DOCSLIB.ORG

Iridescent Color: from Nature to the Painter's Palette

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Iridescent Color: from Nature to the Painter's Palette Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/LEON_a_00114 by guest on 25 September 2021 Technical ar T i c l e ce, Tech N e Iridescent Color: From Nature I , Sc to the Painter’s Palette T a b s T r a c T o: Ar nan The shifting rainbow hues of Franziska Schenk iridescence have, until recently, remained exclusive to nature. and Andrew Parker Now, the latest advances in nanotechnology enable the introduction of novel, bio- inspired color-shifting flakes into painting—thereby affording artists potential access to the full spectacle of iridescence. Unfortunately, existing rules rtists have never captured a color as dazzling selves of two distinct types: those of easel painting do not apply A that are stable attributes of material to the new medium; but, as and dynamic as the metallic blue of the Morpho butterfly, which nature inspired the technol- is visible for up to a quarter of a mile. Now, with rapid ad- substances, and those that are “acci- dental,” such as the evanescent col- ogy, an exploration of natural vances in nanoscience and technology, we are beginning to ors of the rainbow and the colors of phenomena can best inform unravel nature’s ingenious manipulation of the flow of light. some birds’ feathers, which change how to overcome this hurdle. Scientific research into natural nanoscale architectures, ca- according to the viewpoint of the Thus, by adopting a biomimetic pable of producing eye-catching optical effects, has led to the spectator [2]. approach, this paper outlines the optical principles underly- development of an ever-expanding range of comparable syn- ing iridescence and provides thetic structures. Particularly notable are the latest iridescent The “stable” colors, associated technical ground rules for its flakes. Although industry has exploited the novel properties with chemical pigments, have pre- incorporation into painting. of these flakes for almost a decade, fine-art painting has been occupied painters for millennia. slower to assimilate them. The major apparent hindrance is The rainbow, by contrast, remained the incompatibility with—and resulting confusion caused by mysterious until the 17th century, the material’s non-adherence to—color theory as applied in when Newton famously united light and color through his painting. Iridescent flakes, in themselves colorless, are “opti- prism experiment that proved white light consists of all the cal devices”—entirely different from the chemical pigments colors of the spectrum. The changeable hues of bird feathers traditionally found in paint. Consequently their application kept their secrets much longer. It was only in the mid-20th presents major challenges for artists. However, since the flakes century that science verified what the ancients had intuitively mimic nature’s technology, systematic analysis of the mecha- believed: that the colors of the rainbow and iridescence (a nisms that cause iridescent effects in animals can inspire analo- term evoking Iris, personification of the rainbow) are inextri- gous artistic methods. We can therefore establish, via studying cably linked. Both phenomena are caused by light interacting nature, some ground rules for adapting color-variable technol- with transparent, colorless matter. A rainbow is created when ogy to fine art painting. water droplets, like Newton’s prism, split white light into its As demonstrated by Schenk [1], the latest iridescent tech- components—the colors of the spectrum. Newton concluded nology offers manifold innovative artistic possibilities, together that the angle-dependent colors of birds’ feathers must equally with a unique potential aesthetics. result from light splitters (i.e. thin films) but did not compre- hend the precise color-producing mechanism [3]. In the 1950s electron microscopy, enabling nanoscale observations, finally wo isTincTly ifferenT ypes of olor T D D T c ascertained that iridescence in hummingbirds, for example, Gage’s Color in Art opens insightfully: is indeed produced by what effectively equates to a stack of thin films [4]. Here spectral colors are made visible via the Any European account of color in art must begin with the be- optical phenomenon of constructive interference, resulting lief, which dominated Western culture for many centuries, that light and color are distinct entities, and that colors are them- in color that changes with the direction of illumination and viewing angle. In the last decade, alternative iridescence-inducing ar- chitectures have been discovered in animals, and initial Franziska Schenk (artist, educator, researcher), Bournville Centre for Visual Arts, attempts to replicate them have been made by manufactur- Birmingham City University, Linden Road, Bournville, Birmingham, B30 1JX, U.K. ers [5,6]. Thin-film interference is the most common form E-mail: <[email protected]>. URL: <http://www.biosciences.bham.ac.uk/ artists_in_residence/>. of iridescence in nature and currently prevails in industry. Andrew Parker (research leader), Department of Zoology, The Natural History Museum, This optical phenomenon is, therefore, the focus of the Cromwell Road, London, SW7 5BD, U.K. E-mail: <[email protected]>. URL: <www.gtc. article. ox.ac.uk/andrew-parker>. Nature has retained a “monopoly on this metallic-like, col- This paper is presented as part of the Leonardo special section Nanotechnology, Nanoscale Science and Art, guest edited by Tami I. Spector. ored effect” [7]. Artistic attempts to capture iridescence have See <www.mitpressjournals.org/toc/leon/44/2> for supplemental files related to this been thwarted by restricted materials that appear much too article. dull in comparison. Chemical pigments absorb particular wave- lengths of incoming white light. The color impression, the re- article Frontispiece. cuttlefish, iridescent medium on board, a4 maining part of the light, changes neither hue nor brightness, size, 2007. (© F. schenk) even when viewed from different angles. Moreover, the color ©2011 ISAST LEONARDO, Vol. 44, No. 2, pp. 108–115, 2011 109 Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/LEON_a_00114 by guest on 25 September 2021 ech T temporary painters still operate within the confines of subtractive color theory, ce, Fig. 1. achieving silver-white. N derived from practical experience with e (a) chaotic layers, each tuned to I c a color of the spectrum. absorption pigments. Here the primaries S , (b) Three stacks, each tuned to T are red, yellow and blue. A mixture of a primary color. (© a. Parker) these colors becomes darker with each o: Ar primary added until black results, in an N complete reversal to what occurs in “sil- ver” fish. Natural iridescence adheres to the rules of additive/light mixture, based on the primaries red, green and blue, and so does iridescent “pigment.” Con- sequently, for iridescence ever to become a fixture on the painter’s palette, addi- tive and subtractive methods have to be mixed—a concept alien to artists. fades over time. Centuries of practical ex- [10]. In the centuries that followed, his In nature, on the other hand, chemical perience with absorption pigments have technique of grinding up the scales of pigments and structural colors are often led to firm rules for colorant mixing. silver fish such as bleak and herring re- combined. The composition of cuttlefish With the recent arrival of an altogether mained the only way of obtaining pearl skin is a prime example, its individually different type of “pigment” that imitates luster effects. adjustable color cells being arranged in natural thin-film structures, it is instruc- layers (Article Frontispiece). A bottom tive to re-examine certain doctrines. subtractive versus additive layer of silver “mirror” cells reflects colors Fueled by rapid advancements in na- color Theory from the surroundings. The cells above, noscience and manufacturing, the evolu- How can silver coloration in fish be ex- containing chemical pigments, switch tion of iridescent “pigment” technology plained? While the color appears identi- on (expand) and switch off (contract) is gaining momentum. While offering cal to that of the precious metal, no silver accordingly, thus (in combination with both non-toxic and fade-resistant prop- traces are found in fish scales/skin. The the “mirror” cells) assuming any color erties, the ever-expanding flake choices metallic color results from transparent desired via optical mixing. Studying such are most notable for their outstanding multi-layered architectures, known as color mechanisms can be instructive to purity, brilliance and innovative optics. broadband reflectors [11]. In a variation the painter. These qualities have enticed those in the of the thin-film formula, a number of lay- auto, cosmetics and plastics industries. ers of varying thickness are stacked (Fig. a First Generation Unfortunately the technology seems to 1a). Each layer reflects a different wave- of Pearlescent Flakes have bypassed fine art painting. The art length/color of the spectrum, depend- From the 1920s onward, sustained field’s lack of awareness of the medium’s ing on its particular optical thickness. attempts were made by industry to potentials is due, in part, to difficulties One layer reflects red; another slightly replicate natural pearl essence with a syn- in sourcing the product. Although paints thinner layer reflects orange; an even thetic alternative, because natural pearl based on first-generation flakes can now thinner one, yellow; then green, then essence is costly and limited in supply. be bought from specialist art suppliers, blue, etc., until all the colors of the rain- This eventually led to the conception of recent industrial color-variable flakes bow are reflected and bright white light “pearlescent pigments,” based on “a trick remain prohibitively expensive [8] and is observed. This process not only dem- copied from nature” [13], namely light as yet unavailable in paints for artists. onstrates what happens when differently interference. Ever since, (semi-)transpar- The greater stumbling block, however, colored reflections/lights are combined ent flakes generating “metal-like effects is the challenge the creative application but also illustrates the laws of additive .
Load more

Recommended publications
  • Diffractive Properties of Blue Morpho Butterfly Wings
    Diffractive Properties of Blue Morpho Butterfly Wings Mary Lalak and Paul Brackman Department of Physics and Astronomy, University of Georgia, Athens, Georgia 30602 (Dated: October 24, 2014) Many species of butterflies are known to produce beautiful iridescent colors when exposed to light from different angles. These affects can be attributed to a few different optical phenomena combined, the most prominent being reflective diffraction. Using common household items and with a budget of 50 dollars, we attempt to confirm the theory that the collection of ridges on the individual scales on the wing act as transmission gratings, as well as reflective. These results are quantified by the calculation of the ridge separation and comparing this distance to those observed by a scanning electron microscope photo. I. INTRODUCTION In studying the optical property of iridescence, three distinct mechanisms must be discussed. Thin film inter- ference, structured coloring, and reflective diffraction all contribute to the iridescent qualities of a surface. Thin film interference occurs when light strikes a film, some of it enters the film, and the rest is reflected off. The light transmitted through reflects off the bottom of the film and exits the film to interfere with the light that FIG. 1: Up-Close View of Scales from an Optical Microscope originally reflected off the surface of the film. This inter- ference pattern causes a spectrum of color to be visible from white light. Examples of thin film interference in- clude oil slicks and soap bubbles. Structural coloring oc- curs when the structure of the object itself (with various reflective surfaces) produces an interference resulting in vibrant colors.
    [Show full text]
  • Iridescence in Cooked Venison – an Optical Phenomenon
    Journal of Nutritional Health & Food Engineering Research Article Open Access Iridescence in cooked venison – an optical phenomenon Abstract Volume 8 Issue 2 - 2018 Iridescence in single myofibers from roast venison resembled multilayer interference in having multiple spectral peaks that were easily visible under water. The relationship HJ Swatland of iridescence to light scattering in roast venison was explored using the weighted- University of Guelph, Canada ordinate method of colorimetry. In iridescent myofibers, a reflectance ratio (400/700 nm) showing wavelength-dependent light scattering was correlated with HJ Swatland, Designation Professor CIE (Commission International de l’Éclairage) Y%, a measure of overall paleness Correspondence: Emeritus, University of Guelph, 33 Robinson Ave, Guelph, (r=0.48, P< 0.01). Hence, meat iridescence is an optical phenomenon. The underlying Ontario N1H 2Y8, Canada, Tel 519-821-7513, mechanism, subsurface multilayer interference, may be important for meat colorimetry. Email [email protected] venison, iridescence, interference, reflectance, meat color Keywords: Received: August 23, 2017 | Published: March 14, 2018 Introduction balanced pixel hues that have tricked your eyes to appear white; and when we perceive interference colors, complex interference spectra Iridescence is an enigmatic aspect of meat color with some practical trick our eyes again. As the order of interference increases, the colors 1–4 importance for consumers concerned about green colors in meat. appear to change from metallic
    [Show full text]
  • Octopus Consciousness: the Role of Perceptual Richness
    Review Octopus Consciousness: The Role of Perceptual Richness Jennifer Mather Department of Psychology, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada; [email protected] Abstract: It is always difficult to even advance possible dimensions of consciousness, but Birch et al., 2020 have suggested four possible dimensions and this review discusses the first, perceptual richness, with relation to octopuses. They advance acuity, bandwidth, and categorization power as possible components. It is first necessary to realize that sensory richness does not automatically lead to perceptual richness and this capacity may not be accessed by consciousness. Octopuses do not discriminate light wavelength frequency (color) but rather its plane of polarization, a dimension that we do not understand. Their eyes are laterally placed on the head, leading to monocular vision and head movements that give a sequential rather than simultaneous view of items, possibly consciously planned. Details of control of the rich sensorimotor system of the arms, with 3/5 of the neurons of the nervous system, may normally not be accessed to the brain and thus to consciousness. The chromatophore-based skin appearance system is likely open loop, and not available to the octopus’ vision. Conversely, in a laboratory situation that is not ecologically valid for the octopus, learning about shapes and extents of visual figures was extensive and flexible, likely consciously planned. Similarly, octopuses’ local place in and navigation around space can be guided by light polarization plane and visual landmark location and is learned and monitored. The complex array of chemical cues delivered by water and on surfaces does not fit neatly into the components above and has barely been tested but might easily be described as perceptually rich.
    [Show full text]
  • ESSENTIALS of METEOROLOGY (7Th Ed.) GLOSSARY
    ESSENTIALS OF METEOROLOGY (7th ed.) GLOSSARY Chapter 1 Aerosols Tiny suspended solid particles (dust, smoke, etc.) or liquid droplets that enter the atmosphere from either natural or human (anthropogenic) sources, such as the burning of fossil fuels. Sulfur-containing fossil fuels, such as coal, produce sulfate aerosols. Air density The ratio of the mass of a substance to the volume occupied by it. Air density is usually expressed as g/cm3 or kg/m3. Also See Density. Air pressure The pressure exerted by the mass of air above a given point, usually expressed in millibars (mb), inches of (atmospheric mercury (Hg) or in hectopascals (hPa). pressure) Atmosphere The envelope of gases that surround a planet and are held to it by the planet's gravitational attraction. The earth's atmosphere is mainly nitrogen and oxygen. Carbon dioxide (CO2) A colorless, odorless gas whose concentration is about 0.039 percent (390 ppm) in a volume of air near sea level. It is a selective absorber of infrared radiation and, consequently, it is important in the earth's atmospheric greenhouse effect. Solid CO2 is called dry ice. Climate The accumulation of daily and seasonal weather events over a long period of time. Front The transition zone between two distinct air masses. Hurricane A tropical cyclone having winds in excess of 64 knots (74 mi/hr). Ionosphere An electrified region of the upper atmosphere where fairly large concentrations of ions and free electrons exist. Lapse rate The rate at which an atmospheric variable (usually temperature) decreases with height. (See Environmental lapse rate.) Mesosphere The atmospheric layer between the stratosphere and the thermosphere.
    [Show full text]
  • Rainbow Peacock Spiders Inspire Miniature Super-Iridescent Optics
    ARTICLE DOI: 10.1038/s41467-017-02451-x OPEN Rainbow peacock spiders inspire miniature super- iridescent optics Bor-Kai Hsiung 1,8, Radwanul Hasan Siddique 2, Doekele G. Stavenga 3, Jürgen C. Otto4, Michael C. Allen5, Ying Liu6, Yong-Feng Lu 6, Dimitri D. Deheyn 5, Matthew D. Shawkey 1,7 & Todd A. Blackledge1 Colour produced by wavelength-dependent light scattering is a key component of visual communication in nature and acts particularly strongly in visual signalling by structurally- 1234567890 coloured animals during courtship. Two miniature peacock spiders (Maratus robinsoni and M. chrysomelas) court females using tiny structured scales (~ 40 × 10 μm2) that reflect the full visual spectrum. Using TEM and optical modelling, we show that the spiders’ scales have 2D nanogratings on microscale 3D convex surfaces with at least twice the resolving power of a conventional 2D diffraction grating of the same period. Whereas the long optical path lengths required for light-dispersive components to resolve individual wavelengths constrain current spectrometers to bulky sizes, our nano-3D printed prototypes demonstrate that the design principle of the peacock spiders’ scales could inspire novel, miniature light-dispersive components. 1 Department of Biology and Integrated Bioscience Program, The University of Akron, Akron, OH 44325, USA. 2 Department of Medical Engineering, California Institute of Technology, Pasadena, CA 91125, USA. 3 Department of Computational Physics, University of Groningen, 9747 AG Groningen, The Netherlands. 4 19 Grevillea Avenue, St. Ives, NSW 2075, Australia. 5 Scripps Institution of Oceanography (SIO), University of California, San Diego, La Jolla, CA 92093, USA. 6 Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
    [Show full text]
  • Diffraction Shading Models for Iridescent Surfaces
    DIFFRACTION SHADING MODELS FOR IRIDESCENT SURFACES Emmanuel Agu Francis S.Hill Jr Department of Computer Science Department of Electrical and Computer Engineering, Worcester Polytechnic Institute, University of Massachusetts, Amherst, Worcester, MA 01609, USA MA 01002, USA [email protected] [email protected] Abstract to the phenomenon of iridescence. Common sources of iridescent colors include diffraction gratings, opals and Diffraction and interference are optical phenomena some liquid crystals, hummingbird winds and some which split light into its component wavelengths, hence snakeskins. Diffraction, also referred to as a wavefront producing a full spectrum of iridescent colors. This splitting phenomenon is distinguished from paper develops comput er graphics models for iridescent interference, an amplitude-splitting phenomenon [2]. colors produced by diffractive media. Diffraction gratings, certain animal skins and the crystal structure A common problem in optics is that of determining the of some precious stones are known to produce outgoing light intensity, wavelength and color, given diffraction. Several techniques can be employed to that light is incident on the diffraction surface at a derive solutions to the diffraction problem including: certain angle and intensity and is comprised of specified (1)Electromagnetic boundary value methods wavelengths. In particular, a closed-form expression (2)Applying the Huygens-Fresnel principle (3)Applying relating incoming and outgoing light permits diffraction the Kirchoff-Fresnel theorem (4)Fourier optics. surfaces to be elegantly modelled in computer graphics. Previous work in developing diffraction models for computer graphics has used boundary value methods and Fourier optics but no models using Huygens- Several techniques have been employed in the optics Fresnel principle have been published.
    [Show full text]
  • The Structure and Optical Characters of Iridescent Glass
    Proc. Indian Acad. Sci. A9 371-381 (1939) The structure and optical characters of iridescent glass SIR C V RAMAN and V S RAJAGOPALAN Received April 29, 1939 1. Introduction In the museums of Europe will be found exhibited specimens of ancient glassware excavated from archaeological sites and distinguished by a very beautiful iridescence. Nearly a century ago, Sir David Brewster (1840, 1859, 1860, 1864) examined and described specimens of such glass. According to him, the iridescence of glass which has suffered decomposition is due to its lamellar structure; in other words, the material is an ensemble of thin films optically distinct from each other. In consequence of this structure, it exhibits a large reflecting power, presenting vivid colours both by reflection and by transmission, these being complementary. Brewster noticed that only rarely do the laminae possess specularly reflecting surfaces; in many cases their surfaces are rough due to the presence of a large number of small cavities which may lie separate or run into each other; in other cases again, according to him, the films are covered with concentric stratified structures presenting between crossed nicols the pheno- menon of a black cross. Brewster's explanation of the iridescence of ancient glass appears to have been accepted without question by all subsequent observers. Considerable interest naturally attaches to the question why the glass acquires with time a laminar structure which in its normal state it does not possess. It is a matter of common knowledge that glass under prolonged exposure to wind and weather or to the action of suitable chemical reagents often acquires a superficial iridescence, and attempts have not been lacking to accelerate this process of attack and thus to reproduce experimentally some of the structures observed and described by Brewster in ancient glass.
    [Show full text]
  • National Weather Service Glossary Page 1 of 254 03/15/08 05:23:27 PM National Weather Service Glossary
    National Weather Service Glossary Page 1 of 254 03/15/08 05:23:27 PM National Weather Service Glossary Source:http://www.weather.gov/glossary/ Table of Contents National Weather Service Glossary............................................................................................................2 #.............................................................................................................................................................2 A............................................................................................................................................................3 B..........................................................................................................................................................19 C..........................................................................................................................................................31 D..........................................................................................................................................................51 E...........................................................................................................................................................63 F...........................................................................................................................................................72 G..........................................................................................................................................................86
    [Show full text]
  • A Practical Extension to Microfacet Theory for the Modeling of Varying Iridescence Laurent Belcour, Pascal Barla
    A Practical Extension to Microfacet Theory for the Modeling of Varying Iridescence Laurent Belcour, Pascal Barla To cite this version: Laurent Belcour, Pascal Barla. A Practical Extension to Microfacet Theory for the Modeling of Varying Iridescence. ACM Transactions on Graphics, Association for Computing Machinery, 2017, 36 (4), pp.65. 10.1145/3072959.3073620. hal-01518344v2 HAL Id: hal-01518344 https://hal.archives-ouvertes.fr/hal-01518344v2 Submitted on 20 Jul 2017 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. A Practical Extension to Microfacet Theory for the Modeling of Varying Iridescence LAURENT BELCOUR, Unity Technologies PASCAL BARLA, Inria Classical microfacets Iridescent microfacets Goniochromatic eects Fig. 1. Material appearance such as that of leather is usually reproduced with microfacet models in computer graphics. A more realistic result is achieved by adding a thin-film coating that produces iridescent colors [Akin 2014]. We replace the classic Fresnel reflectance term with a new Airy reflectance term that accounts for iridescence due to thin-film interference. Our main contribution consists in an analytical integration of the high-frequency spectral oscillations exhibited by Airy reflectance, which is essential for practical rendering in RGB.
    [Show full text]
  • Cephalopod Guidelines
    Reference Resources Caveats from AAALAC’s Council on Accreditation regarding this resource: Guidelines for the Care and Welfare of Cephalopods in Research– A consensus based on an initiative by CephRes, FELASA and the Boyd Group *This reference was adopted by the Council on Accreditation with the following clarification and exceptions: The AAALAC International Council on Accreditation has adopted the “Guidelines for the Care and Welfare of Cephalopods in Research- A consensus based on an initiative by CephRes, FELASA and the Boyd Group” as a Reference Resource with the following two clarifications and one exception: Clarification: The acceptance of these guidelines as a Reference Resource by AAALAC International pertains only to the technical information provided, and not the regulatory stipulations or legal implications (e.g., European Directive 2010/63/EU) presented in this article. AAALAC International considers the information regarding the humane care of cephalopods, including capture, transport, housing, handling, disease detection/ prevention/treatment, survival surgery, husbandry and euthanasia of these sentient and highly intelligent invertebrate marine animals to be appropriate to apply during site visits. Although there are no current regulations or guidelines requiring oversight of the use of invertebrate species in research, teaching or testing in many countries, adhering to the principles of the 3Rs, justifying their use for research, commitment of appropriate resources and institutional oversight (IACUC or equivalent oversight body) is recommended for research activities involving these species. Clarification: Page 13 (4.2, Monitoring water quality) suggests that seawater parameters should be monitored and recorded at least daily, and that recorded information concerning the parameters that are monitored should be stored for at least 5 years.
    [Show full text]
  • Iridescence: More Than Meets The
    The First Annual Frontiers in Life Sciences Conference IRIDESCENCE More than Meets the Eye February 6 - 9, 2008 Arizona State University - School Of Life Sciences Old Main, Carson Ballroom, Tempe Campus photo credit: Melissa Meadows TABLE OF CONTENTS Overview . 2-3 Acknowledgements . 4-5 Daily Events . 6-7 Fashion Show . 8-11 Guest Speaker Biographies . 12-15 Conference organizers . 16 Oral Presentation Abstracts . 16-35 Poster Abstracts . 35-43 Subject Index . 44-45 photo credit: Tomatito26 | Dreamstime Stock Photos CONFERENCE OVERVIEW 2 A unique, integrative 4–day conference on iridescent colors in nature, Iridescence: More than Meets the Eye is a graduate student proposed and organized conference supported by the Frontiers in Life Sciences program in Arizona State University’s School of Life Sciences . This conference intends to connect diverse groups of researchers to catalyze synthetic cross– disciplinary discussions regarding iridescent coloration in nature, identify new avenues of research, and explore the potential for these stunning natural phenomena to provide novel insights in fields as divergent as materials science, sexual selection and primary science education . We invite you to join us for this exciting event February 6 – 9, 2008 at Old Main, Carson Ballroom, Tempe Campus . Each day of the conference will be dedicated to a specific area of study . We have invited twelve main speakers from all over the world and from disciplines ranging from biology to nanotechnology . The day will begin with a series of plenary–style talks by invited speakers, followed by shorter talks by other participants as time allows . Afternoon break–out sessions centered on the day’s topic will give interested participants a chance to discuss and share ideas, leading to new collaborations and several publications .
    [Show full text]
  • Identification of Genes Associated With
    Lemer et al. BMC Genomics (2015) 16:568 DOI 10.1186/s12864-015-1776-x RESEARCH ARTICLE Open Access Identification of genes associated with shell color in the black-lipped pearl oyster, Pinctada margaritifera Sarah Lemer1,2*, Denis Saulnier3, Yannick Gueguen3,4 and Serge Planes1 Background: Color polymorphism in the nacre of pteriomorphian bivalves is of great interest for the pearl culture industry. The nacreous layer of the Polynesian black-lipped pearl oyster Pinctada margaritifera exhibits a large array of color variation among individuals including reflections of blue, green, yellow and pink in all possible gradients. Although the heritability of nacre color variation patterns has been demonstrated by experimental crossing, little is known about the genes involved in these patterns. In this study, we identify a set of genes differentially expressed among extreme color phenotypes of P. margaritifera using a suppressive and subtractive hybridization (SSH) method comparing black phenotypes with full and half albino individuals. Results: Out of the 358 and 346 expressed sequence tags (ESTs) obtained by conducting two SSH libraries respectively, the expression patterns of 37 genes were tested with a real-time quantitative PCR (RT-qPCR) approach by pooling five individuals of each phenotype. The expression of 11 genes was subsequently estimated for each individual in order to detect inter-individual variation. Our results suggest that the color of the nacre is partially under the influence of genes involved in the biomineralization of the calcitic layer. A few genes involved in the formation of the aragonite tablets of the nacre layer and in the biosynthesis chain of melanin also showed differential expression patterns.
    [Show full text]