4. What challenges do you think giving expert testimony about DNA would have? How would you try to overcome these challenges?

Contamination, errors introduced in the artificial replication process, statistical inference, and finally source. There was a case in the UK recently where a persons DNA was at a crime scene, but it was eventually determined that his DNA made it there via transference. The original suspect was a cab driver and the actual perp had been in the cab shortly before the crime.