Ruth Padel

‘A ladder’, the master whispered, ‘of nucleic acid.’
This was the first we’d heard of it.
Rain nosed the glass; wind lashed the trees
outside. ‘Four hydrogen-bonded nucleotides
locking on like mating damselflies, but each
a different size, pulling the ladder’s sides
into a twist, like serpents on the sign
outside a chemist who for old time’s sake
gives lodging in his window to the alchemist’s
glass jars.’ He drew those twin snakes
looping up the wand
of God-Who-Escorts-Our-Morphia-Laden-Dead
to forest mist and shadowlands
where they belong, and brings them back
in dreams. ‘But one snake, the lagging strand,
is upside down.’ A squeak of chalk.
The pavilion, as I recall, was dark.
Rain pooled on the mesua floor.
‘We’re conflict from the start. One thread
runs easy. The other is fitful tickertape
on which genetic script, your soul’s barcode,
emerges opposite.’ What did we know?
We longed for a match, a cell phone, anything
that glowed. ‘As in a mirror, messages
are written here and must be read
backwards.’ We waited for the prayer
that never came. ‘Otherwise is built in.
Behold your molecule of heredity.
Two cosmic serpents, yes; but tail to head.’