Sequence homology: Dog: 100%; Horse: 100%; Human: 100%; Mouse: 100%; Pig: 100%; Rat: 100%; Zebrafish: 93%. Involved in the biosynthesis of ganglioside GD1A from GM1B. Transfers CMP-NeuAc with an alpha-2,6-linkage to GalNAc residue on NeuAc-alpha-2,3-Gal-