The mouse assembly GRCm38 (GCA_000001635.2) was submitted by the Genome Reference Consortium (GRC). The whole assembly comprises 65 toplevel sequences: 19 autosomes, X and Y, 22 unlocalized scaffolds and 22 unplaced scaffolds. These toplevel sequences are assembled from 20,423 contigs with a N50 value of 191kb. The N50 size is the length such that 50% of the assembled genome lies in blocks of the N50 size or longer. Click here to go to the mouse Pre! site, where you can view mouse protein, cDNA and EST alignments, as well as alignments of the Ensembl release 66 mouse translations. This assembly will undergo full automatic gene annotation in due course.