DNA analysis initially used blood samples, later and now commonly a buccal (cheek) or saliva sample. DNA is also now recovered from hair and ancient bones. An article, Using FastID to analyze complex SNP mixtures from indoor dust , describes a study that used single nucleotide polymorphisms (SNPs) and massively parallel sequencing (MPS) to analyze human DNA from indoor dust samples.
Samples of dust from five locations in a house were compared with buccal samples. They found that 93% of known occupants were detected in at least one dust sample. Non-occupant alleles were present in 54% of dust samples. They concluded that analyzing SNPs from indoor dust could be a potential forensic tool to identify past presence of individuals and envisaged the technique being used for investigative leads, to refute a suspect’s alibi, or link a suspect with a crime scene.
In genetic genealogy one can imagine taking an ancestor’s old dusty album, stored away for decades, yielding dust that could be analysed to reveal their DNA profile. It might be possible to trace their ancestry and physical characteristics based on their SNPs.
Technical challenges remain, such as the degradation, contamination, and complexity of the DNA mixtures in the dust samples, as well as ethical and legal issues.