Table 3 Effects of p.A41P mutation in myogenic factor 5 (MYF5) on muscle fiber characteristics and economic traits in 429 Yorkshire pigs

Traits	p.A41P Genotype			Additive	Dominant	Significance
	CC (29)	CG (226)	GG (174)			G	A	D
Muscle fiber characteristics
Total fiber number (×103)	1,169±41.2	1,226±18.4	1,177±20.5	–8.906	105.2	†	ns	*
Fiber number per unit area (/mm2)	234.6±6.36	242.5±2.85	241.6±3.17	–7.061	8.748	ns	ns	ns
CSA of fibers (μm2)	4,392±114.2	4,215±51.1	4,217±56.9	174.5	–179.9	ns	ns	ns
Fiber number composition (%)
Type I	11.03±0.76X	9.17±0.34Y	9.03±0.38Y	2.006	–1.717	*	*	†
Type IIa	14.65±0.95	14.70±0.42	15.17±0.47	–0.515	–0.430	ns	ns	ns
Type IIb	74.32±1.18	76.13±0.53	75.81±0.59	–1.490	2.145	ns	ns	ns
Fiber area composition (%)
Type I	8.08±0.55X	6.75±0.25Y	6.76±0.27Y	1.323	–1.330	*	*	†
Type IIa	8.84±0.61	8.77±0.27	9.09±0.31	–0.250	–0.396	ns	ns	ns
Type IIb	83.08±0.84	84.48±0.37	84.15±0.42	–1.075	1.726	ns	ns	ns
Lean meat production
Loin–eye area (cm2)	49.76±1.24XY	50.59±0.55X	48.68±0.62Y	1.079	2.739	*	*	†
Backfat thickness (mm)	22.28±0.79	21.00±0.35	20.91±0.39	1.362	–1.189	ns	ns	ns
Meat quality
pH45min	6.12±0.05	6.14±0.02	6.16±0.02	–0.037	–0.008	ns	ns	ns
Drip loss (%)	3.56±0.37	3.33±0.17	3.02±0.19	0.545	0.087	ns	ns	ns
Filter–fluid uptake (mg)	30.41±2.74X	27.75±1.22X	23.58±1.37Y	6.837	1.500	**	*	ns
Lightness (L*)	46.67±0.49	46.13±0.22	46.19±0.24	0.478	–0.598	ns	ns	ns

Different superscript letters (X and Y) indicate significant differences between genotypes at p<0.05.
Significance levels for genotype (G), additive (A), and dominant (D) effects: ns, not significant
^† p<0.10
^* p<0.05
^** p<0.01.
CSA, cross sectional area.