Maize
Genetics Cooperation Newsletter 80. 2006.
The following notes present follow-up tests on mutants that were earlier located to chromosome arms and were subsequently tested with SSRs by Chris Carson. A few were unplaced previously. I appreciate advice from Phil Stinard, Janet Day Jackson, and Marty Sachs in pointing out potential allelisms that I might overlook, and in cross-checking against their records.
Tests of blh*-N495B on 1S: this mutant is allelic to pg15. Both show pale green leaves that develop bleached necrotic cross-bands. The new allele is weak but viable; the other is lethal. With the suggestion of Phil Stinard, allelism tests were conducted after map locations with SSRs suggested potentially related phenotypes, including pg15. The common phenotype suggests diurnal induction of necrosis. This allele is designated pg15-N495B. It complements nec2 and zb4, and its phenotype is distinct from zb3, which was located near tub1 (at 2.5 on IBM2, 0.61 conventional cM) by Rugen et al. (MNL 75:17-18, 2001). Tests with zb3 and zn2 (unplaced) were attempted, but failed because the mutants were unseen in tester families.
Because both have been mapped in independent experiments, map data can be merged as follows:
(blh*-N495B -0- sr1) in 61 testcross individuals. Had 1 recombinant occurred, the distance would be 1.6�1.6
cM. -- Hoisington, DA. 1984. MNL 58:82-84.
(blh*-N495B - 14�5
- umc1568) in 21 F2 recessive individuals
(42 strands). --Carson, C. 2001, MMP.
(pg15 -11�5- umc1160) -- Carson, C. 2001, MMP.
Mapping of sr1 has been reported with SSR markers:
umc1177 –
24�7 - sr1 - 14�5 - umc1166 in 42 strands
-- Carson, C. 2001, MMP.
The SSRs are on IBM2 chromosome 1 in this order at these coordinates (to aid in estimating intervals, division by 4 is applied as an approximation to conventional cM):
umc1177 10.50 (~2.6) (~12 on the Genetic 2005 map)
umc1160 108.30 (~27.1) (~29 on the Genetic 2005 map)
umc1166 133.60 (~33.4) (~34 on the Genetic 2005 map)
umc1568 141.80 (~35.5) (~39 on the Genetic 2005 map)
The
indicated order and estimated distances are umc1177 -17- (umc1160, sr1, pg15) -5- umc1166 -5- umc1568. If the
position of pg15 is as much as 11 units
to the left of umc1160, it may be to
the left of sr1, which is roughly 14
units to the left of umc1166. In any event, pg15 is placed near 29, the location assigned to sr1 on the Genetic 2005 map.
Tests of w18 in bins 1.09-1.11: this mutant complements l17, which maps in bins 1.09-1.11. The phenotype of w18 seedlings is pale yellow (aka white-luteus) with pale green streaks at the leaf base. In selfs from crosses of w18-N495A (Stock 128A) onto both A619 and B73, seedlings are also faintly green. Complementation also has been found between w18 (which is within 4 cM of umc1306 at 880.84 on IBM2 neighbors, i.e., between ~195 and 205 on the Genetic 2005 map) and w24 (which is about 3 cM to the left of umc1446 at 781.60 on IBM2, i.e., near 175 on the Genetic 2005 map). Data place l17 within 17 cM of bnlg1347 at 933.09 in IBM2 neighbors, i.e., between ~192 and 226 on the Genetic 2005 map.
The
phenotype of seedlings of l17 is
described as luteus yellow and crossbanded. In selfs from crosses onto both
A619 and A632, the luteus seedlings are faintly green. The luteus trait is
associated with pale yellow (lemon) endosperm, an association that has not been
recorded previously.
Tests of bl*-N43 (blotchedN43) in 1L: this mutant is allelic to zb7 and can be designated zb7-N43. Complementation is found with v22, and complementation has previously been found with pg16. The phenotype of zb7-N43 is pale green in seedlings, sometimes cross-banded; irregular, pale green, bleached areas occur in mature plants. The phenotype of zb7 (zebra7, zb*-N101) seedlings is strongly cross-banded on green, with bleached cross-bands in mature plants.
Because
both have been mapped in independent experiments, map data can be evaluated
together:
umc1335 umc1446
-15- bl*-N43 -20- fdx3-- Carson, C. 2002, MMP.
bz2 -23- zb7 -9- gs1 -26- bm2 1988 --
Sisco, PH. 1988. MNL 62:124.
Mapping of gs1 with
RFLP markers has been reported as follows:
gs1 -2- umc72b - phi1 -7- bnl8.29a - bm2 - acp4 -- Sisco, PH. 1989. MNL 63:140.
The markers on IBM2 neighbors chromosome 1 are at these coordinates:
umc1446 781.60 (~195.4) (~177 on the Genetic 2005 map)
bz2 787.20 (~196.8) (~178 on the Genetic 2005 map)
umc72b 920.88 (~230.2) (~205 on the Genetic 2005 map)
fdx3 1098.40 (~274.6) (~244 on the Genetic 2005 map)
The MMP data are compatible with the Sisco data, which contributed placement of zb7 between about 197 and 201 on the Genetic 2005 map. The indicated order and estimated distances are umc1446 – bz2 -23- zb7 -9- gs1 -2- umc72b.
Tests of l*-85-3457-40: this �Phenotype Only� luteus seedling mutant has been placed with the following SSRs by association in recessive bulks in F2:
umc1396 548.40 (~137.1) bin 1.06
umc1446 781.60 (~195.4) bin 1.08
umc1306 880.84 (~220.2) bin 1.09
Estimated
location for the gene is between ~145 and 185 cM on the Genetic 2005 map. A prospect for test is l17, in bin 1.09-1.10 at approximately 209 +/- 17 on the
Genetic 2005 map.
Tests of et*-N868A in bin 2.00-2.02: this mutant complements rgh2 in bin 2.00-2.02. It also complements et2 in bin 2.02-2.04. Previous tests have found et*-N868A and stf*-N868B to be allelic. The gene is assigned the symbol et3, alleles et3-N868A and et3-N868B. It is located within about 10 cM from umc1265 at 77.70 on IBM2 (i.e., between ~10 and 30 on the Genetic 2005 map).
Tests of cb2 (was cb*-N652B) in bin 2.02-2.03: this mutant complements al1 in bin 2.01. The location of cb2 is within about 15 cM from ole1 at 216.50 on IBM2 (i.e., between ~40 and 70 on the Genetic 2005 map).
Tests of of v*-5537 on 2L: new tests show that v*-5537 and v4 are allelic, a correction to prior information in 1972 Cooperators� notes in MNL. Their phenotypes are very similar. The mutant complements v24 and wlv1. This allele can be designated v4-5537.
Because
both have been mapped in independent experiments, map data can be evaluated
together:
(umc1635 bnlg1887 -7-
v*-5537) -17- umc1042 – Carson, C. 2002, MMP.
gl2 -38- mn1 -16- v4 -- Van Horn, J. 1968. MNL 42:156-157.
The markers are on IBM2 chromosome 2 in this order at these coordinates:
mn1 328.79 (~82.2)
umc1635 344.80 (~86.2)
bnlg1887 346.50 (~86.6)
umc1042 466.65 (~116.7)
The
indicated order and estimated distances are mn1 - umc1635 - bnlg1887 -7- v4 -17- umc1042, compatible with the location of v4 between 100 and 104 on the Genetic 2005 map.
Tests
of w*-N77, w*-N332, and w*-N1907 on
2L: these three mutants are allelic to w3 and can be designated accordingly. Mapping data include:
w*-N1907 -0- bnlg1045 and bnlg2077
bnlg1887 -13-
w*-N77 -24- umc1042
umc1004 bnlg2077 -11- w*-N332 -18- bnlg1520
The markers are on IBM2 neighbors chromosome 2 in this order at these coordinates:
bnlg1887 346.5 (~86.6)
umc1004 381.8 (~95.5)
umc1042 466.65 (~116.7)
bnlg1045 471.21 (~117.8)
bnlg2077 474.8 (~118.7)
bnlg1520 596.55 (~149.1)
These
data are inconsistent for order, most probably because of the high potential
for errors due to chance in small samples. The data applied to obtain w3 placement for the Genetic 2005 map at 135 +/- 5 have
contradictory distance estimates and are no more clear with the above data.
Tests
of o*-N999A in bin 2.07-2.09: this
mutant complements dek4, dek23, and dek16 on 2L. Seeds have an
opaque phenotype and tend to be reduced in size. The gene was previously given the symbol o16 but this was held pending these tests. The symbol o16 can be assigned. It is located within 20 cM of umc1604, which is at 523.50 on
IBM2 (i.e., between ~137 and 177 on the Genetic 2005 map). Tests with o*-N1242A and ptd*-N901A in the 2005 season were unsuccessful.
Tests of o*-N1195A in bin 2.08-2.09: this mutant complements dek23 in 2L. Prior tests have shown complementation with o16. Tests with dek4, dek16, and o*-N1242A in 2005 were unsuccessful.
Tests of d*-N282 in 3.06-3.07: this mutant is allelic to na1 and can be designated na1-N282. Linkage data have been obtained as follows:
umc1266 -17- d*-N282 -27- bnlg197
Marker
locations are as follows:
umc1266 411.60 (~102.9)
bnlg197 511.50 (~127.9)
By
apportioning the interval, na1 can be
estimated to be at about 101 +/- 3 cM on Genetic 2005, compared to its current
placement at 108 +/- 3.
Tests of wl*-N1906 in bin 3.08-3.09: this mutant complements wlu1, y10, et1, v33, and w19 in this region (w19 is the designation given to the albinism expressed in sectors when the a-x1 deficiency is uncovered). The symbol wlu8 is assigned. Linkage data have been obtained as follows:
(wl*-N1906
-19- bnlg1182) 2001
umc1102 -26- wl*-N1906
2002
umc1140 -12- wl*-N1906 -12- (umc1594, umc1136)
Marker
locations are as follows:
umc1102 312.80 (~78.2)
umc1140 609.20 (~152.3)
bnlg1182 738.68 (~184.7)
umc1594 828.90 (~207.2)
umc1136 835.91 (~209.0)
The
indicated order and estimated distances are umc1140 -12- wlu8 -12- umc1594, and wlu8 at about
720 on IBM2, i.e., between ~140 and 150 cM on the Genetic 2005 map. This places the gene near but not
within the a-x1 deficiency, which
encompasses a1 at 139.9 and sh2 at 141.9.
Tests of spt*-N1620B in bins 4.03-4.05: this mutant complements spt2. The two phenotypes are distinct, spt2 showing rounded green spots on a pale field or rounded pale spots on a green field, while spt*-N1620B shows irregular or rectangular yellow spots on a green field. The symbol spt3 is potentially applicable, but deferred pending additional tests. Linkage data have been obtained as follows:
(spt*-N1620 -17- umc1117)
Marker umc1117 is at 218.50 on IBM2, placing spt3 between ~33 and 67 on the Genetic 2005 map.
Tests of v*-N1835 in bin 5.05-5.07: this mutant complements vp2 and v12. The symbol v36 is assigned. This mutant has a briefly expressed, white-luteus virescent phenotype. Linkage data have been obtained as follows:
(v*-N1835 umc1019) association in recessive bulks in F2, where the estimated range is 15 units around the marker. Marker umc1019, aka umc126a, is at 469.60 on IBM2 and at 121.00 on the Genetic 2005 map, placing v36 between ~105 and 135 on the Genetic 2005 map.
Tests of wl*-N1393B in bin 5.05-5.07: this mutant complements v36, vp2, and v12. It has a white-lutescent phenotype. The symbol wlu9 is assigned. Linkage data have been obtained as follows:
(wl*-N1393B umc1591)
association in recessive bulks in F2.
Marker umc1591 is at 314.10 on
IBM2, placing wlu9 between ~75 and 105
on the Genetic 2005 map.
Tests of mn*-N1536 in bin 5.04-5.05: this mutant complements dek9, dek26, dek27, dek29 dek33, prg1, and ren1. It has miniature kernels with loose pericarp. The symbol mn5 is assigned. Linkage data are as follows:
(mn*-N1536
umc1224) association in recessive bulks in
F2, linkage within 15 cM. Marker umc1224 is at 315.22 on IBM2 neighbors, and mn5 is uncovered by TB-5La at ~97, placing mn5 between ~96 and 106 on the Genetic 2005 map.
Tests
of al*-84-5020-32 on 5: this �Phenotype
Only� mutant complements pb4 and
ppg1.
It was unplaced prior to tests showing association with umc1591 in F2 recessive bulks, placing it in bin 5.03-5.04
between ~75 and 105 on the Genetic 2005 map. Mutant seedlings are pale green,
grainy-streaked, and sometimes cross-banded; plants are variably unthrifty,
with albescent-grainy leaves.
Tests were unsuccessful in the 2005 season with crp2 (aka hcf143), which is uncovered by TB-5Sc (i.e., is between ~0 and 82
on the Genetic 2005 map) and has a pale green seedling phenotype. Tests were also unsuccessful with csy1, which is at 210.19 on IBM2 neighbors, i.e., at ~57 cM on
the Genetic 2005 map, and has a luteus yellow seedling phenotype. The phenotypes and/or locations of crp2 and csy1 are
distinct from those of this albescent mutant. The symbol al2 is
potentially applicable, but is deferred pending additional tests.
Tests
of fl*-N1145A on 5L: this floury is
allelic to dek33 and can be
designated dek33-N1145A. Both display floury, wrinkled or
shrunken kernels. Linkage data for
both mutations are as follows:
(fl*-N1145A bnlg609)
association in recessive bulks in F2.
a2 -7- bm1 -13- dek33 -21- pr1 – Neuffer, 1992. MNL 66:39
Markers are placed as follows:
bnlg609 500.70 on IBM2 (~126
on the Genetic 2005 map)
a2 295.04 on IBM2 neighbors 82
+/- 1 on the Genetic 2005 map
bm1 92
on the Genetic 2005 map
dek33 98
+/- 3 on the Genetic 2005 map
pr1 109 on the Genetic 2005 map
Based
on linkage with bnlg609, dek33 should fall between ~110 and 140 on the Genetic 2005
map. The order and distance data
are inconsistent -- indeed, several other sources of data for the placement of pr1 show conflicts inter se, so a definitive map involving pr1 and dek33 awaits
future resolution. Incomplete
complementation tests of dek33-N1145A
with dek9, dek26, dek27, prg1, and ren1 did not reveal
allelism but did not exclude it in any instance.
Placement of vp*-86-1407-15 on 7S and test with vp9: this �Phenotype Only� mutant has been placed with the following SSRs by association in recessive bulks in F2:
bnlg2132 53.30 (~13.3)
umc1015 (php20569a) 300.00 (~75.0)
umc1426 47.8 (~11.9)
Estimated location for the gene is between ~25 and 30 cM on the Genetic 2005 map. This is a pale endosperm, viviparous-embryo mutant. Two tests have shown complementation with vp9, which is at ~48 on the Genetic 2005 map, but additional evidence should be obtained before designating a new viviparous in such close proximity.
Tests of vp*-8113 on 7S: this mutant gave positive allelism tests with vp9 and could be designated vp9-8113 if further tests confirm it. Map data that can be merged are as follows:
(vp*-8113 o2 bnlg1247)
associated in recessive F2 bulks, the mutant being within 15 cM of each marker.
o2 -7- vp9
vp9 -11- gl1
Markers are placed on IBM2 neighbors as follows
o2 122.40 (~30.6)
bnlg1247 186.3 (~46.6)
gl1 191.31 (~47.8)
On
the recent Genetic 2005 map o2 is
placed at 41.0, vp9 is estimated to be
at ~48 +/- 2, and gl1 at ~60 +/- 4
cM. The new data do not improve on
the estimated location for vp9.
Tests of v*-N829A on 9S: this mutant complements v31 and w*-9000. Tests with yg2 were ambiguous, with clear complementation in two direct tests but possible allelism in a third. The phenotype of v*-N829A is very similar to that of yg2, and mutant pools show linkage within 15% of bnlg1724. Additional tests vs. yg2 are needed.
Tests of w*-9000 on 9S: this mutant complements the wd1 and pyd1 deficiencies, w11, l7, ar1, pg12, w2, and yg2. Mutant pools show linkage within 15 cM of bnlg1810, which is very near c1. A remaining prospect for allelism is l6.
The phenotype of seedlings of l7 is described as luteus yellow. In selfs from crosses onto both A632 and B73, mutant seedlings are faintly green.
Tests of yg*-N2021 on 9S: this mutant complements pg12, ar1, v1, and v31. Mutant pools show linkage within 15 cM of umc1417, which is near gl15. Remaining prospects for allelism are w11 and v30.
Tests of ij*-N504A on 10S: this mutant is allelic to sr3 and can be designated sr3-N504A. Its recombination has been reported to be 2% with umc1336, which is on the long arm of 10. Both ij*-N504A and sr3 are uncovered by TB-10Sc, and sr3 is 3 cM from T9-10b, which is at 10S.40. The reported low recombination of ij*-N504A with umc1336 contradicts its TB placement data and placement of its allele, sr3.
Tests
of pg*-N1224C on 10L: this mutant is
allelic to v29 and can be
designated v29-N1224C. TB-10L20
uncovers v29. Mutant pools show linkage within 15 cM
of umc1640, and pools for v29 show linkage within 15 cM of bnlg1360. Both
SSRs are in bin 10.07, 14 cM apart on the IBM2 2004 neighbors map, or near 3.5
cM apart on the Genetic map. The
combined data suggest a change in placement of v29 to 123 +/- 10 on the Genetic 2005 map.
_________________________________________________
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