MITOCHONDRIAL GENES AND AMERINDIAN ORIGINS

据推测，美洲原住民是从亚洲来的 三个独立的迁徙：占领南部、中部的古印第安人 和北美洲；加拿大西北部和阿拉斯加的纳德涅；以及 生活在北极的爱斯基摩人和阿留申人。为了检验这一假设，我们正在 分析美洲印第安人线粒体DNA(MtDNA)序列变异， 亚洲人和西伯利亚人经聚合酶链式反应扩增、消化 具有多个限制性内切酶和D-loop测序。线粒体DNA 然后通过系统发育分析比较种群的变异和 通过计算遗传距离(D[XY])和种群亚结构 (GST)。这些研究表明，古印第安人携带四种线粒体DNA。 之间到达美洲的血统(单倍型簇A-D) 距今23,000年和46,000年前(YBP)一次或两次迁移。这个 NA-Dene代表一个线粒体DNA谱系(集群)的后续迁移 A*)，抵达约6,000至12,000(YBP)。 我们建议将我们的mtDNA研究扩展到(1)确定是否存在 两次古印度迁移，(2)证实了纳德尼的均质性 移民，(3)确定是否有明显的爱斯基摩-阿留申移民， (4)寻找美洲印第安人的亚洲或西伯利亚祖先 迁移和(5)改进我们对迁移时间的估计。为了测试 对于两次古印第安人迁徙，来自北部、中部和中部的23个古印第安人部落 将对南美地区进行筛查，以寻找不均匀分布的 单倍型聚类A-D，并确认单倍型的初步数据 星团B比其他星团更年轻。Na-Dene的均质性 移民将通过显示额外的阿拉斯加和加拿大人得到确认 Na-Dene mtDNA属于单倍型簇A*，年龄相同。这个 爱斯基摩人和阿留申人与古印第安人和纳德尼人的关系 将通过收集爱斯基摩人和阿留申人的样本进行检查 并测定了它们的mtDNA单倍型和序列变异。这个 将通过筛选12名亚洲人和西伯利亚人来寻找美洲印第安人的起源 已知与每个基因相关的线粒体DNA变异的群体 美洲印第安人的迁徙及亚洲-西伯利亚和美洲印第安人序列分析 同源。迁徙的年龄将通过减去

It has been hypothesized that Native Americans arrived from Asia in three separate migrations: the Paleo-Indians which occupy South, Central and North America; the Na-Dene of northwestern Canada and Alaska; and the Eskimos and Aleuts of the Arctic. To test this hypothesis, we are analyzing the mitochondrial DNA (mtDNA) sequence variation of Amerindians, Asians and Siberians by polymerase chain reaction amplification, digestion with multiple restriction endonucleases and D-loop sequencing. The mtDNA variation of the populations is then compared by phylogenetic analysis and by calculation of genetic distances (D[xy]) and population substructures (GST). These studies have revealed that Paleo-Indians harbor four mtDNA lineages (haplotype clusters A-D) which arrived in the Americas between 23,000 and 46,000 years before present (YBP) in one or two migrations. The Na-Dene represent a subsequent migration baring one mtDNA lineage (Cluster A*) which arrived about 6,000 to 12,000 (YBP). We propose to extend our mtDNA studies to (1) determine if there were two Paleo-Indian migrations, (2) confirm the homogeneity of the Na-Dene migration, (3) determine if there was a distinct Eskimo-Aleut migration, (4) search for the Asian or Siberian progenitors of the Amerindian migrations and (5) refine our estimates of the migration times. To test for two Paleo-Indian migrations, 23 Paleo-Indian tribes from North, Central and South America will be screened for a non-uniform distribution of haplotype clusters A-D and to confirm preliminary data that haplotype cluster B is younger than the others. The homogeneity of the Na-Dene migration will be confirmed by showing that additional Alaskan and Canadian Na-Dene mtDNAs belong to the haplotype cluster A* and are of same age. The relationship of the Eskimos and Aleuts to the Paleo-Indians and Na-Dene will be examined by collecting Eskimo and Aleut samples throughout the arctic and determining their mtDNA haplotypes and sequence variation. The origins of Amerindians will be sought by screening 12 Asian and Siberian populations for the mtDNA variants known to be associated with each Amerindian migration and analysis of Asian-Siberian and Amerindian sequence homologies. The age of the migrations will be refined by subtracting