Hair samples should ideally be stored under which condition for long-term preservation?

Storing hair samples under temperature-controlled conditions is essential for long-term preservation as it helps maintain their integrity and prevents degradation over time. This method allows for a consistent environment that mitigates the effects of temperature fluctuations, humidity, and potential contamination, which can occur in uncontrolled storage situations.

Temperature-controlled conditions ensure that hair samples are kept at optimal temperatures, protecting them from heat which can deteriorate the sample and from cold that might cause moisture buildup when thawing, both of which could compromise the quality of the evidence.

In contrast, while drying and refrigeration can be beneficial for short-term storage, they do not provide the same level of comprehensive protection as temperature control across a range of environmental factors, making them less suitable for long-term preservation. Freezing may also pose risks such as cell damage or alteration upon thawing, highlighting the importance of maintaining a steady controlled temperature instead.