Gajra B, Candlish J K, Heng C K, Mak J W, Saha N
Biochemistry Department, Faculty of Medicine, National Unviersity of Singapore, Singapore.
Hum Biol. 1997 Oct;69(5):629-40.
Associations among seven apolipoprotein B (APOB) gene polymorphisms [C-T promoter site; Leu-Ala-Leu signal peptide (SP) insertion/deletion; AG C,G site at codon 71; AG A1,D site at codon 591; XbaI site at codon 2488; AG H,I site at codon 3611; and AG T,Z site at codon 4154] were investigated in 195 members of an Orang Asli (aborigine) population from western Malaysia. Frequencies of the rare alleles for all these polymorphisms turned out to be low when compared with European but not Asian populations. The AG H,I site was not polymorphic. The highly polymorphic sites are in linkage disequilibrium among themselves, as shown by their delta values: SP 24,27 and AG C,G, 0.68; SP 24,27 and AG A1,D, 0.71; XbaI and AG C,G, 0.64; XbaI and AG A1,D, 0.57; SP 24,27 and XbaI, 0.48; and AG C,G and AG A1,D, 0.68. Ten unequivocal haplotypes on the basis of six sites (excluding the promoter polymorphism) were observed, and they represent 80% of the sample. The frequency of haplotype SP27,G,A1,X-,I,T, defined by the common homozygotes at all the sites for the APOB gene was 0.7, compared with 0.22 in Europeans. The ancestral haplotype SP27,G,D,X-,I,T was present at low frequency (0.01) in both the Orang Asli and Europeans. A cladogram constructed on the basis of haplotypes in the Orang Asli shows two different lines of evolution and that other haplotypes evolved by subsequent mutations on the ancestral haplotype.
在来自马来西亚西部的195名原住民奥朗阿斯利人（Orang Asli）群体成员中，研究了七种载脂蛋白B（APOB）基因多态性[C-T启动子位点；亮氨酸-丙氨酸-亮氨酸信号肽（SP）插入/缺失；密码子71处的AG C、G位点；密码子591处的AG A1、D位点；密码子2488处的XbaI位点；密码子3611处的AG H、I位点；以及密码子4154处的AG T、Z位点]之间的关联。与欧洲人群相比，所有这些多态性的罕见等位基因频率较低，但与亚洲人群相比并非如此。AG H、I位点没有多态性。高度多态性位点之间存在连锁不平衡，其δ值表明：SP 24、27与AG C、G为0.68；SP 24、27与AG A1、D为0.71；XbaI与AG C、G为0.64；XbaI与AG A1、D为0.57；SP 24、27与XbaI为0.48；以及AG C、G与AG A1、D为0.68。基于六个位点（不包括启动子多态性）观察到了十种明确的单倍型，它们占样本的80%。由APOB基因所有位点的常见纯合子定义的单倍型SP27、G、A1、X-、I、T的频率为0.7，而在欧洲人中为0.22。祖先单倍型SP27、G、D、X-、I、T在奥朗阿斯利人和欧洲人中的频率都很低（0.01）。根据奥朗阿斯利人的单倍型构建的系统发育树显示了两条不同的进化路线，其他单倍型是由祖先单倍型的后续突变进化而来的。
