I. D. Lecce, J. Sudyka, D. F. Westneat, und M. Szulkin, „Preserving avian blood and DNA sampled in the wild: A survey of personal experiences“, Ecol. Evol., Bd. 12, Nr. 8, S. e9232, Aug. 2022, doi: 10.1002/ece3.9232.
LEA – Storage conditions is a key issues
Researchers are able to reliably conduct a variety of analyses on biological material from wild populations thanks to the wide range of low-cost molecular tools that are currently available and the increasing computational power that is able to handle large amounts of data. However, the conditions under which samples are stored continue to be a major problem that can make it difficult to generate high-quality genetic data from animal tissues or blood. A well-informed decision regarding sample preservation must be made during the logistical planning phase of a long-term study. Nucleic acids may break down as a result of inadequate preservation, which could compromise the quality of the samples and the scope of the research. Therefore, temperature and the method of storage are essential components of sample preservation.
Method of storage
For long-term storage, direct sample freezing is regarded as the preferred method. Compared to freezing, other methods of storage that require a liquid preservative or physical support may offer advantages. There is also evidence that the storage method has a significant impact on the measurements of relative telomere length (RTL).
´Recommendations
Lower storage temperature is effective for reservation
Because the nuclei of avian red blood cells were thought to be metabolically inactive, storage at a temperature of -20°C was considered sufficient to prevent DNA degradation when directly freezing samples at temperatures as low as -80°C. Even at a lower storage temperature, freezing at -20°C may still provide better preservation conditions.is not possible because the samples are kept at room temperature. However, numerous studies have shown that DNA extracted from whole blood samples kept at room temperature has poor stability, while DNA yields from samples +4°C or lower are better.
Additional factors influencing sample stability
Scientists‘ long-term blood and DNA storage experiences may shed light on how frequently issues with sample collection or storage can affect DNA quality. After ten months of storage in EDTA, blood samples had significantly lower yields for DNA extraction and higher levels of methylation.
´Survey
Observation of the experiments
A survey conducted online titled „Preserving avian DNA from the wild: On the Survey Monkey platform, the article titled „Your experience with blood sampling, DNA extraction, and storage“ was created. Three sections: DNA, blood sample collection, and blood storage the survey was distributed from the summer of 2018 to the beginning of the spring of 2019, specifically aimed at evolutionary, ecological, and conservation biology researchers who work with wild birds. And at conferences like the International Ornithological Congress 2018 and the International Society for Behavioral Ecology 2018, as well as via email to more than 500 researchers who work with wild birds outside of North America and Europe. These researchers were found through searches on the Web of Science.
Data analysis
Between issues with adequate DNA quality or quantity and issues with inadequate storage (yes/no).A yes/no variable was used to code problems. Storage methods for blood samples (yes or no) or DNA extracts (yes or no) to determine which storage methods were more likely to be associated with DNA quantity and quality.
Result
The experience of respondents in field blood sampling was surveyed across 53 nations and territories. The most popular storage options for samples were filter paper, ethanol, lysis buffer, direct freezing, and ethanol. In the remaining 16% (44/266) of cases, TE buffer, RNA later and other mediums was utilized. From the 170 responses to the question, „How long do you typically perform analyses after DNA extraction? “The category „Other“ in (c), which included: PBS, EDTA, and lysis buffer. The researchers‘ storage issue was described in 44 open responses.