Hairs and fibers Differences Similarities: Both are… March 28 - 29 Trace evidence Class evidence - unless something really unusual Hard to see - Easy to miss at crime scene Collected with tape and tweezers Examined under microscope tube shaped usually round could be dyed easily shed - so lots of them around most common evidence at a crime scene could give DNA - (blood on fiber or root on hair) are made of non-living material don't have special storage requirements Differences fibers can be man-made fibers have no medulla, cuticle or cortex fibers have no internal structures hairs have pigment just in the center hairs have a scaly surface hairs can have a root hairs can have a pointed tip Hairs can give mitochondrial DNA hairs can indicate race some fibers don't stink when burned some fibers melt hair is always natural Hairs from the same person or animal are always different – there is variety all the fibers from the same garment will be identical unless damaged