A complex genomic rearrangement involving the endothelin 3 locus causes dermal hyperpigmentation in the chicken.
Dermal hyperpigmentation or Fibromelanosis (FM) is one of the few examples of skin pigmentation phenotypes in the chicken, where most other pigmentation variants influence feather color and patterning. The Silkie chicken is the most widespread and well-studied breed displaying this phenotype. The presence of the dominant FM allele results in extensive pigmentation of the dermal layer of skin and the majority of internal connective tissue. Here we identify the causal mutation of FM as an inverted duplication and junction of two genomic regions separated by more than 400 kb in wild-type individuals. One of these duplicated regions contains endothelin 3 (EDN3), a gene with a known role in promoting melanoblast proliferation. We show that EDN3 expression is increased in the developing Silkie embryo during the time in which melanoblasts are migrating, and elevated levels of expression are maintained in the adult skin tissue. We have examined four different chicken breeds from both Asia and Europe displaying dermal hyperpigmentation and conclude that the same structural variant underlies this phenotype in all chicken breeds. This complex genomic rearrangement causing a specific monogenic trait in the chicken illustrates how novel mutations with major phenotypic effects have been reused during breed formation in domestic animals.
Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
Ben
B
Dorshorst
Anna-Maja
AM
Molin
Carl-Johan
CJ
Rubin
Anna M
AM
Johansson
Lina
L
Strömstedt
Manh-Hung
MH
Pham
Chih-Feng
CF
Chen
Finn
F
Hallböök
Chris
C
Ashwell
Leif
L
Andersson
D000818:Animals; D001483:Base Sequence; D001947:Breeding; D049109:Cell Proliferation; D002642:Chick Embryo; D002645:Chickens / Q000235:genetics* / Q000254:growth & development*; D002874:Chromosome Mapping; D019334:Endothelin-3 / Q000235:genetics*; D005241:Feathers / Q000254:growth & development*; D020440:Gene Duplication; D018507:Gene Expression Regulation, Developmental; D015321:Gene Rearrangement; D016678:Genome; D008544:Melanocytes / Q000166:cytology / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D020641:Polymorphism, Single Nucleotide; D019655:Quantitative Trait, Heritable; D012880:Skin Pigmentation / Q000235:genetics*
D019334:Endothelin-3