So What Did Margie Say About...

 

A piece of crucial evidence in the 3/6/13 CSI: Crime Scene Investigation episode titled "Karma to Burn" was a plaster piece with segments of hair.  It made me think of how far evidence has come over the years.

 

    There are basically two types of evidence: individualistic and class.  The individualistic is obviously something that is unique and can bring significance to a piece of evidence and tie it to a source.  Class evidence places an item of evidence into a group, not as specific as individual.

 

    Hair used to be viewed first visually and then came the microscopic examination.  Some questions may have been asked and potentially answered by these inspections.  How long is it?  What color is it?  Had it been dyed?  Had it been forcibly removed?  Had it been cut?  Had it been damaged in any way?  What species is it (meaning was it animal or human)?  What part of the body did it originate from if it was human?

 

    Characteristics like the medulla were compared.  If you think of a hair like a lead pencil, the medulla is the lead center.  The cortex and cuticle are other characteristics that could be telling.  The cortex is the wooden part of the pencil which in the hair may contain the pigment.  The outer layer is the cuticle and looks like scales on a fish.

 

    Samples from at least four or five areas of the head hair were collected for comparison as there are variances to the hair samples from each person.  Some have course hairs, some have grey hairs, everyone has variances in the shades of their hair color, etc.

 

    However these observations were class characteristics.  Nothing as substantial as the data that you can get from the DNA analysis from the root from a hair. 

 

    But hairs which fall out naturally may not exhibit a root which would contain the cellular nucleus DNA material.  Even so, the days of the microscopic examination for hairs is long gone or almost gone for most crime laboratories.  It is thought to be too time consuming for such 'insignificant' information.

 

    Let's not tell that to the producers though.  The hairs were examined microscopically and found to be bovine.  This eventually became crucial information.  Hooray for the good old days, huh?