NAME
Bio::Map::CytoPosition - Marker class with cytogenetic band storing attributes
SYNOPSIS
$m1 = Bio::Map::CytoPosition->new ( '-id' => 'A1',
'-value' => '2q1-3'
);
$m2 = Bio::Map::CytoPosition->new ( '-id' => 'A2',
'-value' => '2q2'
);
if ($m1->cytorange->overlaps($m2->cytorange)) {
print "Makers overlap\n";
}
DESCRIPTION
CytoPosition is marker (Bio::Map::MarkerI compliant) with a location in a cytogenetic map. See Bio::Map::MarkerI for more information.
Cytogenetic locations are names of bands visible in stained mitotic eucaryotic chromosomes. The naming follows strict rules which are consistant at least in higher vertebates, e.g. mammals. The chromosome name preceds the band names.
The shorter arm of the chromosome is called 'p' ('petit') and usually drawn pointing up. The lower arm is called 'q' ('queue'). The bands are named from the region separting these, a centromere (cen), towards the tips or telomeric regions (ter) counting from 1 upwards. Depending of the resolution used the bands are identified with one or more digit. The first digit determines the major band and subsequent digits sub bands: p1 band can be divided into subbands p11, p12 and 13 and p11 can furter be divided into subbands p11.1 and p11.2. The dot after second digit makes it easier to read the values. A region between ands is given from the centromere outwards towards the telomere (e.g. 2p2-5 or 3p21-35) or from a band in the p arm to a band in the q arm.
FEEDBACK
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AUTHOR - Heikki Lehvaslaiho
Email: heikki@ebi.ac.uk Address:
EMBL Outstation, European Bioinformatics Institute
Wellcome Trust Genome Campus, Hinxton
Cambs. CB10 1SD, United Kingdom
APPENDIX
The rest of the documentation details each of the object methods. Internal methods are usually preceded with a _
cytorange
Title : cytorange
Usage : $obj->cytorange();
Function:
Converts cytogenetic location set by value method into
an integer range. The chromosome number determines the
"millions" in the values. Human X and Y chromosome
symbols are represented by values 100 and 101.
The localization within chromosomes are converted into
values between the range of 0 and 200,000:
pter cen qter
|------------------------|-------------------------|
0 100,000 200,000
The values between -100,000 through 0 for centromere to
100,000 would have reflected the band numbering better but
use of positive integers was choosen since the
transformation is very easy. These values are not metric.
Each band defines a range in a chromosome. A band string
is converted into a range by padding it with lower and and
higher end digits (for q arm: '0' and '9') to the length
of five. The arm and chromosome values are added to these:
e.g. 21000 & 21999 (band 21) + 100,000 (q arm) + 2,000,000
(chromosome 2) => 2q21 : 2,121,000 .. 2,121,999. Note that
this notation breaks down if there is a band or a subband
using digit 9 in its name! This is not the case in human
karyotype.
The full algorithm used for bands:
if arm is 'q' then
pad char for start is '0', for end '9'
range is chromosome + 100,000 + padded range start or end
elsif arm is 'p' then
pad char for start is '9', for end '0'
range is chromosome + 100,000 - padded range start or end
Example : Returns : Bio::Range object or undef
Args : none
range2value
Title : range2value
Usage : $obj->range2value();
Function:
Sets and returns the value string based on start and end
values of the Bio::Range object passes as an argument.
Example :
Returns : string or false
Args : Bio::Range object
value
Title : value
Usage : my $pos = $position->value;
Function: Get/Set the value for this postion
Returns : scalar, value
Args : [optional] new value to set
numeric
Title : numeric
Usage : my $num = $position->numeric;
Function: Read-only method that is guarantied to return a numeric
representation for this position.
This instanse of the method can also be set, but you better
know what you are doing.
Returns : Bio::RangeI object
Args : optional Bio::RangeI object
See Bio::RangeI for more information.
chr
Title : chr
Usage : my $mychr = $position->chr();
Function: Get/Set method for the chromosome string of the location.
Returns : chromosome value
Args : [optional] new chromosome value