Biology Reference
In-Depth Information
a
b
YBL091C-A
YNL162W
40
160
1
120
30
1
6
80
20
6
40
10
0
0
0
5
10
15
2
0
0
100
200
300
-40
TL
TL
c
d
YHR029C
YLR084C
2
25
6
1
20
1.5
15
1
10
1
0.5
5
6
0
0
0
20
40
60
80
0
10
20
30
4
0
-5
TL
TL
Fig. 12.6 The “TL-TR phase diagram”: The plots of the transcription rates (TR) against transcript
levels (TL) (in arbitrary units) measured in budding yeast at six time points (
1
¼
0 min,
2
850 min) after the
glucose-galactose shift. Each point represents the average of triplicate measurements (Garcia-
Martinez et al. 2004). The plotted genes were randomly chosen out of the 5,725 genes showing no
missing values in their triplicate measurements of TL and TR. The notation given on the
top
of
each figure is the name of the open reading frame (ORF) whose transcript was measured
¼
5 min,
3
¼
120 min,
4
¼
360 min,
5
¼
450 min, and
6
¼
et al. (2002) and Garcia-Martinez et al. (2004) - measured both TL (transcript
level
)
and TR (transcription
rates
) simultaneously using DNAmicroarrays. Examples of the
TL and TR data obtained by the latter group from budding yeast subjected to
the glucose-galactose shift are presented in Fig.
12.6
, which may be referred to as
the “TL-TR phase diagram.”
It is clear that TL and TR do not always change in parallel as most workers in the
field have been assuming. The following quotations are typical of over 50 randomly
selected papers that have been examined:
Microarrays prepared by high-speed robotic printing of complementary DNAs on
glass were used for quantitative expression measurements of the corresponding
genes
...
(Schena et al. 1995). (12.6)
Oligonucleotide arrays can provide a broad picture of the state of the cell, by monitoring the
expression level of thousands of
genes
at the same time
...
(Alon et al. 1999). (12.7)
DNA microarrays, permits the simultaneous monitoring of thousands of
genes
...
(White et al. 1999).
(12.8)
DNA microarrays are used to monitor
changes in gene expression levels
...
expression is
estimated by comparing the
relative amount of mRNA
in two distinct cell populations
.
...
