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developmental similarities between this phylumand chordates. Transcriptional and signallinggene expression patterns between the two groupsduring the early development of the anteroposteriorand dorsoventral axes reveal close similarities,despite large morphological disparity betweenthe body plans. These genetic networkshave been proposed to play conserved roles inpatterning centralized nervous systems in metazoans,yet seem to play a conserved role in patterningthe diffusely organized basiepithelialnerve net of the hemichordates. Developmentalgenetic data are providing a unique insight intoearly deuterostome evolution, revealing a complexityof genetic regulation previously attributedonly to vertebrates. While these data allowfor key insights into the development of earlydeuterostomes, their utility for reconstructingancestral morphologies is less certain, and morphological,palaeontological and molecular datasetsshould all be considered carefully whenspeculating about ancestral deuterostome features.2008040021环 境 和 挖 掘 : 实 验 室 之 前 对 古 DNA 分 析 的 影响 = Environment and excavation: Pre-lab impactson ancient DNA analyses. ( 英 文 ). BollonginoR; Tresset A; Vigne J-Da. ComptesRendus Palevol, 2008, 7(2/3): 91-98Ancient DNA (aDNA) analyses enjoy an increasingrole in palaeontological, archaeologicaland archaeozoological research. The limitingfactor for aDNA studies is the degree of DNApreservation. Our study on 291 prehistoric cattleremains from Europe, the Near East and NorthAfrica revealed that DNA preservation is mainlyinfluenced by geographic and climatic conditions.Especially in hot climates, the preservationof sample material is generally low. We observedthat these specimens are prone to furtherdegradation and contamination during and afterexcavation. We give a description of the maincaveats and a short guideline for adequate samplehandling in order to facilitate the cooperationbetween archaeologists and geneticists and toimprove the outcome of future research.2008040022家 畜 驯 化 的 古 遗 传 学 : 对 西 南 亚 驯 化 中 心 保存 的 化 石 骨 骼 研 究 的 方 法 论 挑 战 = Palaeogeneticsof cattle domestication: Methodologicalchallenges for the study of fossil bones preservedin the domestication centre in SouthwestAsia. ( 英 文 ). Geig E M. Comptes RendusPalevol, 2008, 7(2/3): 99-112Recently, palaeogenetics encountered enormoussuccess when parts of the nuclear genomesof mammoth and Neanderthal man were analysed.Their bones, however, had been preservedin environments favourable to DNA preservation,i.e., permafrost regions and caves in temperateregions. Few studies have tackled archaeologicalbones from hot, arid regions, although they beargreat significance for the study of evolution ofhumans and the precursors of modern societies.According to archaeological evidence, a keyevent in neolithisation, the domestication of cattle,took place around 10,000 years ago inSouthwest Asia. Genetic data from prehistoricbovine bones preserved in this region might shedlight on this process, but the palaeogenetic approachhas been hampered by poor DNA preservation.Here, I discuss various aspects of DNApreservation in fossils and the production of reliablepalaeogenetic data and present methodologicalimprovements that have enabled us toshed light on the process of cattle domesticationin Southwest Asia and its spread into westernEurope.2008040023从 化 石 骨 骼 中 遗 迹 组 分 的 分 布 比 较 重 结 晶 速率 与 生 物 分 子 的 保 存 潜 力 = Comparing ratesof recrystallisation and the potential for preservationof biomolecules from the distribution oftrace elements in fossil bones. ( 英 文 ). TruemanC N; Palmer R M; Field J; Privat K; Ludgate N;Chavagnac V. Comptes Rendus Palevol, 2008,7(2/3): 145-158Preservation of intact macromolecules andgeochemical signals in fossil bones is mainlycontrolled by the extent of post-mortem interactionbetween bones and sediment pore waters.Trace elements such as lanthanum are added tobone post-mortem from pore waters, and whereuptake occurs via a simple process of diffusionand adsorption, the elemental distribution can beused to assess the relative extent of bone-porewater interaction and rate of recrystallisation.Distribution profiles can be parameterised effectivelyusing simple exponential equations, andthe extent of bone–water interaction comparedwithin and between sites. In this study, the distributionof lanthanum within bone was determinedby laser ablation ICP–MS in 60 archaeologicaland fossil bones from Pleistocene andCretaceous sites. The rates of recrystallisationand potential for preservation of intact biogeochemicalsignals vary significantly within andbetween sites. Elemental profiles within fossilbones hold promise as a screening technique toprospect for intact biomolecules and as a taphonomictool.古 生 态 学20080400247