Gene expression analysis identifies new candidate genes associated with the development of black skin spots in Corriedale sheep
- 246 Downloads
The white coat colour of sheep is an important economic trait. For unknown reasons, some animals are born with, and others develop with time, black skin spots that can also produce pigmented fibres. The presence of pigmented fibres in the white wool significantly decreases the fibre quality. The aim of this work was to study gene expression in black spots (with and without pigmented fibres) and white skin by microarray techniques, in order to identify the possible genes involved in the development of this trait. Five unrelated Corriedale sheep were used and, for each animal, the three possible comparisons (three different hybridisations) between the three samples of interest were performed. Differential gene expression patterns were analysed using different t-test approaches. Most of the major genes with well-known roles in skin pigmentation, e.g. ASIP, MC1R and C-KIT, showed no significant difference in the gene expression between white skin and black spots. On the other hand, many of the differentially expressed genes (raw P-value < 0.005) detected in this study, e.g. C-FOS, KLF4 and UFC1, fulfil biological functions that are plausible to be involved in the formation of black spots. The gene expression of C-FOS and KLF4, transcription factors involved in the cellular response to external factors such as ultraviolet light, was validated by quantitative polymerase chain reaction (PCR). This exploratory study provides a list of candidate genes that could be associated with the development of black skin spots that should be studied in more detail. Characterisation of these genes will enable us to discern the molecular mechanisms involved in the development of this feature and, hence, increase our understanding of melanocyte biology and skin pigmentation. In sheep, understanding this phenomenon is a first step towards developing molecular tools to assist in the selection against the presence of pigmented fibres in white wool.
KeywordsMicroarray analysis Pigmented fibre Sheep Skin pigmentation
We thank Gabriela Libisch and Gonzalo Grief (Unidad de Biología Molecular, Institut Pasteur de Montevideo) for their invaluable assistance in the laboratory work. This research was supported by grant FCE2007_547 from Agencia Nacional de Investigación e Innovación (Uruguay).
- Diaz S, Camilión C, Deferrari G, Fuenzalida H, Armstrong R, Booth C, Paladini A, Cabrera S, Casiccia C, Lovengreen C, Pedroni J, Rosales A, Zagarese H, Vernet M (2006) Ozone and UV radiation over southern South America: climatology and anomalies. Photochem Photobiol 82:834–843PubMedCrossRefGoogle Scholar
- Fleet MR (2002) Pigment prevention in sheep: complex or simple? Wool Technol Sheep Breed 50:410–416Google Scholar
- Fleet MR, Forrest JW, Walker SK, Rogers GE (2004) Foetal development of melanocyte populations in Merino wool-bearing skin. Wool Technol Sheep Breed 52:101–123Google Scholar
- Fleet MR, Foulds RA, Mahar TJ, Turk JA (2008) Relationship between pigmented fibre in raw and processed wool when other dark fibre is controlled—a review. Int J Sheep Wool Sci 56:40–59Google Scholar
- R Development Core Team (2009) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, AustriaGoogle Scholar
- Sponenberg DP (1997) Genetics of colour and hair texture. In: Piper LR, Ruvinsky A (eds) The genetics of sheep. CAB International. Wallingford, UK, pp. 51–85Google Scholar
- Urioste JI, Peñagaricano F, López R, Laporta J, Llaneza F, Lafuente C, Kremer, R (2008) Incidence of dark skin spots and pigmentation in commercial Corriedale flocks. In: Proceedings of the 10th World Conference on Animal Production, Cape Town, South Africa, 23–28 November 2008, p. 26Google Scholar