Source: arXiv:1106.4192v1
Very interesting information presented in this source. I was not aware that the human genome database contains mycoplasma expressed sequence tags. The source is mould which infects microbiology laboratories. This contaminates samples and is treated as human DNA. The error enters GenBank, where companies use this data to design DNA microarrays. Microarrays are often used in medicine to measure gene expression and for single nucleotide polymorphism detection.