古人类对赭石的利用行为在其演化中的意义

长期以来赭石利用行为被视为人类行为现代性的标志之一,受到国内外考古学界的普遍关注。本文回溯和梳理了全球背景下赭石利用的起源、发展及其与人类演化史的关系。在现代人广泛分布于全球之后,赭石利用行为更加丰富和多样化地出现在各地,然而现有考古证据表明该行为并不是解剖学意义上的现代人突变性的发明。赭石利用不能被单纯地定义为现代人行为,而应是有着长久演化积累的现代性行为之一。在长期传播与演化过程中,赭石的功能从意识形态、艺术表达等逐渐扩展到作为矿物成分被用于实际生产生活。赭石的利用历史可追溯到中更新世中期,但其广泛分布仍与晚更新世以来现代人的广泛扩散直接相关,对于理解现代人的意识形态、社会组织方式以及艺术表达、精神文化发展都具有重要的意义。国内目前所发表的相关考古学证据相对较少,以下马碑遗址为代表的材料,也恰处于现代人在全球广泛扩散的窗口期,并伴有进步的细小石器镶嵌使用的证据,成为认识东亚现代人行为的关键性考古证据。     

Mutagenesis and mutation transfer induced by ultraviolet light in plasmid-cloned DNA

We describe here simple techniques for increasing the frequency of UV-induced mutations in a DNA fragment cloned in plasmid pBR322. Irradiation of both the host and the plasmid DNA before transformation is necessary to produce new mutations in the plasmid DNA, presumably because the UV-damaged pBR322 replicon cannot efficiently induce the error-prone repair pathway of Escherichia coli. In contrast, U V irradiation of the plasmid DNA alone before transformation primarily causes the transfer of preexisting mutations from the host chromosome to homologous DNA present in the plasmid. The only other kind of mutants obtained were large deletions of the plasmid DNA. Two chromosomal mutations from the host galK gene and one from the lacZ gene have been transferred to the plasmid by UV irradiation of the plasmid DNA alone. The technique can thus be of general use.     

Prophage lambda at unusual chromosomal locations. II. Mutations induced by bacteriophage lambda in Escherichia coli K12

An Escherichia coli strain deleted for the primary λ attachment site was lysogenized with λ at secondary sites. Some lysogens became mutants because of prophage insertion in the affected gene. Mutagenesis by phage λ is not random with respect to the gene affected: most mutants were pro, although certain other genes could be mutated at lower frequencies. In the case of several independent ilv and gal mutants, the sites of prophage insertion were in the same segment of the ilv region and galT gene respectively. The galT location may also be a preferred site for the insertion of DNAs other than prophage λ. Insertion of prophage λ within an operon can reduce the expression of operator-distal genes. A trpC λ insertion mutant expresses the operator-distal trpB function constitutively at a low level. This expression probably derives from a promoter located in the left arm of the prophage.     

Emergence of a mutagenic ochre suppressor mutation under lactose selection in appm mutant ofEscherichia coli harbouring the F′lacZU118 episome

WhenEscherichia coli harbouring theppm (earlier calledadi) mutation and the F′lacZU118 episome is subjected to lactose selection in the presence of suboptimal concentrations of glycerol, Lac⁺ colonies emerge after 5–6 days. They are shown to harbour an ochre suppressor mutation at 15.15 min. Inactivation ofrecA results in approximately four-fold reduction in the response. In theppm — ochre suppressor double mutant background the leakiness of thelacZ allele carried by F′ CC105 is enhanced, suggesting misreading of a valine codon (GUG) as glutamic acid codon (GAG). This is accompanied by reversion of thelacZ mutation tolacZ ⁺ (GTG → GAG). In LB medium both the leakiness and reversion are inhibited by streptomycin. Inactivation ofrecA did not affect leakiness but abolished reversion. These data are discussed in relation to the importance of allele leakiness and restricted growth in stationary-phase (adaptive) mutagenesis.     

Putting ochre to the test: replication studies of adhesives that may have been used for hafting tools in the Middle Stone Age

Substantial frequencies of Middle Stone Age (MSA) lithics from Rose Cottage and Sibudu Caves in South Africa have red ochre on their proximal and medial portions. Residue studies suggest that the tools were hafted and that the ochre may be part of the adhesive used for hafting the tools. Replication studies show that ochre is indeed a useful loading agent for adhesive; however, there are other potential loading agents. It is also possible to use unloaded plant resin, but this agent is brittle and difficult to work with. It appears that people living in the MSA had wide knowledge of ingredients suitable for hafting tools, and that they chose different adhesive recipes because of the required properties of the adhesive. Brittle, unloaded adhesive allows a projectile head to disengage its haft and implant itself in an animal; robust adhesive keeps a spearhead safely in its shaft.     

四川资阳人遗址出土的骨锥

四川资阳人遗址因人类头骨化石的发现而备受关注,但该遗址1951年出土的唯一一件有机质工具——骨锥却鲜被提及。该骨锥长度约为10 cm,距今超过7500年。本文利用体视显微镜、扫描电镜能谱和激光元素仪等技术手段,对这件骨锥的形态、原料选择、制作技术、使用与废弃过程及锥尖部的红色残留物进行了观察分析。研究结果显示,骨锥的制作原料取自大型鹿类胫骨骨干;主要采用刮削技术制作而成,但刮削痕迹并不规整,推测制作者更侧重器型的规整和对称;锥尖部的磨圆、抛光和横向擦痕可能是穿孔过程中产生的,其工作对象主要应为兽皮等软性材料。值得注意的是,锥尖部还发现有赭石粉末残余,表明当时的人类已经掌握了利用赭石处理皮毛及缝制衣物的技术。资阳骨锥应是中国史前规范骨器中一器多用的典型例证,也是中国首次发现的沾染赭石的有机质工具。