association of the whole blood potassium polymorphism with resistant to saline in two sheep breeds of different climates of iran

abstract the whole blood potassium concentration has shown the bimodal distribution in sheep, which has been classified into lk and hk types; hk allele is recessive to lk with a single gene inheritance. this polymorphism showed different behavior in different environment, which could be due to adaptation process. this research was conducted on the zel and kermani breed research station, which kermani breed research station has been located in a hot and dry climate with saline drinking water for animals and zel breed research station has been located in a humid climate with normal drinking water for animals. kermani breed sheep: the whole blood potassium concentration of 188 animals ranged from 8 - 44 m eq/l. the curve of shown that the sheep could be divided into two subpopulation via lk having 8-18 m eq/l of k+ and hk having 23-44 m eq/l of k+ with mean of 12.086±0.2 m eq/l of k+ in the lk type and with mean of 32.614±0.5m eq/l of k+ in the hk types. the frequency of hk gene was found to be 0.902. concentration of sodium, calcium in whole blood were also determined, the mean and range of blood sodium concentration were 1737.36 and 343-5000.04 ppm respectively. the relationship between potassium and sodium concentrations in whole blood of sheep was significant. and negative estimated phenotypic correlation around -0.19 which was significant. the mean of whole blood sodium concentration was 3020.9 ppm and 2672.5 ppm for lk and hk respectively. remarkable differences in calcium and magnesium concentrations were not recognized between lk and hk types. zel breed sheep: the frequency distribution of blood potassium concentration in the sheep population is presented as a frequency curve. it is seen from the monomodal nature. the curve that the sheep couldnt be divided into two subpopulation and all of animal has shown lk genotype. blood potassium concentration ranged from 183.15 to 480.1ppm in zel sheep and the mean value of blood potassium concentration of zel lk animals was 277.37 and all of the zel animal were lk the ferquency of lk gene was found to be close to 1 in zel sheep.the relationship between potassium and sodium concentration in whole blood of sheep was significant. and negative estimated correlation around –0.35 which was significant. the mean of whole blood sodium concentration was 2806/1 ppm for lk sheep. animals with hk phenotype have active na-k-pump (i.e. concentration of na and k in cell regulate with consume energy) but the animal with lk phenotype, concentration of na and k regulate with simple diffusion and na-k-pump is semi activetherefore to regulate of na and k concentration in cell, the animal with hk genotype can better survive dry climate with nearly saline drinking water.