staden-lg/help/GIP.RNO

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2021-12-04 13:07:58 +08:00
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GIP
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.PARA
A digitizer is
a two dimensional surface
which is such that if a special pen is pressed onto it, the pens
coordinates can be recorded by a computer.
These coordinates
can be interpreted by a program.
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The digitizing device we use works by the pen emitting a high frequency
sound which is picked up by two microphones positioned at the rear of the
working area. The pen position is determined by triangulation and the
digitizing device sends the coordinates to the computer. As no special
surface is required the device can conveniently be positioned on a light
box giving the sequencer an unobscured view of the autoradiographs.
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The digitizer
is called a GRAPHBAR MODEL GP7 made by
Science Accessories Corp,
970 Kings Highway West,
Southport,
Connecticut 06490,
USA.
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The program uses a menu to allow the user to select commands or
to enter the uncertainty codes for areas of the gel that are
difficult to interpret. A menu is simply a series of boxes drawn on
the digitizing surface that each contain a command or
uncertainty code. When the user puts the pen down in these special
regions the program interprets the coordinates as commands and acts
appropriately. A copy of the menu should have been sent to you.
It should be stuck down on the surface of the
light box in the digitizing area. For convenience it is best to position it
to the right of the digitizing area, but in practice as long as
its top
edge is parallel to the digitizer box, it can be put anywhere in the active
region.
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Entering gel readings using a digitizer
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The autoradiograph should be stuck down on the light box with the lanes
running, as near is as
possible, at right angles to the digitizer. To read
an autoradiograph placed on the light box
the user need only define the positions of
the four sequencing lanes and the bases
to which they correspond and then use the pen to point to each
successive band progressing up the gel. The program examines the
coordinates of each pen position to see in which of the four
lanes
it lies and assigns the corresponding base to be stored in the
computer. Each time the pen tip is depressed to point to a position
on the surface of the digitizer the program sounds the bell on the
terminal (a different sound for each of the four bases on the
microcomputer version of the program)
to indicate to the user that a point has been recorded. As
the sequence is read the program displays it on the screen.
.para
The program uses a menu
to allow the user to select commands or
to enter the uncertainty codes for areas of the gel that are
difficult to interpret. A menu is simply a series of boxes drawn on
the digitizing surface that each contain a command or
uncertainty code. When the user puts the pen down in these special
regions the program interprets the coordinates as commands and acts
appropriately. As well as the uncertainty codes
A,C,G,T,1,2,3,4,B,D,H,V,R,Y,X,-,5,6,7,8 the following commands are
included in the menu: DELETE removes the last character from
the sequence;
RESET allows the lane centres to be redefined;
START means begin the next
stage of the procedure; STOP means stop the current stage in the
procedure; CONFIRM means confirm that the last command or set of
coordinates are correct.
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The digitizing device also has a menu of its own. This lies in a two inch wide
strip immediately in front of the digitizing box. Pen positions within this
two inch strip are interpretted as commands to the digitizer and are not
sent to the GIP program. In general the only time users will need to use
the device menu is when they tell GIP where the program menu lies in the
digitizing area. This is done by first hitting ORIGIN in the device menu
and then hitting the bottom left hand corner of the program menu. The
program menu can hence be positioned anywhere in the active region but
should be arranged parallel to the digitizer.
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The user should try to hit the bands as near as possible to the centre of
the lanes because the program tracks the lanes up the film using the pen
positions. By using this tracking strategy the user only has to define the
centres of the bottom of the lanes before starting to read the film. The
program can correctly follow quite curved lanes and constantly checks that
its lane centre coordinates look sensible. If the lane centres appear to be
getting too close the program stops responding to the pen positions of
bands and hence does not ring the bell. If this occurs users must hit the
reset box in the menu and the program will request them to redefine the
lane centres at the current reading position. Then they can continue
reading. As a further safeguard the program will only respond to pen
positions either in the menu or very close to the current reading position.
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Running the gel reading program
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The autoradiograph should be firmly stuck down on the light box and the
program started by typing GIP. It will ask the first question.
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" ? FILE OF FILE NAMES="
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Type the name for the file of file names and then follow the instructions.
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" HIT DIGITIZER MENU ORIGIN"
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" THEN PROGRAM MENU ORIGIN"
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" THEN HIT START IN PROGRAM MENU"
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If the bell does not sound after you hit start try hitting metric in the
device menu (the program uses metric units, and some digitizers are set to
default to use inches; hitting metric switches between the two).
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After the bell has sounded the program will give the default lane order.
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" LANE ORDER IS T C A G"
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" IF CORRECT HIT CONFIRM, ELSE HIT RESET"
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If the lane order, reading from left to right is correct hit confirm in the
program menu. If you are using a different order hit reset and you will be
asked to define the lane order from left to right using the program menu
(as follows).
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" DEFINE LANE ORDER (LEFT TO RIGHT) USING MENU"
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Hit the boxes in the menu that contain the symbols A,C,G,T in the
left-right order of the lanes. The program will respond with the lane order
as above and ask for confirmation. When this is received, the next task is
to define the start positions of the next four lanes.
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" HIT START, THEN HIT (LEFT TO RIGHT)"
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" THE START POSITIONS FOR THE NEXT FOUR LANES"
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Hit the centres of the four lanes at a height level with the first band
that is going to be read. The program will report the mean lane separations
and asks for confirmation that they are correct.
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" MEAN LANE SEPARATION IS XX"
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" HIT CONFIRM TO CONTINUE"
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Users will become familiar with the values from their films and will spot
any unusual numbers.
Asking for confirmation allows users to try again if they had made a
mistake, but generally the lane separation values can be ignored.
Hit confirm, and the program will give the message
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" HIT START WHEN READY TO BEGIN READING"
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Hit start and the program will give the message
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" HIT BANDS, UNCERTAINTY CODES, RESET OR STOP"
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Hit the bands, interpretting the sequence progressing
up the film. If necessary use the uncertainty codes. If the pen stops
responding hit reset and follow the instructions as above. When the
sequence becomes unreadable hit stop and the program will ask for a file
name for the gel reading just read.
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" ? FILE NAME FOR THIS GEL READING="
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Type the file name observing the rules about legal gel readings names.
The program will ask if you wish
to read another sequence.
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" TO ENTER ANOTHER GEL READING TYPE 1"
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To enter another type 1 and you will be back to the step of defining the
lane order. Typing anything else will stop the program.
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Running the microcomputer version of the gel reading program
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The microcomputer version of GIP is slightly different and is called
GIPB. The BBC micro
does not have the capacity to process the gel readings beyond the reading
stage.
This means that users of this program
would need to transfer their gel readings from the micro to another machine
using a terminal emmulator. Transferring many files is tedious and so the
microcomputer version of the gel reading program stores all the gel
readings for each run of the program in a single file. This special
file contains both sequences and file names and can be moved in a single
transfer to another machine. Once on the other machine the single file must
be split into separate gel reading files and a file of file names. This is
done using the program BSPLIT. As far as using the microcomputer version
of GIP, the only difference is that the first file name the program
requests is not a file of file names, but a name for the single file to
contain all the gel readings and their names.