ABSTRACT & LINKS
Koumbaris GL and Bass HW (2003)
A new single-locus cytogenetic mapping system for maize (Zea mays
L.): overcoming FISH detection limits with marker-selected sorghum
(S. propinquum L.) BAC clones.
The Plant Journal 35(5):647-659.
[
Abstract-Links
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PubMed 12940957
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Plant J-online
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ABSTRACT:
The development of a cytogenetic map for maize (Zea mays L.) is shown to be
feasible by means of a combination of resources from sorghum and oat that
overcome limitations of single-copy gene detection. A maize chromosome-addition
line of oat, OMAd9.2, provided clear images of optically isolated pachytene chromosomes
through a chromosome spread and painting technique. A direct-labeled oligonucleotide
FISH probe MCCY specifically stained the centromere. The arm ratio (long/short) for
maize chromosome 9 in the addition line was 1.7, comparable to the range of 1.6 to 2.1
previously reported for maize chromosome 9. A sorghum (Sorghum propinquum L.) BAC library
was screened by hybridization with each of three maize core bin marker (CBM) probes:
umc109 (CMB9.01), umc192/bz1 (CMB9.02), and csu54b (CMB9.08). A single BAC clone for each
marker was chosen; designated sCMB9.1, sCBM9.2, or sCBM9.8; and used as a FISH probe on
pachytene spreads from OMAd9.2. In each case, discrete FISH signals were observed, and
their cytogenetic positions were determined to be 9S.79 (at position 79% of the length of
9 short arm) for sCBM9.1, 9S.65 for sCBM9.2, and ~9L.95 for sCBM9.8. These map positions
were colinear with linkage-map positions for these and other loci common to the linkage and
cytogenetic maps. This work represents a major breakthrough for cytogenetic mapping of the
maize genome and also provides a general strategy that can be applied to cytogenetic mapping
of other plant species with relatively large and complex genomes.
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