caa a22 4500 386392803 CHVBK 20180307112125.0 cr unu---uuuuu 161130e198902 xx s 000 0 eng 10.1017/S0016672300027865 doi S0016672300027865 pii (NATIONALLICENCE)cambridge-10.1017/S0016672300027865 Evidence of a unique developmental mechanism specifying both wool follicle density and fibre size in sheep selected for single skin and fleece characters [Elektronische Daten] 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. Copyright © Cambridge University Press 1989 Moore G. P. M. CSIRO, Division of Animal Production, P.O. Box 239, Blacktown, NSW 2148, Australia Jackson N. CSIRO, Division of Animal Production, P.O. Box 239, Blacktown, NSW 2148, Australia Lax J. CSIRO, Division of Animal Production, P.O. Box 239, Blacktown, NSW 2148, Australia Genetical Research Cambridge University Press 53/1(1989-02), 57-62 0016-6723 53:1<57 1989 53 GRH https://doi.org/10.1017/S0016672300027865 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S0016672300027865 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Moore G. P. M. CSIRO, Division of Animal Production, P.O. Box 239, Blacktown, NSW 2148, Australia NATIONALLICENCE 700 1- Jackson N. CSIRO, Division of Animal Production, P.O. Box 239, Blacktown, NSW 2148, Australia NATIONALLICENCE 700 1- Lax J. CSIRO, Division of Animal Production, P.O. Box 239, Blacktown, NSW 2148, Australia NATIONALLICENCE 773 0- Genetical Research Cambridge University Press 53/1(1989-02), 57-62 0016-6723 53:1<57 1989 53 GRH CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge