Structure of the human MTHFR gene as determined by Goyette et al, 1998.  Homberger et al (2000) later identified two additional exon sites. Numbers in the above figure indicate the locations of the introns.  E=EcoRI site, X=XbaI site, A=polyadenylation site.  Information on the introns is given below: 

Intron Approximate size (kb)
1 1.5
2 0.8
3 4.2
4 0.8
5 0.35
6 0.25
7 0.3
8 1.5
9

1.3
10 0.3

 

Up