Tpi-1 and Gapd are linked very closely on mouse chromosome 6.

Mutations in the structural genes for triosephosphate isomerase and glyceraldehyde-3-phosphate dehydrogenase activity in the mouse, selected after mutagen treatment, were used to estimate the map distance between the two loci. It is shown that Tpi-1 and Gapd are closely linked on chromosome 6, with a recombination frequency of 0.1 +/- 0.1%.