ASSOCIATION BETWEEN SNP MARKERS AND MILK PRODUCTION TRAIT OF SWAMP BUFFALO

The research of association between SNP markers and milk production trait of swamp buffalo was conducted to identify polymorphisms of SNP markers associated with milk/day trait of swamp buffalo. Milk/day data and hair bud samples were collected from 28 second parity milking swamp buffalo at 2 to 3 months at farmer farm in Prachinburi province for DNA extraction. DNA samples were used for 40 SNP genotyping by Mass Array method. The results showed 10 polymorphism SNP and associated with milk/day trait of swamp buffalo (P<0.01). They were 3 groups: 1) associated hormones (2 Leptin), 2) energy balance (2 GHRL, 1 ARHGAP39 and 3 MC4R) and 3) immune system (1 BOLADQA1, 1 TFAP2D). The 2 SNPs of Leptin genes (from exon 2 and 3, AY495587.1), There were 2 genotypes of Leptin_2 SNP at G1072A mutation point (GG and GA). The average milk/day of GG and GA were 4.03+0.05 and 5.89+0.26 kg respectively (P<0.01). The mutation point of Leptin_5 was G3441A with 3 genotypes GG, GA and AA. The average milk/day of GG, GA and AA genotypes were 5.01+0.07, 4.83+0.10 and 4.95+0.19 kg respectively (P<0.01). The GHRL genes (EF583468.1) had 2 SNPs (GHRL_1 and GHRL_2). The GHRL_1 (A122G) had 3 genotypes. There were AA, AG and GG, with average milk/day 5.82+0.09, 3.94+0.13 and 5.02+0.07 kg respectively (P<0.01). There were 3 genotypes of GHRL_2 (T380C), TT, TC and CC. The average milk/day were 5.01+0.08, 4.38+0.13 and 5.45+0.08 kg, respectively (P<0.01). The BOLADQA1 (rs110525467, C-T) had 2 genotypes CC and TT. The average milk/day was 4.28+0.06 and 5.60+0.09 kg respectively (P<0.01). In consideration with the allele frequency, the Leptin_5 SNP (G3441A) was suitable to develop as MAS for milk/day trait. The SNP of GHRL_2(T380C) and BOLADQA1 (rs110525467) were moderate for MAS. However, 3 SNPs can be used as MAS for selection and breeding and introducing new genetics from outside herd for milk/day trait development of swamp buffalo in this farm.