Molecular analyses of the Peabody Basketmaker collection and their implications for Anasazi origins

在美国国家科学基金会的支持下，琼·布伦纳·科莱恩博士和肖恩·卡莱尔博士将分析来自美国西南部的一个人类埋葬标本的骨骼化学成分。 正在研究中的墓葬组成了“篮子匠收藏”，收藏在哈佛的皮博迪考古和民族学博物馆。 篮子制造者被认为是四角地区最早的农民，早于阿纳萨齐人，他们住在坑屋而不是土坯房，使用篮子而不是陶器。 皮博迪篮子制造者的收藏品是在世纪早期收集的，并没有像后来使用系统的挖掘和记录方法恢复的收藏品那样有很好的记录。 确定他们生活的时间框架，他们对玉米作为主食的依赖以及他们的遗传祖先将大大增加我们对西南史前这一重要时期的理解。 在这项研究中，我们将使用三种技术。 第一个是放射性碳测年。 这是通过从一小块骨头中分离和纯化一种称为胶原蛋白的蛋白质来实现的。 胶原蛋白构成骨骼的支撑框架，由含碳氨基酸组成。 这种碳的一小部分是碳的放射性同位素14C，使我们能够从骨胶原中获得放射性碳年代。 第二种技术是对篮子制造者饮食的两部分分析。 第一种是基于骨胶原中发现的两种稳定的碳同位素，13C和12C。 13C与12C的比例与采样个体饮食中的玉米量相关，并将在放射性碳测年中使用的相同分离和纯化的蛋白质上进行测量。 第二项检测将测量骨胶原中两种稳定的氮同位素15 N和14 N的比例，以估计我们的研究人群消耗了多少动物蛋白。 很有可能，当篮子制造者变得更加久坐不动，开始更加依赖玉米时，他们消耗的动物蛋白质减少了，这可能是动物猎物密度减少的结果。 最后，我们将从小块骨头中提取线粒体DNA，以确定篮子制造者与居住在南方的明布雷斯人，居住在北方的弗里蒙特人，在时间上追随篮子制造者的阿纳萨齐人以及现代美洲印第安人群体之间的遗传关系。 这将通过鉴定线粒体基因组中明显的特定母系谱系和对该基因组特定区域的DNA进行测序来实现。 从这些程序中获得的数据将有助于我们了解篮子制造者是谁，他们何时到达四角地区，以及他们随着时间的推移对玉米农业的依赖程度。 此外，同样重要的是，这些数据将使皮博迪博物馆能够遵守联邦立法（NAGPRA），该立法要求他们和所有管理美洲原住民遗骸的美国机构，如果要求，将这些遗骸归还或遣返给后代部落群体。 目前，有几个部落已经要求篮子制造商收集。 为了公平地归还这些收藏品，取决于所研究的遗传关系和时间框架。

With National Science Foundation support Drs. Joan Brenner Coltrain and Shawn Carlyle will analyze the bone chemistry of a human burial collection from the American Southwest. The burials under study make up the "Basketmaker Collection" and are housed at the Peabody Museum of Archaeology and Ethnology at Harvard. Basketmaker people are thought to represent the earliest farmers in the Four Corners region, predating the Anasazi, lived in pit houses rather than adobe structures and used basketry rather than pottery. The Peabody Basketmaker collection was assembled early in the twentieth century and is not as well documented as later collections recovered using systematic excavation and recording methods. Firmly establishing the timeframe in which they lived, their reliance on maize as a dietary staple and their genetic ancestry will add measurably to our understanding of this important period in Southwest prehistory. We will use three techniques in this study. The first is radiocarbon dating. This is accomplished by isolating and purifying a protein called collagen from a small piece of bone. Collagen makes up the supporting framework of bone and is comprised of amino acids that contain carbon. A small fraction of this carbon is the radioactive isotope of carbon, 14C, allowing us to obtain a radiocarbon date from bone collagen. The second technique is a two-part analysis of Basketmaker diets. The first is based on two stable isotopes of carbon found in bone collagen, 13C and 12C. The ratio of 13C to 12C covaries with the amount of maize in the diet of sampled individuals and will be measured on the same isolated and purified proteins that are used in radiocarbon dating. The second assay will measure the ratio of two stable isotopes of nitrogen in bone collagen, 15N and 14N, to estimate how much animal protein our study population consumed. It is very possible that as Basketmaker people became more sedentary and began to rely more heavily on maize, they consumed less animal protein, perhaps as a consequence of reduced animal prey densities. Finally, we will extract mitochondrial DNA from small pieces of bone to determine the genetic relationship between Basketmaker people and the Mimbres who lived to the south, the Fremont who lived to the north, the Anasazi who followed the Basketmaker in time and modern American Indian groups. This will be accomplished by identifying specific maternal lineages evident in the mitochondrial genome and by sequencing DNA in specific regions of that genome. The data from these procedures will improve our understanding of who the Basketmaker people were, when they arrived in the Four Corners region and how reliant they were on maize agriculture over time. In addition and of equal importance, these data will allow the Peabody Museum to comply with federal legislation (NAGPRA) that requires them, and all American institutions curating Native American remains, to return or repatriate these remains to descendent tribal groups if requested. Currently, several tribes have requested the Basketmaker collection. To equitably repatriate this collection is contingent upon the genetic relationships and temporal framework under study.