HIV-1 mutates rapidly. Based on this, would you expect to find a single, identical sequence in the victim and the patient, or would you expect to find a set of related sequences that share a common ancestor? Explain your answer.
Additional Requirements
Other Requirements: Part II - Circumstantial Evidence
Other possible sources of the infection included the woman's prior sexual contacts and occupational exposure, given that she was a nurse.
All seven of the men that she had been in sexual contact with (including her former boyfriend) were tested and found to be HIV-negative.
Her employment records were examined, and there were no reports of any accidental or occupational exposures other than the saliva that was splashed on her skin sometime in the mid-1980s. Her file did not have any documentation of any needle sticks at work.
As the investigation proceeded, it was found that an HIV-positive patient under the care of the ex-boyfriend/doctor had blood drawn at the physician's offices on August 4, 1994. The paperwork for this procedure was deliberately hidden (the log book was found in a box of "1982 records" in a storage room with other records from the 1980s) and was not filled out in a manner that was consistent with standard office practices.
Based on the circumstantial case against the physician, the reverse transcriptase (RT) sequences from the victim (the nurse/ex-girlfriend) and from the physician's HIV-positive patient (the putative source of the nurse's infection via the injection administered during the ill-fated argument) were analyzed. The reverse transcriptase (pol) gene was used in the actual criminal trial. Reverse transcriptase has a unique set of selective pressures exerted on it and is therefore a useful gene/protein to explore in order to establish relationships between different strains of HIV.