ABSTRACT
<p><b>OBJECTIVE</b>In order to study the effect of the polymorphism at the exon2 region of the (3-LG allele gene on milk composition and yield.</p><p><b>METHODS</b>The single-strand conformation polymorphism method (PCR-SSCP) was used to analyze for polymorphism the exon2 region of the 3-LG gene (NCBI accession number: DQ489319) in Chinese Holstein.</p><p><b>RESULTS</b>Eight SSCP patterns were detected in the fragments: ab, abc, abd, abe, abcd, abce, abde and abcde, and the patterns frequencies as follows: 0.14, 0.10, 0.27, 0.23, 0.05, 0.04, 0.11 and 0.06 (P < 0.05); Six single nucleotide polymorphism (SNP) were detected in this study: sitel C>T, site2 T>C, site3 C>T, site4 C>C, site5 C> A, site6 A>T or C, and the polymorphism infonnation content (PIC) of these SNPs were in median or high polymorphism (PIC > 0.25).</p><p><b>CONCLUSION</b>These SNPs at the exon2 region of the beta-LG gene were remarkably and affected milk performance traits (milk yield, protein and fat contents) in Chinese Holstein.</p>