Bacterial Degradation of Black and White Feathers

Goldstein, Gérald; Flory, Kelly R.; Browne, Beth Ann; Majid, Samia; Ichida, Jann M.; Burtt, Edward H.

doi:10.1642/0004-8038(2004)121[0656:bdobaw]2.0.co;2

Cited by 155 publications

(85 citation statements)

References 8 publications

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“…Although black pigmentation in the wing may have had a role in the crypsis, communication and/or thermoregulation 4 of Archaeopteryx, such inferences cannot be made with any certainty. Similarly, in modern birds, melanins confer protection against feather-degrading bacteria that flourish in humid habitats 4,33,34 , but it is uncertain whether the dry climate of the Jurassic Solnhofen 1,35 would have provided sufficient evolutionary pressure to select for such an adaptation.…”

Section: Discussionmentioning

confidence: 99%

New evidence on the colour and nature of the isolated Archaeopteryx feather

et al. 2012

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Archaeopteryx has been regarded as an icon of evolution ever since its discovery from the Late Jurassic limestone deposits of solnhofen, Germany in 1861. Here we report the first evidence of colour from Archaeopteryx based on fossilized colour-imparting melanosomes discovered in this isolated feather specimen. using a phylogenetically diverse database of extant bird feathers, statistical analysis of melanosome morphology predicts that the original colour of this Archaeopteryx feather was black, with 95% probability. Furthermore, reexamination of the feather's morphology leads us to interpret it as an upper major primary covert, contrary to previous interpretations. Additional findings reveal that the specimen is preserved as an organosulphur residue, and that barbule microstructure identical to that of modern bird feathers had evolved as early as the Jurassic. As in extant birds, the extensive melanization would have provided structural advantages to the Archaeopteryx wing feather during this early evolutionary stage of dinosaur flight.

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Section: Discussionmentioning

confidence: 99%

New evidence on the colour and nature of the isolated Archaeopteryx feather

et al. 2012

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“…Finally, island plumage variation may actually be more strongly influenced by natural than sexual selection. For example, melanized black plumage may confer a selective advantage through abrasion resistance (Bonser 1995), resistance against bacterial degradation (Goldstein et al 2004) or crypsis (Endler 1990).…”

Section: (C) Implicationsmentioning

confidence: 99%

Concordant evolution of plumage colour, feather microstructure and a melanocortin receptor gene between mainland and island populations of a fairy–wren

Doucet

Shawkey

Rathburn

et al. 2004

Proc. R. Soc. Lond. B

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Studies of the patterns of diversification of birds on islands have contributed a great deal to the development of evolutionary theory. In white-winged fairy-wrens, Malurus leucopterus, mainland males develop a striking blue nuptial plumage whereas those on nearby islands develop black nuptial plumage. We explore the proximate basis for this divergence by combining microstructural feather analysis with an investigation of genetic variation at the melanocortin-1 receptor locus (MC1R). Fourier analysis revealed that the medullary keratin matrix (spongy layer) of the feather barbs of blue males was ordered at the appropriate nanoscale to produce the observed blue colour by coherent light scattering. Surprisingly, the feather barbs of black males also contained a spongy layer that could produce a similar blue colour. However, black males had more melanin in their barbs than blue males, and this melanin may effectively mask any structural colour produced by the spongy layer. Moreover, the presence of this spongy layer suggests that black island males evolved from a blue-plumaged ancestor. We also document concordant patterns of variation at the MC1R locus, as five amino acid substitutions were perfectly associated with the divergent blue and black plumage phenotypes. Thus, with the possible involvement of a melanocortin receptor locus, increased melanin density may mask the blue-producing microstructure in black island males, resulting in the divergence of plumage coloration between mainland and island white-winged fairy-wrens. Such mechanisms may also be responsible for plumage colour diversity across broader geographical and evolutionary scales.

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“…Melanins have a wide range of functions in birds, including physical protection (Barrowclough & Sibley 1980;Burtt 1986), protection from parasites (Goldstein et al 2004), camouflage and a variety of signalling functions (Bó kony et al 2003;Jawor & Breitwisch 2003;Roulin 2004). Here I review recent studies on the molecular genetic basis of melanism in birds that provide a framework for future studies involving more complex phenotypic changes both within and between species.…”

Section: Introductionmentioning

confidence: 99%

A window on the genetics of evolution:MC1Rand plumage colouration in birds

2005

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Melanins are a ubiquitous component of plumage colouration in birds and serve a wide variety of functions. Although the genetic control of melanism has been studied in chickens and other domestic species, little was known about the molecular genetics of melanin distribution in wild birds until recently. Studies have now revealed that a single locus, the melanocortin-1 receptor (MC1R) locus, is responsible for melanic polymorphisms in at least three unrelated species: the bananaquit, the snow goose and the arctic skua. Results show that melanism was a derived trait and allow other evolutionary inferences about the history of melanism to be made. The role of MC1R in plumage patterning is surprisingly diverse among different species. The conserved molecular basis for the evolution of melanism in birds and several other vertebrates is probably related to low pleiotropic effects at the MC1R.

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Bacterial Degradation of Black and White Feathers

Cited by 155 publications

References 8 publications

New evidence on the colour and nature of the isolated Archaeopteryx feather

New evidence on the colour and nature of the isolated Archaeopteryx feather

Concordant evolution of plumage colour, feather microstructure and a melanocortin receptor gene between mainland and island populations of a fairy–wren

A window on the genetics of evolution:MC1Rand plumage colouration in birds

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