| alur, come scritto anche nell'articolo sulla genetica dei colori del pelo (in questa sezione!) non tutto il bianco deriva dalle stesse alterazioni.. Il bianco da depigmentazione legata al difetto della cresta neurale dervia da mancata formazione delle cellule del pigmento, mentre altri bianchi derivano da difetti nella sintesi del pigmento delle cellule stesse..
Letteratura scientifica ufficiale o divulgativa ce n'è a bizzeffe (credo di avere un centinaio di articoli a riguardo)..e di casi di problematiche nei furetti ne ho a mente parecchi, ma non sta a me tirarli fuori!!!! ;-) Molti sono postati nei post da me scritti in questa sezione. Altri riferimenti su altre specie..generali
Annu. Rev. Cell Dev. Biol. 2008. 24:425–46 Evolution of Coloration Patterns Meredith E. Protas and Nipam H. Patel
Current Genomics, 2000, 1, 223-242 223
Molecular Genetics of Pigmentation in Domestic Animals
Helge Klungland* and Dag Inge Våge
Abstract: While many wild animal species are relatively uniformly coloured, a wide variety of coat colours are found in domestic animals. Shift from natural selection towards criterias that are based on human preferences is most likely to account for the observed increase in coat colour variation. This makes domestic animals unique for studying gene function and gene regulation with regards to loci affecting pigmentation. Following an initial evolutionary discussion, this review will focus on two aspects of mammalian pigmentation; regulation of pigment synthesis and distribution of pigment producing cells. Molecular interaction between the G-protein coupled receptor MC1-R (melanocyte stimulating hormone receptor) and the agouti protein is the main regulatory system known to control the synthesis of eumelanin (brown or black pigment) versus phaeomelanin (red or yellow pigment). For both genes, mutations that explain phenotypical variants are characterised in several species. This includes numerous dominant-acting mutations of the MC1-R gene a constitutively activated receptor, and subsequently synthesis of black pigment. Additionally, it has been shown that the agouti gene, which is known to antagonise the MC1-R, is able to modify the expression of a wild-type MC1-R, as well as a semi-dominant variant of this receptor. Whereas agouti and extension often cause pigment switches, the distribution of pigment depends on proliferation and migration of neural crest derived melanocytes. Several genes, including the tyrosine kinase c-kit receptor and its ligand steel factor, regulate these processes. Functional mutations within the c-kit gene or variants of the ligand have been identified, and both loci are documented to influence the level of spotting.
Can Vet J. 2010 Jun;51(6):653-7. Coat color and coat color pattern-related neurologic and neuro-ophthalmic diseases. Webb AA, Cullen CL.
Un rticolo recentissimo sui cani
Science. 2009 Oct 2;326(5949):150-3. Epub 2009 Aug 27.
Coat variation in the domestic dog is governed by variants in three genes.
Cadieu E, Neff MW, Quignon P, Walsh K, Chase K, Parker HG, Vonholdt BM, Rhue A, Boyko A, Byers A, Wong A, Mosher DS, Elkahloun AG, Spady TC, André C, Lark KG, Cargill M, Bustamante CD, Wayne RK, Ostrander EA.
Coat color and type are essential characteristics of domestic dog breeds. Although the genetic basis of coat color has been well characterized, relatively little is known about the genes influencing coat growth pattern, length, and curl. We performed genome-wide association studies of more than 1000 dogs from 80 domestic breeds to identify genes associated with canine fur phenotypes. Taking advantage of both inter- and intrabreed variability, we identified distinct mutations in three genes, RSPO2, FGF5, and KRT71 (encoding R-spondin-2, fibroblast growth factor-5, and keratin-71, respectively), that together account for most coat phenotypes in purebred dogs in the United States. Thus, an array of varied and seemingly complex phenotypes can be reduced to the combinatorial effects of only a few genes.
Articolo riassuntivo sui cani
Anim Genet. 2007 Dec;38(6):539-49.
Genes affecting coat colour and pattern in domestic dogs: a review.
Schmutz SM, Berryere TG.
Tremendous progress has been made in identifying genes involved in pigmentation in dogs in the past few years. Comparative genomics has both aided and benefited from these findings. Seven genes that cause specific coat colours and/or patterns in dogs have been identified: melanocortin 1 receptor, tyrosinase related protein 1, agouti signal peptide, melanophilin, SILV (formerly PMEL17), microphthalmia-associated transcription factor and beta-defensin 103. Although not all alleles have been yet identified at each locus, DNA tests are available for many. The identification of these alleles has provided information on interactions in this complex set of genes involved in both pigmentation and neurological development. The review also discusses pleiotropic effects of some coat colour genes as they relate to disease. The alleles found in various breeds have shed light on some potential breed development histories and phylogenetic relationships. The information is of value to dog breeders who have selected for and against specific colours since breed standards and dog showing began in the late 1800s. Because coat colour is such a visible trait, this information will also be a valuable teaching resource.
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