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Evidence of a unique developmental mechanism specifying both wool follicle density and fibre size in sheep selected for single skin and fleece characters

Published online by Cambridge University Press:  14 April 2009

G. P. M. Moore ,
N. Jackson  and
J. Lax
G. P. M. Moore*
Affiliation:
CSIRO, Division of Animal Production, P.O. Box 239, Blacktown, NSW 2148, Australia
N. Jackson
Affiliation:
CSIRO, Division of Animal Production, P.O. Box 239, Blacktown, NSW 2148, Australia
J. Lax
Affiliation:
CSIRO, Division of Animal Production, P.O. Box 239, Blacktown, NSW 2148, Australia
*
†Corresponding author G. P. M. Moore.

Summary

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Skin and fleece traits have been characterized in four lines of Merino sheep selected for high- and low-fibre diameter (D±) and staple length (L±) from a medium-woolled flock. Over a period of 20 years, each line responded in the desired direction, producing fleeces composed of thick or thin fibres and long or short wool staples. However, variations in the amounts of wool grown that might be expected from these procedures were compensated by changes in unselected characters. Thus a predicted difference in fleece weights between high and low staple length lines was reduced by an increase in fibre crimp frequency in L− sheep. Similarly, changes induced in fibre diameter in the D lines resulted in small effects on fleece weight in comparison to the large (and inverse) effects on follicle numbers. Towards the end of the selection regime, mean follicle density in D− sheep was twice that of D+ sheep. This intriguing response within the follicle population was examined further: an analysis of the relationship between follicle density and fibre diameter amongst the four lines revealed a highly significant, negative linear correlation. The implication of this statistical association is that the numbers of follicles initiated in skin during foetal life had a direct bearing on the sizes of wool fibres eventually produced. It was concluded that both features must be under the control of a single developmental mechanism. Since the expression of each of the characters is separated in time, the mechanism must be activated during the earlier event, i.e. at or before the phase of follicle initiation.

Type
Research Article
Information
Genetics Research , Volume 53 , Issue 1 , February 1989 , pp. 57 - 62
Copyright
Copyright © Cambridge University Press 1989

References

Adler, R. (1987). Nature and nurture in the differentiation of retinal photoreceptors and neurons. Cell Differentiation 20, 183–188.CrossRefGoogle ScholarPubMed
Auber, L. (1950). The anatomy of follicles producing wool-fibres with special reference to keratinization. Transactions of the Royal Society of Edinburgh 62, 191–254.Google Scholar
Carter, H. B. & Clarke, W. H. (1957). The hair follicle group and skin follicle population of Australian Merino sheep. Australian Journal of Agricultural Research 8, 91–108.CrossRefGoogle Scholar
Cohen, J. (1965). The dermal papilla. In Biology of the Skin and Hair Growth (ed. Lyne, A. G. and Short, B. F.), pp. 183–199, Sydney: Angus & Robertson.Google Scholar
Fraser, A. S. (1951). Competition between skin follicles in sheep. Nature 167, 202–203.CrossRefGoogle ScholarPubMed
Fraser, A. S., & Short, B. F. (1952). Competition between skin follicles in sheep. Australian Journal of Agricultural Research 3, 445–452.Google Scholar
Fraser, A. S. & Short, B. F. (1960). The Biology of the Fleece. Animal Research Laboratories Technical Paper No. 3, Commonwealth Scientific and Industrial Research Organisation, Australia, pp. 1–108.Google Scholar
Galpin, N. (1948). A study of wool growth. II. Mean fibre thickness, density of fibre population, the area of skin covered by fibre and the mean fibre length. Journal of Agricultural Science 38, 303–313.Google Scholar
Hardy, M. H. & Lyne, A. G. (1956). The prenatal development of wool follicles in Merino sheep. Australian Journal of Biological Sciences 9, 423–441.Google Scholar
Henderson, A. E. (1965). Relationship of wool follicle and wool fibre dimensions. In Biology of the Skin and Hair Growth (ed. Lyne, A. G. and Short, B. F.), pp. 447–465. Sydney: Angus and Robertson.Google Scholar
Ibrahim, L. & Wright, E. A. (1982). A quantitative study of hair growth using mouse and rat vibrissal follicles. Journal of Embryology and Experimental Morphology 72, 209–224.Google ScholarPubMed
Jackson, N. & Downes, A. M. (1979). The fibre diameter profile of wool staples from individual sheep. Australian Journal of Agricultural Research 30, 163–171.CrossRefGoogle Scholar
Kollar, E. J. (1970). The induction of hair follicles by embryonic dermal papillae. Journal of Investigative Dermatology 55, 374–378.Google Scholar
Moore, G. P. M. & Jackson, N. (1984). An hypothesis implicating a founder cell population in the regulation of wool follicle formation and distribution in the sheep. Journal of Embryology and Experimental Morphology 82, Suppl. 1, 259.Google Scholar
Nagorcka, B. N. & Mooney, J. R. (1985). The role of a reaction-diffusion system in the initiation of primary hair follicles. Journal of Theoretical Biology 114, 243–272.Google Scholar
Oliver, R. F. (1970). The induction of hair follicle formation in the adult hooded rat by vibrissa dermal papillae. Journal of Embryology and Experimental Morphology 23, 219–236.Google ScholarPubMed
Pisansarakit, P. & Moore, G. P. M. (1986). The induction of hair follicles in mouse skin by rat vibrissa dermal papillae. Journal of Embryology and Experimental Morphology 94, 113–119.Google Scholar
Reis, P. J., (1979). Effects of amino acids on the growth and properties of wool. In Physiological and Environmental Limitation to Wool Growth (ed. Black, J. L. and Reis, P. J.), pp. 223–242. Armidale: University of New England Publishing Unit.Google Scholar
Rendel, J. M. & Nay, T. (1978). Selection for high and low ratio and high and low primary density in Merino sheep. Australian Journal of Agricultural Research 29, 1077–1086.CrossRefGoogle Scholar
Rudall, K. M. (1956). The size and shape of the papilla in wool follicles. In Proceedings of the International Wool Textile Research Conference Australia, volume F, Histology of Wool and Hair and of the Wool follicle, pp. 9–25. Melbourne: Commonwealth Scientific and Industrial Research Organisation Australia.Google Scholar
Ryder, M. L. & Stephenson, S. K. (1968). Wool Growth, pp. 1–805. New York: Academic Press.Google Scholar
Schinckel, P. G. (1961). Mitotic activity in wool follicle bulbs. Australian Journal of Biological Sciences 14, 659–676.CrossRefGoogle Scholar
Turner, H. N., Brooker, M. G. & Dolling, C. H. S. (1970). Response to selection in Australian Merino sheep. III. Single character selection for high and low values of wool weight and its components. Australian Journal of Agricultural Research 21, 955–984.Google Scholar
Turner, H. N., Hayman, R. H., Riches, J. H., Roberts, N. F. & Wilson, L. T. (1953). Physical definition of sheep and their fleece for breeding and husbandry studies. Commonwealth Scientific and Industrial Research Organisation Divisional Report No. 4.Google Scholar
Wilson, P. A. & Short, B. F. (1979). Cell proliferation and cortical cell production in relation to wool growth. Australian Journal of Biological Sciences 32, 317–327.CrossRefGoogle ScholarPubMed