ABSTRACT
The extraction of nucleic acids from hard tissues has always been considered challenging. Methods need to meet the requirements of disrupting tissue such that nucleic acids are released, without inducing or exacerbating nucleic acid degradation, or copurifying inhibitors of subsequent enzyme-catalyzed reactions [1]. In addition, tissues such as bone harbor comparatively low levels of endogenous nucleic acid due to their low cellularity, and may include greater amounts of exogenous microbial or fungal DNA [2]. There are however fundamental differences in the types of applications
where DNA or RNA would be extracted from these tissues, which produce challenges specifi c to each type of extraction. Where RNA is being sought from hard tissues, this is because the study is focusing upon the biology of the tissues in question, and in such studies the tissues will have been deliberately chosen. This choice implies some degree of control over sample conditions, which greatly facilitates the extraction of labile RNA molecules. In contrast, where DNA is extracted from hard tissues, this is rarely an issue of choice, but instead refl ects that more accessible tissues (Chapters 16 and 17) are not or no longer available. This means that the hard tissue samples commonly used for DNA extraction present additional challenges, through being aged, environmentally exposed or contaminated, available in limited quantity, or through being available in large numbers, with none of these parameters necessarily refl ecting the choice of the investigators.
