Larkin Barbara, Iaschi Stephen, Dadour Ian, Tay Guan K
Centre for Forensic Science, The University of Western Australia, M420, 35 Stirling Highway, Crawley, WA 6009, Australia.
Forensic Sci Med Pathol. 2010 Jun;6(2):83-92. doi: 10.1007/s12024-009-9109-5. Epub 2009 Oct 23.
Determining the age of meat may require DNA extraction from tissue that may be frozen, chilled or sold over the counter of butchers. Until now, there has no systematic study on the ageing of meat. In the human application, the parallel is the determination of the time of death or postmortem interval (PMI). The purpose of this study was to investigate the effect of accumulated degree-days on the DNA yield of skeletal muscle and its possible application to estimate PMI. This study focused on the exposure of skeletal muscle tissue to a coastal environment. Two specimens of Sus domesticus, each weighing approximately 45 kg, were placed above ground to decompose over time. One pig was sampled over the summer season (December to February) and the other specimen during the winter season (June to August). Both the summer and winter pig studies were conducted in Drummond Cove, on the Mid West coast of Western Australia. Samples of muscle were collected at 2 day intervals for the summer and winter pigs. The daily maximum and minimum environmental temperature and humidity was recorded. Although time is an important factor in the degradation of DNA it is not critical. This study confirms that DNA degradation is best modelled as dependent on accumulated temperature rather than just time. The sequential nature and an initial decrease in the DNA yield in skeletal muscle has the potential to apply to estimation of PMI but further tests need to be conducted to confirm our findings.
确定肉的保存时间可能需要从可能已冷冻、冷藏或在肉店柜台出售的组织中提取DNA。到目前为止，尚未有关于肉保存时间的系统性研究。在人类应用中，与之类似的是确定死亡时间或死后间隔时间（PMI）。本研究的目的是调查累积度日对骨骼肌DNA产量的影响及其在估计PMI方面的可能应用。本研究聚焦于骨骼肌组织在沿海环境中的暴露情况。两只体重约45千克的家猪被放置在地面上，随着时间推移而分解。一头猪在夏季（12月至2月）进行采样，另一头猪在冬季（6月至8月）进行采样。夏季和冬季猪的研究均在西澳大利亚中西部海岸的德拉蒙德湾进行。夏季和冬季猪的肌肉样本每隔2天采集一次。记录每日的最高和最低环境温度及湿度。虽然时间是DNA降解的一个重要因素，但并非关键因素。本研究证实，DNA降解最好被模拟为依赖于累积温度而非仅仅是时间。骨骼肌中DNA产量的顺序性特征及最初的下降有可能应用于PMI的估计，但需要进一步测试以证实我们的发现。
