Maize Genetics Cooperation Newsletter vol 81 2007
BROOKINGS, SOUTH DAKOTA
South Dakota State
University
Mapping
of ragged (rg*) mutation using classical and molecular markers
--Whalen, RH; Brozik, M; Auger, D
A recessive mutation resulting
in abnormal leaves and shorter plants was found in the inbred W22. This apparently spontaneous mutation
was informally designated �ragged� (rg*) in reference to its cut or torn
leaves (Fig. 1). It was found to
be due to a single
Figure
1. Leaf of rg*/rg* plant. (For color see
online.)
recessive gene, and using
B-A translocations, was found to be on the long arm of chromosome 5. We mapped it more precisely in a
three-point linkage test with red aleurone (pr) and the SSR molecular
marker umc1221. The reference allele for umc1221 has seven tandem copies of
CT. Determination of polymorphisms
was accomplished through electrophoretic separation in a 3.5 % agarose TAE gel
of polymerase chain reaction (PCR) products that included the SSR. The mapping sample was produced by crossing
an F1 heterozygous for all three loci by a homozygous testcross parent (Fig.
2). The data from the mapping
sample are presented in Table 1.
Figure
2. Mapping scheme. 1221s refers to the slower band of umc1221; 1221f refers to the faster band
of umc1221. Pr refers to the wild-type allele of pr1; pr refers to the red allele. Rg refers to the wild-type
allele of the rg* locus; rg refers to the mutant allele.
Table
1. Recombination data.
|
|
Family
1 |
Family
2 |
Total |
|
|
|
Parentals |
umc1221-f Pr Rg umc1221-s pr rg |
70 77 |
80 88 |
157 158 |
315 |
|
SCOs Region
1 |
umc1221-f pr rg umc1221-s Pr Rg |
7 3 |
7 8 |
14 11 |
25 |
|
SCOs Region
2 |
umc1221-f Pr rg umc1221-s pr Rg |
5 8 |
2 6 |
7 14 |
21 |
|
DCOs |
umc1221-f pr Rg umc1221-s Pr rg |
3 0 |
0 1 |
3 1 |
4 |
|
Totals |
173 |
192 |
365 |
|
|
The rg* locus is located on the long arm of chromosome 5, 6.8 � 1.4 cM from pr1, which is 7.9 � 1.4 cM from umc1221. The map is shown in Fig. 3. This places the new locus distal to pr1.
Figure
3. Map of new locus relative to pr1 and umc1221.
Please Note: Notes submitted to the Maize Genetics Cooperation
Newsletter may be cited only with consent of authors.
