Santos M, Ward R H, Barrantes R
Sección de Genética Humana, Universidad de Costa Rica, San José.
Hum Biol. 1994 Dec;66(6):963-77.
The genetic variation in a Chibcha-speaking Amerindian tribe from lower Central America, the Huetar, was analyzed using nucleotide sequences of the hypervariable segments of the mitochondrial DNA (mtDNA) control region, the frequencies of 10 Amerindian-specific mtDNA haplotypes, and the regional distribution of private protein polymorphisms. The sequencing of 713 base pairs (bp) in the control regions of 27 individuals revealed 11 distinct lineages. These were defined by 24 variable sites and a 6-bp deletion between nucleotide pairs (np) 106 and 111. The 6-bp deletion is a new mtDNA marker that will be valuable for Amerindian taxonomic research. Control region sequences and mtDNA haplotype analyses reveal that Huetar mtDNAs are distributed in "Amerindian clusters" A, B, and D. A maximum-likelihood phylogenetic tree suggests a single origin for the 6-bp Huetar deletion in the sample. mtDNA haplotype analysis and the presence of previously characterized private protein variants (PEPAF, TFDCHI, and the absence of DI*A) show that the Huetar harbor polymorphisms of considerable antiquity, suggesting an early divergence from the regional founder gene pool for this population. The data also reflect a drastic constriction in population size, an evolutionary event with a proposed central effect on Huetar genetic structure.
利用线粒体DNA（mtDNA）控制区高变区的核苷酸序列、10种美洲印第安人特有的mtDNA单倍型频率以及私有蛋白质多态性的区域分布，对来自中美洲低地、说奇布查语的美洲印第安部落——胡埃塔尔人进行了基因变异分析。对27个个体控制区713个碱基对（bp）的测序揭示了11个不同的谱系。这些谱系由24个可变位点以及核苷酸对（np）106和111之间的一个6 bp缺失所定义。这个6 bp缺失是一个新的mtDNA标记，对美洲印第安分类学研究具有重要价值。控制区序列和mtDNA单倍型分析表明，胡埃塔尔人的mtDNA分布在“A”“B”和“D”这几个“美洲印第安人簇”中。一个最大似然系统发育树表明，样本中6 bp胡埃塔尔缺失有单一起源。mtDNA单倍型分析以及先前鉴定的私有蛋白质变体（PEPAF、TFDCHI以及DI*A的缺失）的存在表明，胡埃塔尔人拥有相当古老的多态性，这表明该群体与区域奠基基因库早期就发生了分化。数据还反映出种群规模的急剧收缩，这是一个对胡埃塔尔人基因结构有核心影响的进化事件。
