Chromosome aberrations in 'Chinese Spring' genetic stocks
Introduction
An important tool for mapping genes and markers in wheat is the set of
genetic stocks derived from 'Chinese Spring' which lack a chromosome
(nullisomic-tetrasomic) or a chromosome arm (ditelosomic). See here
for a complete list of available NT and
Dt stocks. See Raupp
et al. for description and nomenclature of these and other
wheat genetic stocks.
A recent collaborative study has shown that some of these stocks carry
additional chromosomal alterations besides their nominal one. These
details must be taken into account in interpreting experimental
results based on the stocks. The aberrations are of several types:
- Additional terminal deletions. See below for details.
- Impure backgrounds. Some stocks were originally derived from lines
other than Chinese Spring, and contain residual markers from those
sources: N6D-T6B, N7D-T7B; Dt2AS, Dt2DL, Dt4AL, Dt6AL, Dt7BL.
- Homoeologous recombinations. The Ph1 gene which suppresses pairing and
recombination between homoeologous chromosomes within a group is on 5BL.
Thus nulli-5B lines are liable to homoeologous recombination, and several
examples have been found in different stocks of N5B-T5D.
- Asynapsis. Dt3BS stocks may contain various deletions due to asynapsis.
- Misidentifications. The stock called "N6B-T6A" is actually N6B-T6D.
"Dt7DL" is actually Dt7DS.
Please consult the reference for additional details and suspicions about
other stocks, and for possible sources of corrected stocks.
Reference
KM Devos, ME Sorrells, JA Anderson, TE Miller, SM Reader, AJ
Lukaszewski, J Dubcovsky, PJ Sharp, J Faris, MD Gale. 1999. Chromosome
aberrations in wheat nullisomic-tetrasomic and ditelosomic lines.
Cereal Research Communications 27:231-239.
Gratuitous additional partial terminal deletions
Summary
|
Stock |
Deletion in |
Remark |
|
Nullisomic-tetrasomic |
|
|
|
N1A-T1D |
7DL |
|
|
N5A-T5B |
2DS |
Only CSIRO, not JIC or CU stocks |
|
N7D-T7B |
2BS |
Only CSIRO, not JIC or CU stocks |
|
Ditelosomic |
|
|
|
Dt1BS |
7AL |
|
|
Dt2AS |
3BS |
|
|
Dt2BL |
4AL |
|
|
Dt5BL |
2DS |
Possibly only in JIC stock |
|
Dt6BS |
2BS |
|
Deletion maps
Legend. Open bars represent deletions, and the stocks containing
them are named at the top of the chromosomes. Markers in the hatched
regions have not been tested against the N-T lines. Additional unmapped
markers within the deletions are shown in boxes above the chromosomes.
from Katrien Devos, 23mar00
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