Temporal rate of postmortem DNA degradation in archived tissue samples: evidence from liver and muscle
Temporal rate of postmortem DNA degradation in archived tissue samples: evidence from liver and muscle
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DOI：
10.1093/jmammal/gyac089
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发表时间：
2022-10-27
影响因子：
1.7
通讯作者：
Bradley, Robert D.
中科院分区：
文献类型：
--
作者：
Amarilla-Stevens, Heidi N.;Stevens, Richard D.;Bradley, Robert D.
确定收获组织的最佳做法以实现最佳DNA保存的指南很少，但对于遗传资源收集来说，这是一个重要的管理问题。我们进行了一项时间研究，以确定从野外捕获的博物馆标本中提取的组织样本的DNA降解率。本研究采集了5只刚毛对虾的个体，并采集其肝脏和肌肉组织。每种组织类型被分成15个亚样，每个亚样在死亡后不同的时间间隔(2、4、8、16和32min；1、2、4、8和16h；以及1、2、4、8和16天)被保存在液氮中。使用自动机器人仪器提取DNA，并用荧光法测定分子质量分布。死后DNA的降解是连续的，依赖于时间，但也受到棉鼠个体差异的显著影响。在所有时间间隔的肌肉样本中都存在长度为>；=10,000碱基对的DNA片段，而在死后8-16小时后，肝脏样本中不再存在这种大小的DNA片段。DNA分子质量图谱显示，直到死后1天，肌肉样本保留了80%的最长片段(~gt；=10,000碱基对)，而肝脏样本仅在死亡后8分钟保持了相同的百分比。虽然腐烂率是在实验室(而不是野外)环境中从样品中测量的，但这里提供的腐蚀率可以指导野外和博物馆工作人员进行最佳实践。结果表明，当肌肉被保存下来时，机会主义的样本，如那些来自被撞死的样本的样本，更有可能用于各种分子方法。考虑到降解率的差异也可以指导遗传资源收藏中组织类型的选择，特别是在空间有限的情况下。
Guidelines identifying best practices for harvesting tissues that lead to optimal DNA preservation are few but are important curatorial concerns for genetic resource collections. We conducted a temporal study to establish rate of DNA degradation of tissue samples extracted from field-caught museum specimens. Five individuals of Sigmodon hispidus were collected and their liver and muscle tissues were harvested. Each tissue type was sectioned into 15 subsamples, and each was preserved in liquid nitrogen at different time intervals (2, 4, 8, 16, and 32 min; 1, 2, 4, 8, and 16 h; and 1, 2, 4, 8, and 16 days) following death. DNA was extracted using an automated robotic instrument and molecular mass profiles were determined fluorometrically. Postmortem DNA degradation was continuous and dependent on time, but also was significantly affected by differences among individual cotton rats. DNA fragments of >= 10,000 base pairs in length were present in muscle samples across all time intervals, whereas DNA fragments of this size in liver samples were no longer present after 8-16 h postmortem. DNA molecular mass profiles showed that muscle samples retained 80% of their longest fragments (>= 10,000 base pairs) until 1 day postmortem, whereas liver samples retained the same percentage only until 8 min after death. Although rates of decay were measured from samples in a laboratory (not field) setting, rates of decay presented here can guide field and museum workers in best practices. Results suggest that opportunistic samples, such as those from roadkill specimens, are more likely to be of use for a variety of molecular methods when muscle is preserved. Considerations of differences in rates of degradation may also guide selection of tissue types housed in genetic resource collections, especially under space-limited circumstances.