tna

As a noun taxonomy

is the science or the technique used to make a classification.

As an initialism tna is

(biochemistry) threose nucleic acid or threonucleic acid.

Tna is a hyponym of xna.

In biochemistry|lang=en terms the difference between tna and xna

is that tna is (biochemistry) threose nucleic acid or threonucleic acid while xna is (biochemistry) nucleic acid analogue (nucleic acid analog) ; (backformation) ; x nucleic acid, where "x" is a stand-in for multitude of various nucleic acid acronyms, which are not dna or rna.

As initialisms the difference between tna and xna

is that tna is (biochemistry) threose nucleic acid or threonucleic acid while xna is (internet).

As a noun xna is

(biochemistry) nucleic acid analogue (nucleic acid analog) ; (backformation) ; x nucleic acid, where "x" is a stand-in for multitude of various nucleic acid acronyms, which are not dna or rna.