We are used to drugs synthetic
Manmade textiles we can wear,
But with living alphabetics
We have, so far, not playing dared...
A and C and G and T
Are four letters of all life,
No one knows why this should be,
Why not seven. six, or five?
To fashion words, DNA's decree
Life quite rigidly abides:
Pairs of AT and CG
Appear always side by side.
Now scientists with nature played,
Adding XY to the pairs,
And squeezed them into the DNA
Of a bacterium, with great care.
New proteins for cells to replicate
Were now created in this way,
Causing some folks to speculate
What dangers lurked in this assay?
But the new code only survived
For generations three or four.
Perhaps there is good reason why,
We have four bases, never more...