蓝藻模型
科学家们认为，在地球的主要遗传物质DNA（脱氧核糖核酸）到来之前，早期生命利用RNA（核糖核酸）编码遗传指令。那么，在RNA之前，生命又是依赖什么样的遗传分子？答案或许就是AEG。
AEG是一种小分子物质，这个小分子连接成链时可为肽核酸构建一个骨干，而肽核酸被假定为生命的第一个遗传分子。制药业一直将合成AEG作为可能的基因静默者开展研究，用以阻止或减缓某些遗传性疾病。到现在为止，此一理论的唯一问题是，一直无法在自然界中发现AEG。
11月9日，美国和瑞典的科学家团队在《公共科学图书馆·综合》上发表论文宣布，他们已经在地球上最原始的生物蓝藻细菌中发现了AEG。蓝藻细菌常常以浮沫的形式出现在炎热夏季的水库和湖泊表面，它们对极端生境具有极强的耐受性。
为了确定蓝藻细菌产生AEG的广泛性，科学家们分析了法国巴士德藻种库保存的原始蓝藻细菌培养物。他们还收集了来自美国关岛、日本、卡塔尔以及蒙古戈壁沙漠中的蓝藻细菌样本。美瑞两国科学家对相同样本进行研究后，得出了相同的结果：蓝藻细菌可产生AEG。
Cyanobacteria Produce N-(2-Aminoethyl)Glycine, a Backbone for Peptide Nucleic Acids Which May Have Been the First Genetic Molecules for Life on Earth
Sandra Anne Banack, James S. Metcalf, Liying Jiang, Derek Craighead, Leopold L. Ilag, Paul Alan Cox
Prior to the evolution of DNA-based organisms on earth over 3.5 billion years ago it is hypothesized that RNA was the primary genetic molecule. Before RNA-based organisms arose, peptide nucleic acids may have been used to transmit genetic information by the earliest forms of life on earth. We discovered that cyanobacteria produce N-(2-aminoethyl)glycine (AEG), a backbone for peptide nucleic acids. We detected AEG in axenic strains of cyanobacteria with an average concentration of 1 µg/g. We also detected AEG in environmental samples of cyanobacteria as both a free or weakly bound molecule and a tightly bound form released by acid hydrolysis, at concentrations ranging from not detected to 34 µg/g. The production of AEG by diverse taxa of cyanobacteria suggests that AEG may be a primitive feature which arose early in the evolution of life on earth.
