Polymorphisms In CAPN1 And Their Association With Carcass And Meat Quality Traits In Yak

Calpain(CAPN), existing in almost all eukaryotes, is neutral cysteine endopeptidase which depends on Ca2+. CAPN1 gene belongs to calcium protease family and plays a major role in animal meat tenderization after slaughtered. In this study, the mutations at intron 1, intron 13 and intron 14 in CAPN1 gene in Gannan yak, Datong yak and Tianzhu white yak were detected by PCR-SSCP. The effects of these mutations on carcass and meat quality traits of Gannan yak were analyzed. The results are as follows:(1) In CAPN1 gene in Gannan yak, Datong yak and Tianzhu white yak, total five SNPs were detected that incloud g.100+606G>T mutation corresponding to alleles M and N in intron 1, g.22229+28G>A and g.22229+52C>A mutations corresponding to allele E, F and G in intron13, and g.22229+28G>A and g.22229+52C>A mutations corresponding to allele A, B, C and D intron 14. Moderate polymorphisms were found in intron 1, intron 13 and intron 14 in all of three yak populations.(2) Total 25 kinds of haplotypes were built in three yak populations which include 6 kinds of “intron 1-intron 13” haplotypes, 8 kinds of “intron 1-intron 14” haplotypes and 11 kinds of “intron 1-intron 13” haplotypes. linkage equilibriums were identified in yak populations as their D? and r2 value of three types of haplotype were 0.031-0.165 and 0.001-0.020, respectively.(3) Meat tenderness degree, water loss rate, eye muscle area of different age period Gannan yaks were regulated by genetic mutation of intron 1 of CAPN1. The genotype MM yak shear force was low and eye muscle area was high. The shear force of 3-years-old individual yak with genotype MM was significantly lower than that with genotype NN and MN(P< 0.05). The shear force of 5- years-old individual yak with genotype MM and NN was significantly lower than that with genotype MN(P< 0.05). The eye muscle area of 4- and 5-years-old individual yaks genotype MM was significantly higher than that with genotype NN. The yak with presence of allele N had lower value of eye muscle area, the eye muscle area of 4-years-old with presence allele N was significantly lower than those didn’t possess of allele N(P< 0.05). The genotype MM in 3~6-years-old yak water loss rate was high, the water loss rate of 6-years-old individual yak with genotype MM was significantly higher than that with genotype NN and MN(P< 0.05). The yak with presence of allele N had lower value of water loss rate, it means that allele N may increased water holding capacity after slaughter.(4) Eye muscle area and cooking rate of different age period Gannan yaks were regulated by genetic mutation of intron 13 of CAPN1. The eye muscle area of 4 year-old yaks with genotype EE was significantly higher than that with genotype FF and EF(P<0.05), and 6 year-old yaks with genotype EF was significantly higher than that with genotype EG(P<0.05). Gannan yak presence allele E or detection allele F could inceasing eye muscle area to a certain degree. The cooking rate of 6-year-old individual yak with genotype EE and EF was significantly lower than that with genotype FF and EG(P<0.05). The cooking rate of 4-years-old with presence allele E was significantly lower than those did’t possess of allele E(P<0.05).(5) Meat tenderness degree and carcass weight of different age period Gannan yaks were regulated by genetic mutation of intron 14 of CAPN1. The shear force of 3-years-old yaks with genotype AA was significantly lower than that with genotype CC(P< 0.05). The shear force of 6-years-old yaks with genotype AA, BB and AB was significantly lower than that with genotype CC(P< 0.05). The shear force of 5-years-old yaks with genotype AB was significantly higher than that with CC type yaks(P< 0.05). The carcass weight of 4- year-old yaks with genotype CC was significantly higher than other genotype yak(P<0.05). The carcass weight of 5-year-old yaks with genotype CC was significantly higher than that with genotype AB and AC(P<0.05). Allele C had the trend of increasing carcass weight of yak, the carcass weight of 4-years-old with presence allele C was significantly higher than those did’t possess of allele C(P<0.05).