to see pigment distribution. Investigators also examine the outer sheath, called the
which grows in overlapping scales. Some hairs have a visible inner shaft, called a
. In other
hairs, the medulla appears cracked or
or they have no medulla.
Each cell in the body contains
, which is shaped like a twisted ladder with rungs.
sequence of the
is unique for each individual.
Scientists can remove DNA from body
and fluids and make it key segments of it visible on x-ray film.
produced in the films can positively link a suspect to DNA from a crime scene or exclude a
suspect. DNA evidence was able to exclude an ex-boyfriend as well as the suspect, which
Forensic scientists and scholars can study a painting to determine if it is
or a forgery. A forensic scientist can try to determine the painting's age by taking
samples of the
and placing them on a microscope slide.
Each color is made from a different
mineral or vegetable base and gives it a unique appearance under a polarizing light
Investigators can also analyze the
, which is a substance that suspends the pigment
and allows painters to use it on a canvas.
The most common medium is
Leonardo da Vinci also used
Samples of the canvas can be removed for
to reveal the age of the canvas
The test results could not rule out the possibility that the painting was created by Leonardo
da Vinci, so the painting's owner turned to
to help him.
The scholars noticed the
in Christ's wrist, which DaVinci did in his paintings.