Apolipoprotein E polymorphism and plasma lipid levels in Native Mongolian sheep

Area of Science:

• Genetics
• Biochemistry
• Animal Science

Background:

• Apolipoprotein E (apoE) plays a crucial role in lipid metabolism.
• Understanding apoE polymorphism in livestock is important for breeding and health management.
• Previous studies have characterized apoE in various sheep breeds, but data on Mongolian Khalkhas sheep is limited.

Purpose of the Study:

• To determine the apolipoprotein E (apoE) phenotypes in native Mongolian Khalkhas sheep.
• To identify and characterize new apoE variants and their genetic control.
• To investigate the association between different apoE phenotypes and plasma lipid levels.

Main Methods:

• Polyacrylamide gel isoelectric focusing-immunoblotting technique for apoE phenotyping.
• Enzymatic assays for quantifying plasma lipid levels (total cholesterol, LDL cholesterol).
• Population genetics analysis to determine allele frequencies and inheritance patterns.

Main Results:

• Twenty-eight apoE phenotypes were identified in 199 Khalkhas sheep.
• Four novel apoE variants (E8, E9, E10, E11) were discovered, controlled by four codominant alleles (APOE8-11).
• Allele frequencies for the new variants ranged from 0.005 to 0.0126.
• Khalkhas sheep apoE allele frequencies differed significantly from other Asian sheep breeds.
• Sheep with type 1/1 and/or 2/7 apoE phenotypes exhibited significantly higher plasma total and LDL cholesterol compared to type 7/7.

Conclusions:

• The Mongolian Khalkhas sheep population exhibits significant apoE genetic diversity, including novel variants.
• Apolipoprotein E genotype is a significant determinant of plasma lipid profiles in Khalkhas sheep.
• Findings contribute to understanding apoE genetics in Asian sheep and have implications for lipid metabolism research.