So in the same way the code letters are formed in the Western scientific model of the genetic code, in the Eastern model two lines form a code letter.

Two unbroken lines would form Adenine.
Two broken lines would form Thymine.

A broken line below an unbroken line would form Guanine.
An unbroken line below a broken line would form Cytosine.

Three of these code letters combine to form the 64 hexagrams or "code-words."

Using the chart below the code-word UUU (which codes for the amino acid Phenylalanine) could also be expressed as 6 yin lines, or the figure to the left.

This figure is called hexagram 2, K'un, The Receptive in the I Ching.

Note the the hexagrams are always formed from bottom to top.

UGA, the code-word that tells the protein it is completed in the genetic code would form hexagram 12. P'i. Standstill

The correlations with the genetic code were made first in 1973 by Martin Schönberger in his book, The I Ching and the Genetic Code: The Hidden Key to Life.