Sequence variation in the melanocortin-1 receptor (MC1R) pigmentation gene and its role in the cryptic coloration of two South American sand lizards

Abstract

In reptiles, dorsal body darkness often varies with substrate color or temperature environment, and is generally presumed to be an adaptation for crypsis or thermoregulation. However, the genetic basis of pigmentation is poorly known in this group. In this study we analyzed the coding region of the melanocortin-1-receptor (MC1R) gene, and therefore its role underlying the dorsal color variation in two sympatric species of sand lizards (Liolaemus) that inhabit the southeastern coast of South America: L. occipitalis and L. arambarensis. The first is light-colored and occupies aeolic pale sand dunes, while the second is brownish and lives in a darker sandy habitat. We sequenced 630 base pairs of MC1R in both species. In total, 12 nucleotide polymorphisms were observed, and four amino acid replacement sites, but none of them could be associated with a color pattern. Comparative analysis indicated that these taxa are monomorphic for amino acid sites that were previously identified as functionally important in other reptiles. Thus, our results indicate that MC1R is not involved in the pigmentation pattern observed in Liolaemus lizards. Therefore, structural differences in other genes, such as ASIP, or variation in regulatory regions of MC1R may be responsible for this variation. Alternatively, the phenotypic differences observed might be a consequence of non-genetic factors, such as thermoregulatory mechanisms.

Variability of the mc1r Gene in Melanic and Non-Melanic Podarcis lilfordi and Podarcis pityusensis from the Balearic Archipelago

“…Although the same gene contributes to light phenotypes in these White Sands populations, the specific molecular mechanisms leading to reduced melanism production appear to be different. In contrast, sequence variation in mc1r does not explain melanism in the widespread amphibian Rana temporaria [10] nor does it appear to be involved in dorsal colour adaptations in two sympatric species of sand lizard ( Liolaemus ) that inhabit the south eastern coast of South America [11] or colour pattern in Uta lizards [12]. Some authors consider blue colouration to be a form of melanism in reptiles [13].…”

Genetic Bases Of Aposematic Traits: Insights from the Skin Transcriptional Profiles of Oophaga Poison Frogs

“…Thus, it is possible that structural or expression differences in the MC1R might contribute to dark phenotypes in Oophaga frogs. While there is a strong evidence that different mutations at MC1R cause either light or dark phenotypes in many mammals, birds and reptiles [84–88], the only two studies conducted in frogs are inconclusive [89, 90]. A detailed inspection of the coding sequences recovered for this gene revealed the presence of different length isoforms, making MC1R a promising candidate gene candidate to explain the differences in background coloration in poison frogs [15].…”

Bio‐Inspired Photonic Materials: Prototypes and Structural Effect Designs for Applications in Solar Energy Manipulation

“…These micro/nanostructured natural creatures have been optimized, to display the coloration most adapted to the various needs and purposes of living creatures. Structural colorations have various biological functions, such as conspicuousness (e.g., increase reflection, warning, or attractant to conspecifics), camouflage, signaling, thermoregulation, and so forth . For example, insect's compound eye with hundreds of non‐close‐packed nanonipples covering the hexagonally close‐packed micro‐ommatidia on spherical macro‐bases is a typical prototype of antireflection (AR) and wide field‐of‐view ( Figure B(a,b)) .…”

“…Reproduced with permission. [2c] Copyright 2014, Wiley‐VCH. (d) A digital camera inspired by compound eyes.…”

“…Reproduced with permission. [2d] Copyright 2013, Nature Publishing Group. C) Broadband reflection in the visible region.…”