Position 211 of the Prp Gene in Dairy Goats
A study of Ontario goat herds affected with scrapie disease in 2014 (Srithayakumar et al., 2016) identified variation at the prion protein gene (PrP) that was strongly associated with scrapie resistance and susceptibility. Animals with two copies of the PrP gene coding for the arginine (RR ) at position 211 were highly susceptible, animals with one gene coding for arginine and one coding for glutamine at 211 (RQ) were weakly susceptible and animals with two copies of the gene coding for glutamine at 211 (QQ) were resistant. |
Position 146 of the PrP Gene in Meat Goats
Similar studies conducted in Europe have also discovered an association of the amino acid serine (S) at position 146 with resistance in mixed breeds of goats (Papasavva-Stylianou et al., 2007, 2011., Oritz-Pelaez et al., 2015., Fragkiadaki et al., 2011.,). More specifically, in Dutch goats, breeds of Boers and Nubians had the highest frequency of having the146 (S) genotype (Windig et al., 2016) .A comparison of variation of the PrP gene of scrapie affected Cyprus goats showed all homozygotes with the amino acid aspargines (NN) at position 146 (Papasavva-Stylianou et al., 2007). Therefore, animals with two copies of aspargine (N) at position 146 appear to be highly susceptible, animals with one gene for serine and one for aspargine at 146 (NS) appear weakly susceptible and animals with two copies of the gene coding for serine at 146 (SS) appear highly resistant. |
Position 222 of the PrP Gene in Toggenburg Breeds
Position 222 has also been shown to be important in conferring resistance in European studies. A study in the UK on scrapie affected animals found a correlation of having glutamine (Q) at position 222 with susceptibility and lysine (K) at position 222 with resistance (Vaccari et al., 2006, Aguilar-Calvo et al., 2015). More specifically, the frequency of (K) at 222 was the highest in Toggenburg breeds (Windig et al.,2016, White et al., 2008). |
Risk Factor |
Position 146 |
Position 211 |
Position 222 |
Highly Susceptible |
NN |
RR |
QQ |
Weakly Susceptible |
NS |
RQ |
QK |
Resistant |
SS |
QQ |
KK |