Apolipoprotein E (apoE) phenotypes weredetermined in 199 unrelated native sheep (Khalkhas line)of Central Mongolia, using a polyacrylamide gelisoelectric focusing-immunoblotting technique, and theplasma lipid levels in different phenotypes wereassayed enzymatically. Twenty-eight phenotypes wereidentified in this sheep. In addition to all thepreviously detected seven apoE variants composing thephenotypes, four new variants were discovered, which werecalled E8, E9, E10, and E11. From the population data,these were found to be genetically controlled by fourcodominant alleles, designated APOE8,APOE9, APOE10,and APOE11, based on the same modeof inheritance as in the seven variants. These alleleswere detected at a low frequency, in the range of 0.005to 0.0126. The Khalkhas sheep differed mostsignificantly from the Baruwal and Lampuchhre sheep of Nepaland the Vietnamese sheep with respect to the allelefrequencies found in some Asian local sheep previouslyexamined. Type 1/1 and/or 2/7 sheep had significantly higher plasma levels of total cholesterol andlow-density lipoprotein cholesterol than type 7/7 sheep(P < 0.05 and/or P <0.02).