Recessive and dominant inheritance patterns associated with synonymous differences in wool fibre curvature and medullation

Figures & data

Figure 1. The relationship between fibre diameter (µm) and medullation (%) in the fleeces of lambs at shearing that were judged lustrous (open symbols) or wild-type (closed symbols) at birth. The progeny of Razzle (diamonds), Fazil (circles), Dazzle (squares) and Basil (crosses).

Table 1. Summary of average fibre diameter and average fibre curvature of samples from lambs and yearlings that were the progeny of two sires (‘Razzle' and ‘Dazzle') exhibiting phenotypic segregation that suggested dominant inheritance of lustre in the birth coat from Scobie et al. (2021) and the progeny of two sires (‘Basil' and ‘Fazil') exhibiting segregation that suggested recessive inheritance of lustre in a second mating from Scobie et al. (2023). The second-generation progeny of one sire (‘Fazil') are indicated (*).

Sire group	Fibre curvature (°/mm)		Fibre diameter (µm)
	Wild-type	Lustre	Wild-type	Lustre
Lamb shearing
Razzle	67.5	22.8	23.9	24.2
Dazzle	56.2	24.5	27.9	25.7
Basil	43.1		27.5
Fazil	43.8		27.9
Fazil*	46.5	21.1	26.3	29.2
Yearling shearing
Razzle	74.1	29.8	27.2	25.4
Dazzle	55.0	28.1	32.0	30.0
Basil	43.4		30.7
Fazil	45.4		30.3
Fazil *	56.9	41.6	29.6	30.5

Table 2. The percentage of fibres carrying a medulla (medullation %) in samples of wool from lambs and yearlings from the first mating of four different sires and one sire (*) mated back to ewe progeny from the first mating. Progeny of ‘Razzle' and ‘Dazzle' suggested dominant inheritance of lustre at birth, while the progeny of ‘Basil' and ‘Fazil' suggested recessive inheritance. Standard error of the mean is in parentheses. Various comparisons within groups and the associated P values are listed.

Sire	medullation (%)		comparison	group	P value
	Wild-type	Lustre
Lamb shearing
Razzle	4.8 (±1.7)	44.2 (±8.4)	Razzle vs Dazzle	Wild-type	P = 0.988
Dazzle	4.9 (±0.8)	38.1 (±11.1)	Razzle vs Dazzle	Lustre	P = 0.459
			Lustre vs wild-type	First generation	P < 0.001
Basil	14.7 (±3.0)		Basil vs Fazil	Wild-type	P = 0.572
Fazil	17.4 (±3.2)		Dominant vs recessive	First generation	P = 0.002
Fazil *	9.5 (±2.6)	54.6 (±6.0)	Lustre vs Wild-type	Second generation	P < 0.001
			First vs second generation	Wild type	P = 0.219
Yearling shearing
Razzle	1.8 (±0.5)	20.0 (±7.3)	Razzle vs Dazzle	Wild-type	P = 0.987
Dazzle	1.8 (±0.3)	19.1 (±7.3)	Razzle vs Dazzle	Lustre	P = 0.885
			Lustre vs wild-type	First generation	P < 0.001
Basil	4.0 (±1.3)		Basil vs Fazil	Wild-type	P = 0.692
Fazil	5.5 (±1.9)		Dominant vs recessive	First generation	P = 0.276
Fazil *	4.0 (±1.7)	22.6 (±8.2)	Lustre vs Wild-type	Second generation	P < 0.001
			First vs second generation	Wild type	P = 0.858

Scobie DR, van Koten C, Richena M, Plowman JE, Harland DP. 2021. Dominant mutation(s) for low fibre curvature in the wool of sheep. New Zealand Journal of Animal Science and Production. 81:112–116.

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Scobie DR, Richena M, van Koten C, Plowman JE, Lloyd H, Harland DP. 2023. Recessive mutation for low fibre curvature in the wool of sheep. Small Ruminant Research. 221:106934. doi:10.1016/j.smallrumres.2023.106934.

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