I have the genomic coordinates of mouse mm10 from ensembl biomart (Ensembl genes 80). I was using IGV mouse mm10 for visualising some of the mouse genomic coordinates. Why there are differences in the position of genes when comparing the results, even though they are from the same mm10 build. For eg. Mycl postion in IGV is chr4:122,994,099-123,004,480 and from ensembl its showing chr:4-122,995,652 -123,002,485.