The genetic basis of adaptive melanism in pocket mice

Nachman, Michael W.; Hoekstra, Hopi E.; D'Agostino, Susan L.

doi:10.1073/pnas.0431157100

Cited by 480 publications

(456 citation statements)

References 29 publications

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“…2003) while also providing valuable insights into sexual selection (Andersson 1994), adaptive evolution (Nachman et al. 2003), gene action (Kaelin and Barsh 2013), and the inheritance of genetic traits in general (Kaelin and Barsh, 2013). Intriguingly, coloration has also been linked to fitness variation in several species (Kruger et al.…”

Section: Introductionmentioning

confidence: 99%

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Born blonde: a recessive loss‐of‐function mutation in the melanocortin 1 receptor is associated with cream coat coloration inAntarctic fur seals

Peters

Humble

Kröcker

et al. 2016

Ecology and Evolution

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Although the genetic basis of color variation has been extensively studied in humans and domestic animals, the genetic polymorphisms responsible for different color morphs remain to be elucidated in many wild vertebrate species. For example, hypopigmentation has been observed in numerous marine mammal species but the underlying mutations have not been identified. A particularly compelling candidate gene for explaining color polymorphism is the melanocortin 1 receptor (MC1R), which plays a key role in the regulation of pigment production. We therefore used Antarctic fur seals (Arctocephalus gazella) as a highly tractable marine mammal system with which to test for an association between nucleotide variation at the MC1R and melanin‐based coat color phenotypes. By sequencing 70 wild‐type individuals with dark‐colored coats and 26 hypopigmented individuals with cream‐colored coats, we identified a nonsynonymous mutation that results in the substitution of serine with phenylalanine at an evolutionarily highly conserved structural domain. All of the hypopigmented individuals were homozygous for the allele coding for phenylalanine, consistent with a recessive loss‐of‐function allele. In order to test for cryptic population structure, which can generate artefactual associations, and to evaluate whether homozygosity at the MC1R could be indicative of low genome‐wide heterozygosity, we also genotyped all of the individuals at 50 polymorphic microsatellite loci. We were unable to detect any population structure and also found that wild‐type and hypopigmented individuals did not differ significantly in their standardized multilocus heterozygosity. Such a lack of association implies that hypopigmented individuals are unlikely to suffer disproportionately from inbreeding depression, and hence, we have no reason to believe that they are at a selective disadvantage in the wider population.

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Section: Introductionmentioning

confidence: 99%

“…2003; Nachman et al. 2003) probably due to the difficulty of designing PCR primers in nonmodel organisms that lack genomic resources.…”

Section: Introductionmentioning

confidence: 99%

Born blonde: a recessive loss‐of‐function mutation in the melanocortin 1 receptor is associated with cream coat coloration inAntarctic fur seals

Peters

Humble

Kröcker

et al. 2016

Ecology and Evolution

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“…The broad phenotypic variation of vertebrates observed in nature is one of the questions that have long intrigued evolutionary biologists, including its adaptive significance and genetic basis. Despite the interest in the subject, relatively few studies have addressed the association between phenotypes in natural populations and the environments in which organisms occur, aiming to investigate evolutionary processes involved in the generation and maintenance of coloration diversity and the environmental characteristics that influence the adaptive significance of phenotypes [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Ecology and Evolution of Melanism in Big Cats: Case Study with Black Leopards and Jaguars

Silva¹

2017

Big Cats

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Variations in animal coloration have intrigued evolutionary biologists for a long time. Among the observed pigmentation polymorphisms, melanism has been reported in multiple organisms (influencing several biological factors), and classical hypothesis has suggested that such variant can present adaptive advantages under certain ecological conditions. In leopards (Panthera pardus) and jaguars (Panthera onca), melanism is caused by recessive and dominant mutations in the ASIP and MC1R genes, respectively. This chapter is focused on melanism in these two species, aiming to analyze its geographic pattern. About 623 leopard and 980 jaguar records that were used as baseline for modeling and statistical analyses were obtained. The frequency of melanism was 10% for both species. In leopards, melanism was present in five subspecies and strongly associated with moist forests, especially in Southeast Asia. In jaguars, melanism was totally absent from open and periodically flooded landscapes; in contrast, forests displayed a frequency that was similar to the expectations. The analyses of the environmental predictors suggest a relevant role for factors such as moisture and temperature. These observations support the hypothesis that melanism in big cats is not a neutral polymorphism (influenced by natural selection), leading to a nonrandom geographic distribution of this coloration phenotype.

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“…Their approach is based on the observation that all-trans retinoic acid produces clinical remissions by inducing differentiation of acute promyelocytic leukemias harboring a mutated retinoic acid receptor alpha 6 . They developed a surrogate marker approach that uses post-treatment gene expression signatures in AML cell lines as the read-out for screening the ability of candidate compounds to induce differentiation of AML cells (Fig.…”

Section: A New Twistmentioning

confidence: 99%

“…pigmentation and cuticular decorations in insects and vertebrates [6][7][8][9] . More frequently, morphological differences involve several major-effect genes as well as weaker modifiers 8,[10][11][12] .…”

Section: N E W S a N D V I E W Smentioning

confidence: 99%

Making a better worm

Kopp

2004

Nat Genet

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The genetic basis of phenotypic evolution is one of the most intriguing questions in biology [1][2][3] . Much of our recent progress in this field has used the candidate gene approach (Fig. 1) C. elegans is distinguished from its nearest relatives by two unique features of its excretory system: a short excretory duct and high salt tolerance. Phylogenetic analysis showed that both features were derived and appeared only recently in C. elegans evolution (Fig. 1b) 4 . The development of derived traits in C. elegans depends on the expression of the zinc finger transcription factor lin-48 in the excretory duct cell. In lin-48 mutants, both excretory duct morphology and salt tolerance revert to the ancestral condition (Fig. 1a) 5 . This prompted Wang and Chamberlin to examine lin-48 expression and function in other worm species. The results were notable. In the relatives of C. elegans that have long excretory ducts and low salt tolerance, lin-48 was not expressed in the excretory duct cell (Fig. 1b), and lin-48 transgenes from any of these species could restore the development of derived features in C. elegans lin-48 mutants (Fig. 1c). Together, these results suggested that evolutionary changes in the expression, but not the function, of lin-48 had a key role in the origin of new morphological and physiological traits.The exact nature of this role would not have become clear were it not for Wang and Chamberlin's asking the question: Would forcing the more primitive species to express lin-48 in excretory duct cells be sufficient to confer the derived traits? The answer was both yes and no. Expression of lin-48 in the duct cell in C. briggsae, the closest relative of C. elegans, resulted in a C. elegans-like excretory duct morphology but did not give C. briggsae a higher salt tolerance (Fig. 1c). A probable historical scenario is that a regulatory change in a single gene, lin-48, led to the evolution of new morphology, but other loci had to change before the worm could acquire greater salt tolerance. Single genes, big effectsThese results send both a promise and a note of caution to scientists who study the evolution of development. By the very nature of their discipline, developmental biologists are inclined to believe in, and look for, individual genes that account for a large proportion of phenotypic differences between species. Wang and Chamberlin's paper confirms once more that this is not a fool's errand: not only do such major-effect genes exist, but their existence can be proven conclusively by functional tests. At the same time, we are cautioned about the dangers of making historical inferences based solely on mutant phenotypes and gene expression patterns. Without the gene replacement tests, we would not have learned that the morphology and physiology of the worm excretory system are separable and follow different modes of evolution (monogenic versus polygenic).Although the field of evolutionary developmental genetics is still too young to make sweeping generalizations, major-effect genes seem to be a common f...

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The genetic basis of adaptive melanism in pocket mice

Cited by 480 publications

References 29 publications

Born blonde: a recessive loss‐of‐function mutation in the melanocortin 1 receptor is associated with cream coat coloration inAntarctic fur seals

Born blonde: a recessive loss‐of‐function mutation in the melanocortin 1 receptor is associated with cream coat coloration inAntarctic fur seals

Ecology and Evolution of Melanism in Big Cats: Case Study with Black Leopards and Jaguars

Making a better worm

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