What types of biological evidence might contain mitochondrial DNA but not nuclear DNA?

Mitochondrial DNA (mtDNA) can be found in biological evidence such as hair shafts, bone, teeth, and certain types of soft tissue. These samples often contain mtDNA because mitochondria are present in many cells and are passed down maternally, while nuclear DNA may be degraded or absent. Additionally, forensic samples like degraded biological materials or those that lack cellular nuclei can still yield mtDNA for analysis.