Developmental mechanisms of stripe patterns in rodents.
Mammalian colour patterns are among the most recognizable characteristics found in nature and can have a profound impact on fitness. However, little is known about the mechanisms underlying the formation and subsequent evolution of these patterns. Here we show that, in the African striped mouse (Rhabdomys pumilio), periodic dorsal stripes result from underlying differences in melanocyte maturation, which give rise to spatial variation in hair colour. We identify the transcription factor ALX3 as a regulator of this process. In embryonic dorsal skin, patterned expression of Alx3 precedes pigment stripes and acts to directly repress Mitf, a master regulator of melanocyte differentiation, thereby giving rise to light-coloured hair. Moreover, Alx3 is upregulated in the light stripes of chipmunks, which have independently evolved a similar dorsal pattern. Our results show a previously undescribed mechanism for modulating spatial variation in hair colour and provide insights into how phenotypic novelty evolves.
Howard Hughes Medical Institute, Departments of Organismic &Evolutionary Biology and Molecular &Cellular Biology, Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts 02138, USA.
Ricardo
R
Mallarino
HudsonAlpha Institute for Biotechnology, Huntsville, Alabama 35806, USA.|Department of Genetics, Stanford University School of Medicine, Stanford, California 94305, USA.
Corneliu
C
Henegar
Instituto de Investigaciones Biomédicas Alberto Sols (CSIC/UAM) and Ciber de Diabetes y Enfermedades Metabólicas Asociadas (Ciberdem), Madrid 28029, Spain.
Mercedes
M
Mirasierra
Center for Interdisciplinary Research in Biology, Collège de France, Paris 75005, France.
Marie
M
Manceau
Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France.|School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg 2000, South Africa.
Carsten
C
Schradin
Instituto de Investigaciones Biomédicas Alberto Sols (CSIC/UAM) and Ciber de Diabetes y Enfermedades Metabólicas Asociadas (Ciberdem), Madrid 28029, Spain.
Mario
M
Vallejo
Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA.
Slobodan
S
Beronja
HudsonAlpha Institute for Biotechnology, Huntsville, Alabama 35806, USA.|Department of Genetics, Stanford University School of Medicine, Stanford, California 94305, USA.
Gregory S
GS
Barsh
Howard Hughes Medical Institute, Departments of Organismic &Evolutionary Biology and Molecular &Cellular Biology, Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts 02138, USA.
Hopi E
HE
Hoekstra
D000818:Animals; D005075:Biological Evolution; D019521:Body Patterning / Q000235:genetics; D002454:Cell Differentiation; D018507:Gene Expression Regulation, Developmental; D006200:Hair Color / Q000235:genetics; D018398:Homeodomain Proteins / Q000378:metabolism; D008543:Melanins / Q000096:biosynthesis; D008544:Melanocytes / Q000166:cytology / Q000378:metabolism; D051379:Mice; D051739:Microphthalmia-Associated Transcription Factor / Q000037:antagonists & inhibitors / Q000378:metabolism; D051189:Murinae / Q000196:embryology* / Q000235:genetics* / Q000502:physiology; D010641:Phenotype; D011401:Promoter Regions, Genetic / Q000235:genetics; D012589:Sciuridae / Q000235:genetics; D012867:Skin / Q000196:embryology
D018398:Homeodomain Proteins; D008543:Melanins; D051739:Microphthalmia-Associated Transcription Factor