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important feature of the sunflower genome, the extensive duplication, since
most of the isozymes, such as ACP, ADH, EST, IDH, MDH, ME, PGI, PGM
and SDH, had two or more loci. These observations support the hypothesis
of the allopolyploid origin of the sunflower genome (Heiser and Smith 1955;
Jackson 1983).
3.2.2.2 Storage Protein Markers
Sunflower seeds contain two major protein classes, albumins and globulins.
Several seed storage protein markers were also reported in sunflower. Kortt
and Caldwell (1990) resolved eight distinct components of the low molecular
weight 2S albumins. The complete amino acid sequence of sunflower
albumin 8 (SFA8), the major methionine-rich 2S protein of sunflower seed,
was determined alone with a cDNA clone which codes for this protein
(Kortt et al. 1991). Anisimova et al. (1995) demonstrated that SFA8 is
polymorphic among sunflower breeding lines. Serre et al. (2001) used SDS-
PAGE to separate the albumins into eight to ten bands in the molecular
weight range of 10 to 18 kDa. Two of these bands, 14.5 or 15.5 kDa segregated
in a co-dominant fashion in the 150 F
2:3
families derived from ZENB8 × HA
89. This 2S albumin locus was mapped in the interval between the markers
ZVG0051 and ZVG0052 of linkage group 11 of a public sunflower RFLP
map. Polymorphisms of the high molecular weight 11S globulins have been
detected in both molecular weight and charge among sunflower breeding
lines (Anisimova et al. 1996) and between species (Anisimova et al. 1993).
The genes coding for this protein family were isolated and characterized
(Vonder Haas et al. 1988). Unfortunately, no genetic mapping was conducted
for these genes.
Konarev et al. (2000) characterized six groups of trypsin inhibitors in
sunflower seeds. These included three groups of trypsin/subtilisin
inhibitors, one major and two minor groups of trypsin inhibitors. Each group
showed polymorphism among breeding lines and trypsin/subtilisin
inhibitors also varied among wild species. Genetic analysis showed that
the major trypsin inhibitor and three groups of trypsin/subtilisin inhibitors
are each controlled by a single locus, and three loci coding for trypsin/
subtilisin inhibitors (groups C, D
a
and D
b
) were loosely linked with
recombination values ranging from 0.23 to 0.40.
3.3 DNA-based Marker Techniques
Numerous techniques have been developed to detect polymorphism at the
DNA level in animals, plants and microbes. A DNA marker visualized with
a special technique reveals the DNA variation among the samples and is
analogous to a traditional heterozygous allelic pair. This section briefly
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