orthologues MITF . A different chromatophore, iridescent iridophore, depends closely related factor Tfec. Requirements for chromatophore lineages remain largely uncertain. Here we identify new allele zebrafish Mitf gene, mitfa , that results in complete absence not only but also yellow‐orange xanthophores. Harboring missense substitution DNA‐binding domain identical previously isolated alleles mouse, show this has defects precursor survival xanthophore differentiation extend beyond those loss‐of‐function. Additional genetic analyses revealed interactions between Mitfa Tfec as likely basis observed phenotypes. Our findings point collaborative roles promoting development, particularly lineages, insights into evolutionary aspects functions across vertebrates.

Language: Английский

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Ultrastructural studies distinguish skin diversities among Galápagos iguanas

Biology Direct, Journal Year: 2025, Volume and Issue: 20(1)

Published: Feb. 4, 2025

Iguanas exhibit diverse colors and behaviors reflecting evolutionarily adaptation to various habitats; in particular, the Galápagos iguanas represent unique color morphologies with distinct ecological niches. While external coloration has implications, comprehensive studies on histological ultrastructural aspects of their skin can provide insight into extreme environments, such as high UV exposure. Starting from these considerations present study investigates histological, immunohistochemical features comprehensively characterize adults three species (A. cristatus, C. subcristatus marthae). Morphological analysis revealed significant differences among species, black-colored A. cristatus showing a melanin-rich but vessel-poor dermis, while marthae displayed varying distributions melanosomes melanocytes. Notably, absence iridophores was consistent across all samples due birefringent material under optical microscope. Morphometric evaluations highlighted interspecific stratum corneum thickness, particularly between black- non-black-colored (irrespectively if yellowish or pink) skin. The investigation confirmed analyzed samples. cytokeratin expression assessed by immunohistochemistry showed stratified epithelium epidermis (pink) presence thickened stratification non-pigmented could help pink iguana cope conditions Wolf volcano, especially relation These characteristics may reduce penetration power rays superficial loose thereby attenuating potential UV-related damage DNA breaks ROS generation. findings offer insights adaptive strategies iguanas.

Language: Английский

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GTP cyclohydrolase II (gch2) and axanthism in ball pythons: A new vertebrate model for pterin‐based pigmentation

Animal Genetics, Journal Year: 2025, Volume and Issue: 56(2)

Published: April 1, 2025

Abstract Pterin pigments are responsible for many of the bright colors observed across animal kingdom. However, unlike melanin, genetics pterin‐based pigmentation has received relatively little attention in coloration studies. Here, we investigate a lineage axanthic ball pythons ( Python regius ) found captivity as model system to study pterin vertebrates. By crowdsourcing shed skin samples from commercial breeders and applying case–control design, used whole‐genome pool sequencing (pool‐seq) variant annotation. We identified premature stop codon gene GTP cyclohydrolase II gch2 ), which is associated with phenotype. GCH2 catalyzes first rate‐limiting step riboflavin biosynthesis. This provides identification an axanthism‐associated vertebrates highlights utility pigmentation.

Language: Английский

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A genomic perspective on the origins, evolution and adaptation of Galápagos iguanas

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2025, Volume and Issue: unknown

Published: April 17, 2025

Abstract Island systems provide unique opportunities to explore the genomic basis of species diversification and novel trait evolution driven by adaptation environmental challenges exploitation new ecological niches. Here we generate first sequences for four Galápagos iguana show that they evolved in situ into marine Amblyrhynchus land Conolophus sister lineages on now submerged islands, following a single colonisation event approximately 13 million years ago, with evidence recent inbreeding coincident timing human settlement. Selection scans identified genes linked traits facilitating adaption environment, including specialised pigmentation phenotypes, as well DNA damage UV irradiation inflammation responses. These may contribute adaptive enhanced cancer resistance, relation elevated exposure at equatorial latitudes. In iguana, under positive selection are associated their transition underwater foraging, ability repeatedly shrink grow body size. Our study provides insights origins iguanas molecular life Galápagos, future conservation management threatened iguanid populations.

Language: Английский

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PMEL is involved in snake colour pattern transition from blotches to stripes

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: Sept. 3, 2024

Abstract Corn snakes are emerging models for animal colouration studies. Here, we focus on the Terrazzo morph, whose skin pattern is characterized by stripes rather than blotches. Using genome mapping, discover a disruptive mutation in coding region of Premelanosome protein ( PMEL ) gene. Our transcriptomic analyses reveal that expression significantly downregulated embryonic tissues. We produce corn snake knockouts, which present comparable phenotype to and subcellular structure their melanosomes xanthosomes also similarly impacted. single-cell wild-type dorsal demonstrate all chromatophore progenitors express at varying levels. Finally, show embryos -expressing cells initially uniformly spread before forming aggregates eventually blotches, as seen adults. In embryos, fail form. results provide insights into mechanisms governing patterning reptiles.

Language: Английский

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A Ball Python Colour Morph Implicates MC1R in Melanophore–Xanthophore Distribution and Pattern Formation

Pigment Cell & Melanoma Research, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 28, 2024

ABSTRACT Reptiles showcase an extensive array of skin colours and patterns, yet little is known about the genetics reptile colouration. Here, we investigate genetic basis Clown colour morph found in captive‐bred ball pythons ( Python regius ) to study pigmentation patterning snakes. We obtained samples by crowdsourcing shed from commercial breeders hobbyists. applied a case–control design, whole‐genome pool sequencing, variant annotation, histological analyses, electron microscopy imaging. identified missense mutation transmembrane region melanocortin‐1 receptor MC1R associated with phenotype. In classic avian mammalian model species, for controlling type amount melanin produced. contrast, our results suggest that signalling might play key role pattern formation pythons, affecting xanthophore–melanophore distribution. This work highlights varied functions across different vertebrate lineages promotes novel system

Language: Английский

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Skin Ultrastructural Analysis Reveals a Lack of Iridophores in Adult Individuals of Differently-Colored Species of Galápagos Iguanas

Published: May 20, 2024

Critically Endangered Galápagos pink land iguanas (Conolophus marthae) are one of the rarest species iguana, found exclusively on Isabela Island, in Galápagos. A previous histological study provided an explanation unique color adult C. marthae. Still, it also raised a question related to recent discovery that marthae hatchlings not upon emergence. Like subcristatus, another iguana species, they maculated, but contrary exhibit green pattern. Generally, greenish, and bluish colors reptiles primarily due interaction between different types chromatophores skin layers. Iridophores particularly important among chromophores, as contain guanine nanocrystals capable reflecting diffracting light. Green emerges when mostly diffracted blue wavelength interferes with carotenoids xanthophores. In multiapproach analysis, we investigated histological, ultrastructural immunohistochemical features differently-colored areas three iguanas. We tested for presence described characteristics stratus corneum, germinativum stratum laxum species. Results demonstrated absence iridophores adults regardless color, stratified epithelium non-black-colored skin. This research furthers interest evolutionary significance coloration The calls additional demonstrate document possible ontogenetic changes may lead lack adults. An investigation could take advantage genome mapping gene expression along developmental gradient would be greatly beneficial advancing understanding genomic basis and, general, reptile coloration.

Language: Английский

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GTP cyclohydrolase 1and axanthism in ball pythons: a new vertebrate model for pterin-based pigmentation

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: May 26, 2024

Abstract Pterin pigments are responsible for many of the bright colours observed across animal kingdom. However, unlike melanin, genetics pterin-based pigmentation has received relatively little attention in colouration studies. Here, we investigate a lineage axanthic ball pythons ( Python regius ) found captivity as model system to study pterin vertebrates. By crowdsourcing shed skin samples from commercial breeders and applying case-control design, utilized whole-genome pool sequencing (pool-seq) variant annotation. We identified premature stop codon gene GTP cyclohydrolase II gch2 ), which is associated with phenotype. GCH2 catalyzes first rate-limiting step riboflavin biosynthesis. This provides identification an axanthism-associated vertebrates highlights utility pigmentation.

Language: Английский

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