[ensembl-dev] mus_musculus chromosome 22?

[Ido M. Tamir]

Hi,
why does the ensembl mouse have 22 autosomes?
ftp://ftp.ensembl.org/pub/current_mysql/mus_musculus_core_60_37m/karyotype.txt.gz

O.k. 20-22 consist only of tip+cen, but still...

thanks,
ido