An example of simile used in popular science writing,
"DNA is formed of two strands joined together via pairs of bases. We could visualise this as looking a little like a railway track. The two rails are held together by a base on one rail linking to a base on the other side, as if the bases were holding hands. They only link up in a set pattern. T holds hands with A, C holds hands with G."
Nessa Carey (2015) Junk DNA. A journey through the dark matter of the genome. London: Icon Books Ltd.
Read about examples of science similes
Of themselves, the statements that "T holds hands with A [and] C holds hands with G" can be seen as metaphors (where the reader has to appreciate that a figure of speech is being used), but this idea has already been introduced marked as a comparison in the simile ("as if the bases were holding hands").
