Department of Ecology and Evolutionary Biology, University of California Los Angeles, California 90095.
The George C. Page Museum of La Brea Discoveries 5801 Wilshire Boulevard, Los Angeles, California 90036.
Ecol Evol. 2014 Feb;4(4):329-36. doi: 10.1002/ece3.928. Epub 2014 Jan 11.
Fossil-bearing asphalt deposits are an understudied and potentially significant source of ancient DNA. Previous attempts to extract DNA from skeletons preserved at the Rancho La Brea tar pits in Los Angeles, California, have proven unsuccessful, but it is unclear whether this is due to a lack of endogenous DNA, or if the problem is caused by asphalt-mediated inhibition. In an attempt to test these hypotheses, a recently recovered Columbian mammoth (Mammuthus columbi) skeleton with an unusual pattern of asphalt impregnation was studied. Ultimately, none of the bone samples tested successfully amplified M. columbi DNA. Our work suggests that reagents typically used to remove asphalt from ancient samples also inhibit DNA extraction. Ultimately, we conclude that the probability of recovering ancient DNA from fossils in asphalt deposits is strongly (perhaps fatally) hindered by the organic compounds that permeate the bones and that at the Rancho La Brea tar pits, environmental conditions might not have been ideal for the general preservation of genetic material.
含化石的沥青矿床是一个研究不足但具有潜在重要意义的古代 DNA 来源。此前，从加利福尼亚州洛杉矶的拉布雷亚沥青坑中保存的骨骼中提取 DNA 的尝试均未成功，但尚不清楚这是由于缺乏内源性 DNA，还是由于沥青的抑制作用所致。为了验证这些假说，研究了一具最近发现的哥伦比亚猛犸象（Mammuthus columbi）骨骼，其具有不寻常的沥青浸渍模式。最终，没有一个骨样本成功扩增了 M. columbi 的 DNA。我们的工作表明，通常用于从古代样本中去除沥青的试剂也会抑制 DNA 提取。最终，我们得出结论，从沥青矿床中的化石中回收古代 DNA 的可能性受到渗透到骨骼中的有机化合物的强烈（也许是致命）阻碍，而且在拉布雷亚沥青坑，环境条件可能不利于遗传物质的一般保存。
