Final answer:
To compare two hair samples, criminalists focus on matching DNA sequences using DNA isolation, sequencing, and analysis. Other microscopic characteristics of hair are also examined for differentiation.
Step-by-step explanation:
When a criminalist compares two hair samples, they are particularly interested in matching DNA sequences that may prove or disprove a connection to a particular individual. By analyzing the DNA content of the hair, forensic scientists can determine if there is an exact match to the DNA of a suspect, which is crucial evidence in a criminal investigation. This process usually involves DNA isolation, sequencing, and sequence analysis, with techniques such as polymerase chain reaction (PCR) amplification of short tandem repeat (STR) loci and electrophoresis. Other important features include the microscopic examination of the hair to look at characteristics like the medulla pattern, cuticle scale pattern, and pigment distribution that can help distinguish between different hair samples.