Cover Story | Human genetic material is organized into 23 pairs of chromosomes,
each composed of protein molecules and one long strand of DNA. The
chromosomes are in distinct pairs only when the cell is dividing;
the rest of the time they form a tangled ball called the genome. A
gene is a section of a DNA strand that "encodes for" or makes the
proteins that determine how the cell develops and functions.
"Introns," sections of DNA that either apparently do not have a
function or whose function is