4. The locus of vestigial - A 5-point test of Vg with br f an bm2 has given the following results from the F₁ genotype

Per cents of recombination are as follows:

br-Vg 3.3, br-f 3.9, br-an 19.6, br-bm2 44.8, Vg-f 0.6, Vg-an 18.4, Vg-bm2 44.8, f-an 18.1, f-bm2 45.1, an-bm2 35.9.

Sprague (Jour. Heredity 30: 143-145, 1939) has shown that Vg is between br and f, a locus supported by the data presented here. I cannot, however, agree with his suggested order of f Vg br bm2. His three-point test involving a very short region with a very long one is unsatisfactory as pointed out by him, but the data as reported suggest the order br Vg bm2. His four-point test, again involving a very long region with very short ones, as a whole indicates the order suggested by him, but, when bm2 is disregarded, the resulting three-point data are:

These data, obviously, afford no evidence of the order of the genes except that Vg is between br and f.