Genetic Polymorphisms For The Erythropoietin (EPO) Gene In Livestock Adapted To High-altitude Or Low-land Environments

Erythropoetin (EPO) is an endongenous hormone that is involved in theregulation of red blood cell production and genetic variation for erythropoetinproduction may be important in explaining the fitness of animals adapted tohigh-altitude environments. Individuals from Tibetan pigs, yak, sheep (Qiaoke, Oula,Ganja) and low-land pigs (Large White, Landrace, Duroc), cattle (Zaosheng), andsheep (Mongolian, Tan, Small-tailed Han, Texel) were evaluated for single nucleotidepolymorphisms at the erythropoetin locus to determine genetic variability for thislocus across adapted environment, species, and breed in species. The results are asfollows:In this study, different pig breeds of the EPO gene sequence measured pass,measured and had a yak, cattle and sheep EPO3,4,5exon and the first3,4intronicsequences.1. Primers for the porcine EPO gene were developed from the NCBI sequence(AJ249746) submitted for the European wild boar. A total of7haplotypes uniquefrom the European wild boar were identified in Tibetan pig, Large White, Landrace,and Duroc EPO gene in27variable sites. Therefore, including the European wild boarand the4breeds studied,11sequences resulting in8haplotypes were identified.Haplotype1was associated with the European wild boar, haplotype2with Duroc, andhaplotypes3with Landrace and Large White breeds. Haplotypes4,5,6,7, and8wereassociated with Tibetan pigs, suggesting the possibility of unique genetics associatedwith adaptation to high-altitude environments. Compared to sequences of Duroc,Landrace, and Large White, two mutations were noted in Tibetan pigs: a deletion of Gat site51bp from the5' upstream flanking sequence and an A to G substitution at site397bp from the5' location in first intron of the EPO gene It is noteworthy that therewas a14bp deletion in one Tibetan pig in the1236bp to1249bp. The porcine EPOgene encodes194amino acids, and only two of the six mutations of the mRNAsequences identified in this study were in the CDS and there was only one missensemutations resulting in changes in amino acids in the Tibetan pigs. Specifically, in the mRNA an A�'T mutation at343bp, and a T�'C mutation at479bp, with the A�'T missense mutation causing a tyrosine (tyr into, Y)�'phenylalanine (phe, F)mutation.2. Primers for the bovine and ovine EPO genes were developed from the NCBIsequence (EF374049) submitted for the Chinese Sanjiang Yellow Cattle. Sequencingof the EPO gene partial fragment of yak and cattle (Zaosheng cattle) resulted inidentification of eight haplotypes involving31variable sites within the sequences.Haplotype1was associated with Sanjiang cattle and one Zaosheng animal from thisstudy. Haplotypes5,6,7, and8were associated with Zaosheng cattle whilehaplotypes2,3, and4were associated with yak, with3of the5yak classified ashaplotype2. For cattle6mutations were identified. At21bp was a C�'Tsubstitution, at619bp there was a T deletion, at690bp there was a G�'Asubstitution, at877bp there was a C�'T substitution, at1156bp there was a T�'C substitution and at1230bp there was a A�'G substation. For yak,3base pairsubstitutions were identified: A�'G at177bp, T�'A at338bp, and C�'T at842bp. Contrasting yak and cattle nucleotide sequences, differences were found asfollows: A (cattle)�'G (yak) at264bp, T (cattle)�'A (yak) at265bp, T (cattle)�'C (yak) at295bp, G (cattle)�'T (yak) at581bp, C (cattle)�'T (yak) at1084bp, a17bp deletion in cattle at564to580bp,missense mutations at338bp, T (cattle)�'A (yak), leading to the change of leucine (L)�'glutamate (Q), consistent withother scholars. A new missense mutation was discovered in cattle at690bp (G�'A),resulting in alanine (A)�'threonine (T) coding.3. Primers for the bovine and ovine EPO genes were developed from the NCBIsequence (EF374049) submitted for the Chinese Sanjiang Yellow Cattle. Evaluationof the EPO haplotyptes in Qiaoke, Oula, Ganja Tibetan sheep and Texel, Small-tailHan, Tan, and Mongolian sheep identified6haplotypes with variation at4sites in thesequence. In5of the breeds, there was a substitution mutation at1206bp (C�'G), asubstitution mutation for Ganja and Qiaoke breeds at1076bp (C�'A), asubstitution mutation in Small-tail Han at268bp (G�'A), and a C�'T substitution at1161bp for Qiaoke and Mongolian breeds. Haplotype1was identifiedin all5sheep breeds, Haplotype2was identified in all breeds except Small-tail Han,Haplotype3was identified only in Ganja and Qiaoke breeds, Haplotype4wasidentified in Qiaoke and Mongolian breeds, Haplotype5was unique to Small-tail Han,and Haplotype6was unique to Mongolian sheep.