Origins Page 86

precision, from the large structures of wings, fins, bones, muscles, and organs to the microscopic machinery operating within their cells.

DNA: The Genetic Blueprint of Life

Within the cells of every living creature is DNA, the remarkable information-bearing molecule carrying the genetic instructions required for life.   Along its long molecular strands, sequences of four chemical bases form genes and regulatory regions that direct the construction, maintenance, function, and reproduction of the organism.

The vast array of genetic information that is encoded within this DNA double helix provides the instructions used by living cells.  These instructions enable cells to produce proteins, control metabolic functions and biological processes, build, maintain, and repair tissues and organs, and coordinate the countless activities required to sustain life.

DNA Directs Biological Form and Function

From the formation of feathers and wings in birds to fins, scales, muscles, skeletal structures, sensory organs, and nervous systems in aquatic creatures, DNA provides the genetic instructions required to build these extraordinarily sophisticated biological structures.  Its vast storehouse of encoded information also helps direct the formation and operation of the many complex internal systems required for the living body to function as an integrated whole.

Billions of Units of Genetic Information

Many animal genomes contain billions of DNA base pairs, forming immense sequences of encoded genetic information.  Within this vast storehouse of information are thousands of protein-coding genes, together with many thousands of regulatory sequences that help

determine when, where, and how those genes are used.  These sequences contain an extraordinary quantity of biological information, organized within the DNA molecules packed into the cells of the living organism.