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of six isozyme marker loci in the selfed progenies of cultivated annual
sunflower lines collected by the United States Department of Agriculture-
Agricultural Research Service (USDA-ARS). They found that Chi-
square goodness-of-fit
tests verified the genetic segregation for the six enzyme
marker loci
including a peroxidase (PRX) locus,
Prx3
, a malate
dehydrogenase (MDH) locus,
Mdh1
, a
6-phosphogluconate dehydrogenase
(PGD) locus,
Pgd1
, a glucose-phosphate
isomerase (PGI) locus,
Gpi2
, a
phosphoglucomutase (PGM) locus,
Pgm4
and an isocitrate
dehydrogenase
(IDH) locus,
idh2
. They also determined that
Prx3
is linked
to
Pgm4
with a
recombination value of 0.14 ± 0.02. Therefore,
their results suggested that
the six enzyme loci could be mapped to five different
linkage groups. Lay et
al. (1988) reported the investigation of nine isozyme loci in six F
2
populations.
They found: 1) a distorted segregation for two loci,
Mdh1
and an acid
phosphatase (ACP)
locus
, Acp2
, 2) a confirmation of the linkage relationship
between
Pgm4
and
Prx3
reported by Kahler and Lay (1985), but the
recombination value dropped to 0.055± 0.01, and 3) a newly identified
linkage relationship between
Acp1
and
Pgd1
with a recombination value of
0.05± 0.01. Quillet et al. (1995) followed six isozyme loci in the BC
1
population
derived from an interspecific cross (
H. argophyllus
x
H. annuus
cv. RHA 274).
Two loci,
Mdh2
and
Acp1
were unlinked to other markers; another two,
Pgm1
and a malic enzyme (ME) locus,
Me1
,
were mapped to two separate
linkage groups; and the remaining two,
Mdh1
and a shikimate
dehydrogenase (SDH) locus,
Sdh1
,
were linked at a map distance of 47.2
cM. Fambrini et al. (1997) reported a co-dominant locus controlling the two
distinct achromatic
bands for Cu/Zn superoxide dismutase (Cu/ZnSOD
Chl
).
The variant was identified in an ABA-deficient mutant,
w
-
1
, on which the
linkage study was conducted. Mestries et al. (1998) reported the mapping of
six isozyme loci onto five linkage groups of a restriction fragment length
polymorphism (RFLP) linkage map constructed from a single F
2
population
generated by crossing two inbred lines GH and PAC2. The six mapped loci
included a glutamate-oxaloacetate transaminase
(GOT) locus,
Got1
, on
linkage group (LG) D,
idh1
and
pgi3
on LG H,
Me
on LG H,
Pgd2
on LG J and
Sdh
on LG N. The mapping distance between
idh1
and
pgi3
was 45
centiMorgans (cM). Carrera
et al. (2002) mapped five isozyme loci in an F
2:3
population from which a linkage map of restriction fragment length
polymorphism (RFLP) markers had been constructed and released to the
public (Barry et al. 1997). Three of the loci,
Est1
,
Gdh2
, and
Pgi2
were mapped
to linkage groups 3, 14 and 9, respectively. The other two,
acp1
and
pgd3
,
were linked in LG 2 of the map with a mapping distance of 11.3 cM.
Since there is no classical linkage map for sunflower, the linkage group
numbers were independently assigned in different laboratories. The
relatively small number of mapped isozyme loci limits these loci in genome
mapping of the sunflower crop. However, these studies did reveal an
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