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Pigment evolution

Ryosuke Kita, Hunter B Fraser
Sun-exposure is a key environmental variable in the study of human evolution. Several skin-pigmentation genes serve as classical examples of positive selection, suggesting that sun-exposure has significantly shaped worldwide genomic variation. Here we investigate the interaction between genetic variation and sun-exposure, and how this impacts gene expression regulation. Using RNA-Seq data from 607 human skin samples, we identified thousands of transcripts that are differentially expressed between sun-exposed skin and non-sun-exposed skin...
October 2016: PLoS Genetics
Russell A Ligon, Richard K Simpson, Nicholas A Mason, Geoffrey E Hill, Kevin J McGraw
The ornaments used by animals to mediate social interactions are diverse, and by reconstructing their evolutionary pathways we can gain new insights into the mechanisms underlying ornamental innovation and variability. Here, we examine variation in plumage carotenoids among the true finches (Aves: Fringillidae) using biochemical and comparative phylogenetic analyses to reconstruct the evolutionary history of carotenoid states and evaluate competing models of carotenoid evolution. Our comparative analyses reveal that the most likely ancestor of finches used dietary carotenoids as yellow plumage colorants, and that the ability to metabolically modify dietary carotenoids into more complex pigments arose secondarily once finches began to use modified carotenoids to create red plumage...
October 19, 2016: Evolution; International Journal of Organic Evolution
Chaoyang Hu, Quanlin Li, Xuefang Shen, Sheng Quan, Hong Lin, Lei Duan, Yifa Wang, Qian Luo, Guorun Qu, Qing Han, Yuan Lu, Dabing Zhang, Zheng Yuan, Jianxin Shi
Elucidation of the metabolic pathways determining pigmentation and their underlying regulatory mechanisms in maize kernels is of high importance in attempts to improve the nutritional composition of our food. In this study, we compared dynamics in the transcriptome and metabolome between colored SW93 and white SW48 by integrating RNA-Seq and non-targeted metabolomics. Our data revealed that expression of enzyme coding genes and levels of primary metabolites decreased gradually from 11 to 21 DAP, corresponding well with the physiological change of developing maize kernels from differentiation through reserve accumulation to maturation, which was cultivar independent...
October 14, 2016: Scientific Reports
Yongxia Cui, Beng Kah Song, Lin-Feng Li, Ya-Ling Li, Zhongyun Huang, Ana L Caicedo, Yulin Jia, Kenneth M Olsen
Weedy rice is a conspecific form of cultivated rice (Oryza sativa L.) that infests rice fields and results in severe crop losses. Weed strains in different world regions appear to have originated multiple times from different domesticated and/or wild rice progenitors. In the case of Malaysian weedy rice, a multiple-origin model has been proposed based on neutral markers and analyses of domestication genes for hull color and seed shattering. Here we examined variation in pericarp (bran) color and its molecular basis to address how this trait evolved in Malaysian weeds and its possible role in weed adaptation...
October 11, 2016: G3: Genes—Genomes—Genetics
Jose Bernardo Quintos, Juanita K Hodax, Bryn A Gonzales-Ellis, Chanika Phornphutkul, Michael P Wajnrajch, Charlotte M Boney
Kearns-Sayre syndrome (KSS) is characterized by external ophthalmoplegia, retinal pigmentation and cardiac conduction defects due to mitochondrial DNA (mtDNA) deletions. Short stature and growth hormone (GH) deficiency have been reported in KSS, but data on GH treatment is limited. We describe the clinical presentation, phenotype evolution, and response to GH in a patient with KSS and report data on eight additional KSS patients from the KIGS database. Our patient with KSS and GH deficiency achieved a final adult height at -0...
October 8, 2016: Journal of Pediatric Endocrinology & Metabolism: JPEM
Kristopher J L Irizarry, Randall L Bryden
Color variation provides the opportunity to investigate the genetic basis of evolution and selection. Reptiles are less studied than mammals. Comparative genomics approaches allow for knowledge gained in one species to be leveraged for use in another species. We describe a comparative vertebrate analysis of conserved regulatory modules in pythons aimed at assessing bioinformatics evidence that transcription factors important in mammalian pigmentation phenotypes may also be important in python pigmentation phenotypes...
2016: Advances in Bioinformatics
James Barber
About 3 billion years ago an enzyme emerged which would dramatically change the chemical composition of our planet and set in motion an unprecedented explosion in biological activity. This enzyme used solar energy to power the thermodynamically and chemically demanding reaction of water splitting. In so doing it provided biology with an unlimited supply of reducing equivalents needed to convert carbon dioxide into the organic molecules of life while at the same time produced oxygen to transform our planetary atmosphere from an anaerobic to an aerobic state...
January 2016: Quarterly Reviews of Biophysics
Almut Kelber
Colour vision-the ability to discriminate spectral differences irrespective of variations in intensity-has two basic requirements: (1) photoreceptors with different spectral sensitivities, and (2) neural comparison of signals from these photoreceptors. Major progress has been made understanding the evolution of the basic stages of colour vision-opsin pigments, screening pigments, and the first neurons coding chromatic opponency, and similarities between mammals and insects point to general mechanisms. However, much work is still needed to unravel full colour pathways in various animals...
September 17, 2016: Current Opinion in Neurobiology
Héloïse Bastide, Jeremy D Lange, Justin B Lack, Amir Yassin, John E Pool
Unraveling the genetic architecture of adaptive phenotypic divergence is a fundamental quest in evolutionary biology. In Drosophila melanogaster, high-altitude melanism has evolved in separate mountain ranges in sub-Saharan Africa, potentially as an adaptation to UV intensity. We investigated the genetic basis of this melanism in three populations using a new bulk segregant analysis mapping method. We identified 19 distinct QTL regions from 9 mapping crosses, with several QTL peaks overlapping between two or all populations, and yet different crosses involving the same melanic population commonly yielded distinct QTLs...
September 16, 2016: Genetics
Esther García-de Blas, Rafael Mateo, Carlos Alonso-Alvarez
Colorful ornaments have been the focus of sexual selection studies since the work of Darwin. Yellow to red coloration is often produced by carotenoid pigments. Different hypotheses have been formulated to explain the evolution of these traits as signals of individual quality. Many of these hypotheses involve the existence of a signal production cost. The carotenoids necessary for signaling can only be obtained from food. In this line, carotenoid-based signals could reveal an individual's capacity to find sufficient dietary pigments...
2016: PeerJ
Wen-Sung Chung, N Justin Marshall
Previous investigations of vision and visual pigment evolution in aquatic predators have focused on fish and crustaceans, generally ignoring the cephalopods. Since the first cephalopod opsin was sequenced in late 1980s, we now have data on over 50 cephalopod opsins, prompting this functional and phylogenetic examination. Much of this data does not specifically examine the visual pigment spectral absorbance position (λmax) relative to environment or lifestyle, and cephalopod opsin functional adaptation and visual ecology remain largely unknown...
September 14, 2016: Proceedings. Biological Sciences
Alessandro Alboresi, Clotilde Le Quiniou, Sathish K N Yadav, Martin Scholz, Andrea Meneghesso, Caterina Gerotto, Diana Simionato, Michael Hippler, Egbert J Boekema, Roberta Croce, Tomas Morosinotto
Photosystem I (PSI) is a pigment protein complex catalyzing the light-driven electron transport from plastocyanin to ferredoxin in oxygenic photosynthetic organisms. Several PSI subunits are highly conserved in cyanobacteria, algae and plants, whereas others are distributed differentially in the various organisms. Here we characterized the structural and functional properties of PSI purified from the heterokont alga Nannochloropsis gaditana, showing that it is organized as a supercomplex including a core complex and an outer antenna, as in plants and other eukaryotic algae...
September 13, 2016: New Phytologist
Zhirong Li, Graham Peers, Rachel M Dent, Yong Bai, Scarlett Y Yang, Wiebke Apel, Lauriebeth Leonelli, Krishna K Niyogi
Plants, algae and cyanobacteria need to regulate photosynthetic light harvesting in response to the constantly changing light environment. Rapid adjustments are required to maintain fitness because of a trade-off between efficient solar energy conversion and photoprotection. The xanthophyll cycle, in which the carotenoid pigment violaxanthin is reversibly converted into zeaxanthin, is ubiquitous among green algae and plants and is necessary for the regulation of light harvesting, protection from oxidative stress and adaptation to different light conditions(1,2)...
2016: Nature Plants
M Emília Santos, Laura Baldo, Langyu Gu, Nicolas Boileau, Zuzana Musilova, Walter Salzburger
BACKGROUND: Understanding the genetic basis of novel traits is a central topic in evolutionary biology. Two novel pigmentation phenotypes, egg-spots and blotches, emerged during the rapid diversification of East African cichlid fishes. Egg-spots are circular pigmentation markings on the anal fins of hundreds of derived haplochromine cichlids species, whereas blotches are patches of conspicuous anal fin pigmentation with ill-defined boundaries that occur in few species that belong to basal cichlid lineages...
2016: BMC Genomics
Antonio Gavalás-Olea, Susana Álvarez, Pilar Riobó, Francisco Rodríguez, José L Garrido, Belén Vaz
We report the isolation from the green dinoflagellate Lepidodinium chlorophorum and structural characterization of a new carotenoid termed lepidoxanthin (1), determined to be (3S,5R,6S,3'R,6'R)-5,6-epoxy-19-(2-decenoyloxy)-19'-acetoxy-4',5'-didehydro-5,6,5',6'-tetrahydro-β,ε-carotene-3,3'-diol. Its until now unidentified 19,19'-diacyloxy substitution constitutes a chemical signature that can aid in unraveling the evolutionary course of this unicellular algae based on the proposed biosynthethic pathway.
September 16, 2016: Organic Letters
Matthew H Koski, Tia-Lynn Ashman
Divergence in reproductive traits between closely-related species that co-occur contributes to speciation by reducing interspecific gene flow. In flowering plants, greater floral divergence in sympatry than allopatry may reflect reproductive character displacement (RCD) by means of divergent pollinator-mediated selection or mating system evolution. However, environmental filtering (EF) would prevail for floral traits under stronger selection by abiotic factors than pollination, and lead to sympatric taxa being more phenotypically similar...
August 26, 2016: Evolution; International Journal of Organic Evolution
Steffen Schmitz-Valckenberg, Srinivas Sadda, Giovanni Staurenghi, Emily Y Chew, Monika Fleckenstein, Frank G Holz
PURPOSE: There is a lack of agreement regarding the types of lesions and clinical conditions that should be included in the term "geographic atrophy." Varied and conflicting views prevail throughout the literature and are currently used by retinal experts and other health care professionals. METHODS: We reviewed the nominal definition of the term "geographic atrophy" and conducted a search of the ophthalmologic literature focusing on preceding terminologies and the first citations of the term "geographic atrophy" secondary to age-related macular degeneration...
August 22, 2016: Retina
Sarah A Signor, Yang Liu, Mark Rebeiz, Artyom Kopp
Convergent evolution provides a type of natural replication that can be exploited to understand the roles of contingency and constraint in the evolution of phenotypes and the gene networks that control their development. For sex-specific traits, convergence offers the additional opportunity for testing whether the same gene networks follow different evolutionary trends in males versus females. Here, we use an unbiased, systematic mapping approach to compare the genetic basis of evolutionary changes in male-limited pigmentation in several pairs of Drosophila species that represent independent evolutionary transitions...
September 26, 2016: Current Biology: CB
Amir Yassin, Emily K Delaney, Adam J Reddiex, Thaddeus D Seher, Héloïse Bastide, Nicholas C Appleton, Justin B Lack, Jean R David, Stephen F Chenoweth, John E Pool, Artyom Kopp
Sex-limited polymorphisms are an intriguing form of sexual dimorphism that offer unique opportunities to reconstruct the evolutionary changes that decouple male and female traits encoded by a shared genome. We investigated the genetic basis of a Mendelian female-limited color dimorphism (FLCD) that segregates in natural populations of more than 20 species of the Drosophila montium subgroup. In these species, females have alternative abdominal color morphs, light and dark, whereas males have only one color morph in each species...
September 26, 2016: Current Biology: CB
Liping Ran, Mingxue Pi, Jian Wu, Jinjin Jiang, Youping Wang
Brassicaceae is at the forefront of evolution because of its frequent hybridization. Hybridization is responsible for the induction of widespread genetic and phenotype changes, making it important in agricultural production. In this study, we obtained resynthesized allotetraploid Brassica napus by performing interspecific crossing of B. rapa × B. oleracea combined with embryo rescue. We applied light microscopy and electronic microscopy to analyze the microstructure and ultrastructure of seeds of diploid parents and their allotetraploid progeny...
August 19, 2016: Protoplasma
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