Characterisation of HSP70 promoter-polymorphism in autochthonous Norwegian cattle breeds

Abstract

By performing this study on autochthonous cattle breeds from different climate zones we wanted to test if any of these had higher abilities to adapt to heat stress on the basis of the polymorphism of the promoter region of HSP70. The theory was that a connection could be found between the climatic conditions and the conscious and non- conscious selection for heat resistance. Previous studies performed on a small population of NRF from Kysnes farm in Norway compared with HG indicated that this could be the case. This time we wanted to perform a larger study with a larger sample material and also include another autochthonous Norwegian breed, in this case the STN. The STN and the larger sample material of NRF were genotyped for AP2 box mutations and compared with the previously found results. The STN had a more expected frequency of the wild type allele. This can be because of a lower environmental heat average in Scandinavia, where an adequate heat response might not be as important, and is possibly non- consciously deselected. Surprisingly, the NRF stock from Kysnes farm and the NRF stock from GENO were not as similar as expected. Instead the NRF stock from GENO was more similar to the HG population. Since the NRF population is not actively selected for heat resistance, we suspect that other roles of the HSP70 might lead to a non-conscious selection of this and therefore also a high frequency of the wild type allele, however further studies needs to be done to support this theory.