Plant Genome II Conference
Town & Country Conference Center, San Diego, CA, January, 1994.
PG-II: CONSTRUCTION OF A COMPOSITE MAIZE MAP OF EXPRESSED SEQUENCES,
BASED ON 4 INDIVIDUAL MAPS
CONSTRUCTION OF A COMPOSITE MAIZE MAP OF EXPRESSED SEQUENCES,
BASED ON 4 INDIVIDUAL MAPS.
M. Causse, A. Maurice, C. Damerval, S. Santoni, D. de Vienne,
Station de Genetique Vegetale, INRA, CNRS-URA 1492, UPS, Ferme du
Moulon, 91190 Gif s/Yvette, France.
Candidate gene approach is a straightforward way to identify
QTLs and study their function. In plant breeding, if one had the
QTL itself instead of a linked marker, the efficiency of market-
assisted selection would increase considerably. For this
purpose, we are constructing a maize genetic map based on
expressed sequences. Our map is based on the data from 4
segregating populations, one F2 And 3 recombinant inbred lines
populations. In all, more than 500 individuals were genotyped.
Four sources of markers were used: (i) known function genes
obtained from laboratories which cloned them; (ii) polypeptides
revealed by two-dimensional electrophoresis in our laboratory;
(iii) sequenced cDNA for which no homology was found in gene
banks, kindly provided by C. Baysdorfer (California State Univ.);
(iv) anonymous probes of the maize core map (Gardiner et al,
1993, Genetics 134: 917-930). These markers were useful to
integrate our map with the other maize maps. Mapping cDNA
revealed some unexpected problems, among which the high rate of
multicopy probes. No specific organization is deduced, excepted
the duplications already mentioned. As 4 populations were used,
we compared the recombination fractions among the populations.
Heterogeneity was frequently observed.
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