We made a mistake! ms35 is allelic to ms23, but what is the correct map location? --Trimnell, MR, Fox, TW, Albertsen, MC During conducting some cytology work in our lab, Shannon Stenejhem found a reference in a 1985 MNL article written by DP West and MC Albertsen (MNL 59:87) that ms23 was allelic to a male-sterile mutant designated ms*-Bear7 by the late Earl Patterson and who later designated it as ms*-6011 (MNL 69:126-128). In 1999, we identified ms*-6011 as being a new male-sterile mutant, and we designated it as ms35 (MNL 73:49-50). For whatever reason, we did not consider all the available information when we gave it the ms35 designation. One of the reasons this may have occurred is that ms23 had been reported to be located on chromosome 3L (MNL 62:71); whereas ms35 had been reported to be located on chromosome 9L (MNL 69:126-128).

We decided that we should first find out if the 1985 allele test data was correct. We made test-crosses between ms23 and ms35 in the summer of 1999 and grew the progeny in the 1999 Hawaii winter nursery. The two male-sterile mutants were found to be allelic (data shown below):
 
Female
Male
Progeny
X2(1:1, P>0.050=3.84)
ms23 Hom
ms35 Het
19 Fertiles
20 Steriles
0.03
ms35 Hom
ms23 Het
18 Fertiles
16 Steriles
0.12

We then planted the original ms35 seed that Earl gave us and test-crossed it to both ms23 and the later developed ms35 material, to make sure seed stocks had not been "mixed up". These were grown in our 2001 Johnston, IA, nursery and also were found to be allelic (data shown below):
 
Female
Male
Progeny
X2(1:1, P>0.050=3.84)
ms35-Bear7 Hom
ms23 Het
13 Fertiles
25 Steriles
3.79
ms23 Hom
ms35-Bear7 Het
23 Fertiles
15 Steriles
1.68
ms35 Hom
ms35-Bear7 Het
21 Fertiles
23 Steriles
0.09

In the 1999 Hawaii winter nursery, we grew an F2 that had been constructed to chromosome arm map ms35 by using SSR markers. We wanted to compare the SSR-derived map location with the B-A translocation-derived map locations previously assigned to ms23 and ms35. Leaf punches were taken from 24 male-sterile plants and from 24 male-fertile plants for DNA isolation. 96 SSR markers, dispersed throughout the genome, were used to genotype this family. No linkage was found with any markers on chromosome 3 or on chromosome 9. Because of this conflicting data, we are now preparing to re-map ms23 with other SSR markers in the hopes of determining the correct map location.
 
 


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