Molecular Plant Breeding 2016, Vol.7, No.14, 1
-
10
2
FISH technology have developed suceessfully on other crops (Mukai et al.,1993; Cheng et al., 2002 ; Xiong et al.,
2004). But research on cotton far lags behind those, main because cotton cell has more density cytoplasm, more
hard cell wall, more number of chromoses and smaller size compare with other crops, which lead to cotton cell
processing more difficult in prepare of high quality chromosome slides. In recent years, with the breakthrough of
the bottleneck technology, cotton FISH research is developing rapidly(Liu et al., 2005 ; Wang et al., 2009; Wu et
al., 2008 ; Gan et al., 2013 ; Zhang et al., 2014; Cui et al., 2015).
At present, about the great theories on
Gossypium
such as origin of species, evolution and classification had
already formed the basic agreement. However, there still exist dissensions on the specific donors of the 5
tetraploid cotton species, and the germplasm disproportionation in the process of origin, and the homologous
degree between different genome species of
Gossypium
or within one genome species(Liu et al., 2003 ;Wang KB
et al., 2008)
.
Our laboratory has made a great progress on using FISH technology to research the origin and
evolution of cotton genomes and the interspecific genetic relationship or the genonomy of
Gossypium
(Wang et al.,
1999; Wang et al., 2001; Liu et al., 2005; Wu et al., 2008; Gan et al., 2013).
In this study, GISH(Genomic
in situ
hybridization, one of the FISH technology) was used to the two cultivated
alltetraploid cottons somatic metaphase chromosomes of (AD)
1
and (AD)
2
，
and used All 3 diploid A and 13
diploid D cotton gDNA (genomic DNA) as probe blocking with ssDNA, in order to further explore the specific A
and D sub-genome progenitor donors of (AD)
1
and (AD)
2
, and their genetic relationships; homologous degree
between each tested cotton genome species. Wished to provide a beneficial enlightenment and help for the genetic
improvement and suggest the preferred
Gossypium
species for genome sequencing.
1 Results and Analysis
1.1 GISH of (AD)
1
and (AD)
2
with all 3 diploid A cotton gDNA as probes respctively
GISH of the somatic metaphase chromosomes of (AD)
1
and
(AD)
2
both with all 3 diploid A (A
1
, A
2
and
A
1-a
)
gDNA as probes respectively, blocking with ssDNA(salmon sperm DNA).The results showed that the red
hybridization signals were mainly distributed on the longer 13 pairs of A sub-genome chromosomes of (AD)
1
and
(AD)
2
(As shown in Figure 1), and this visually confirmed the allodidiploid
origin of
the tetraploid cottons
(Wendel et al., 2002). Besides, three pairs of crimson signals were detected only with the A
1-a
gDNA probe both in
(AD)
1
and (AD)
2
(Figure 1-c, f ), which were named “GISH-NORs”(Liu et al., 2005) , of which one in the A
sub-genome chromosomes (green arrows), and two in the D sub-genome chromosomes (white arrows), and it
significantly different from the A
1
and A
2
gDNA probes, the specific distributions about GISH-NORs were shown
in Table 1.
