title: Adaptive variation in beach mice produced by two interacting pigmentation genes.
abstract: Little is known about the genetic basis of ecologically important morphological variation such as the diverse color patterns of mammals. Here we identify genetic changes contributing to an adaptive difference in color pattern between two subspecies of oldfield mice (Peromyscus polionotus). One mainland subspecies has a cryptic dark brown dorsal coat, while a younger beach-dwelling subspecies has a lighter coat produced by natural selection for camouflage on pale coastal sand dunes. Using genome-wide linkage mapping, we identified three chromosomal regions (two of major and one of minor effect) associated with differences in pigmentation traits. Two candidate genes, the melanocortin-1 receptor (Mc1r) and its antagonist, the Agouti signaling protein (Agouti), map to independent regions that together are responsible for most of the difference in pigmentation between subspecies. A derived mutation in the coding region of Mc1r, rather than change in its expression level, contributes to light pigmentation. Conversely, beach mice have a derived increase in Agouti mRNA expression but no changes in protein sequence. These two genes also interact epistatically: the phenotypic effects of Mc1r are visible only in genetic backgrounds containing the derived Agouti allele. These results demonstrate that cryptic coloration can be based largely on a few interacting genes of major effect.
authors: Division of Biological Sciences, University of California San Diego, La Jolla, California, United States of America.
authors: Cynthia C
authors: CC
authors: Steiner
authors: Jesse N
authors: JN
authors: Weber
authors: Hopi E
authors: HE
authors: Hoekstra
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D000818:Animals; D003116:Color; D004843:Epistasis, Genetic; D008040:Genetic Linkage; D014644:Genetic Variation; D023281:Genomics; D051379:Mice; D009154:Mutation; D010542:Peromyscus / Q000235:genetics*; D010858:Pigmentation / Q000235:genetics*; D044102:Receptor, Melanocortin, Type 1 / Q000235:genetics*; D013045:Species Specificity
chemical_list: D044102:Receptor, Melanocortin, Type 1
references: Heredity (Edinb). 1999 Nov;83 (Pt 5):613-24
references: 10620035
references: Genetics. 2001 Feb;157(2):875-84
references: 11157004
references: Mamm Genome. 2001 Dec;12(12):930-2
references: 11707780
references: Evolution. 2002 Nov;56(11):2262-77
references: 12487356
references: Proc Natl Acad Sci U S A. 2003 Apr 29;100(9):5268-73
references: 12704245
references: Pigment Cell Res. 2003 Aug;16(4):333-44
references: 12859616
references: Evol Dev. 2003 Nov-Dec;5(6):579-92
references: 14984040
references: Nature. 2004 Apr 15;428(6984):717-23
references: 15085123
references: Nature. 2005 Feb 3;433(7025):481-7
references: 15690032
references: Nat Rev Genet. 2005 Feb;6(2):119-27
references: 15716908
references: Science. 2005 Mar 25;307(5717):1928-33
references: 15790847
references: PLoS Biol. 2005 Jul;3(7):e245
references: 16000021
references: Nat Genet. 2006 Jan;38(1):107-11
references: 16341223
references: Genetics. 2006 Jun;173(2):735-57
references: 16489214
references: Proc Natl Acad Sci U S A. 1929 Jun 15;15(6):481-93
references: 16577208
references: Proc Natl Acad Sci U S A. 1929 Feb 15;15(2):110-20
references: 16587454
references: Heredity (Edinb). 2006 Sep;97(3):222-34
references: 16823403
references: Science. 2006 Jul 7;313(5783):101-4
references: 16825572
references: Evolution. 2007 May;61(5):995-1016
references: 17492956
references: Am Nat. 1992 Nov;140(5):725-42
references: 19426041
references: Evolution. 1974 Dec;28(4):689-692
references: 28564823
references: J Hered. 1978 Sep-Oct;69(5):295-8
references: 744871
references: Genes Dev. 1994 Feb 15;8(4):481-90
references: 8125260
references: Cell. 1993 Mar 26;72(6):827-34
references: 8458079
references: Nature. 1996 Mar 14;380(6570):149-52
references: 8600386
references: Trends Genet. 1996 Aug;12(8):299-305
references: 8783939
references: Genetics. 1996 Sep;144(1):265-77
references: 8878692
references: Nat Genet. 1997 Mar;15(3):311-5
references: 9054949