Polymorphism in IGFALS gene and its association with scrotal circumference in Hu lambs

Figures & data

Table 1. Primer pairs designed for sheep IGFALS.

Primer name	Primer sequences (5′–3′)	GenBank accession number	Annealing temperature (°C)	Amplicon length (bp)
IGFALS-F IGFALS-R	TGACGGCACCCAGCTAACTCA TCCTCCCCTGCTCATCCCA	NC_040275.1	61.4 °C	848 bp

Table 2. Primer pairs designed for KASPar assay.

Gene	Primer	Primer sequence (5′–3′)
IGFALS	Primer_AlleleX	GAAGGTGACCAAGTTCATGCTTGATGGCAGGCAACGCTTCAC
	Primer_AlleleY	GAAGGTCGGAGTCAACGGATTTGATGGCAGGCAACGCTTCAG
	Primer_Common	TTTACAGGAGATGACAACCCACTGG

Figure 1. Descriptive statistics of scrotal circumference size at different stages. (A) The violin plot of scrotal circumference. (B) The coefficient of variation of scrotal circumference.

Table 3. Estimation of scrotal circumference variance components and heritability at different stages.

Items	σ^2a (±se)	σ^2e (±se)	h2 (±se)
Scrotal circumference100	6.120 ± 1.117	2.397 ± 0.957	0.719 ± 0.116
Scrotal circumference120	6.016 ± 1.420	4.395 ± 1.251	0.578 ± 0.126
Scrotal circumference140	2.856 ± 1.137	6.112 ± 1.058	0.318 ± 0.123
Scrotal circumference160	4.245 ± 1.274	5.320 ± 1.153	0.444 ± 0.126
Scrotal circumference180	4.691 ± 1.934	5.119 ± 1.742	0.4781 ± 0.186

Note: σ²_a: additive effect variance component; σ²_e: residual variance component; h₂: heritability.

Figure 2. PCR amplification of the target fragments of the ovine IGFALS genes. Note: M: DL2000 DNA Marker; 1–10: PCR products

Figure 3. Image of the sequencing peaks of sheep IGFALS g.918 G > C loci.

Figure 4. Kaspar–based single nucleotide polymorphism (SNP) genotyping of sheep IGFALS g.918 G > C.

Table 4. Genotype frequency, allele frequency, and genetic diversity of IGFALS g.918G > C sites.

Loci	Genotype	No.	Genotype frequency	Allele	Allele frequency	Ne	Ho	He	PIC	HWE p Values
IGFALS g.918 G > C	CC	987	0.73	C	0.845	1.355	0.738	0.262	0.228	0.082
	CG	315	0.23
	GG	51	0.04	G	0.155

Note: Ne: effective allele number; He: expected heterozygosity; Ho: expected homozygosity; PIC: polymorphism information content; HWE: Hardy–Weinberg equilibrium.

Table 5. Association of different genotypes due to SNP in IGFALS with the scrotal circumference in sheep.

Item	IGFALS g.918 G > A			p-Value
	CC	CG	GG
No	987	315	51
Scrotal circumference100 (cm)	18.230 ± 0.104^b	18.851 ± 0.185^a	19.443 ± 0.459^a	<0.01
Scrotal circumference120 (cm)	22.011 ± 0.119^b	22.657 ± 0.210^a	23.402 ± 0.523^a	<0.01
Scrotal circumference140 (cm)	25.604 ± 0.105^b	26.210 ± 0.187^a	26.153 ± 0.464^ab	<0.01
Scrotal circumference160 (cm)	26.901 ± 0.107^b	27.424 ± 0.190^a	27.663 ± 0.471^ab	<0.01
Scrotal circumference180 (cm)	26.829 ± 0.113^b	27.482 ± 0.200^a	27.896 ± 0.497^a	<0.01

Note: SNP: single nucleotide polymorphism. Vales for the phenotypic data are shown as the mean ± standard error. Different superscript lowercase letters against values in the same column indicate significant differences (p < 0.05).