How do I add lines connecting corresponding boxes, that I've drawn on a plot? (MATLAB) - matlab

Question

I have a matrix (Data) which looks like this:
(start) (stop) (strand) (gene number)
[ 1 29 1 1]
[ 32 38 1 1]
[ 44 60 1 1]
[ 66 70 0 2]
[ 75 80 0 2]
[ 81 88 0 3]
[ 99 102 0 3]
[ 111 160 0 3]
[ 166 170 1 4]
[ 171 188 1 4]
which I have plotted onto a graph using the first two columns as X positions, and a set Y position. This is the code I have up till now:
if nargin<4, strands = 0; end;
if nargin<3, height = 0.1; end;
if nargin<2, y = 2.1; end;
for k=1:size(cds,1),
xc = [cds(k,1) cds(k,2) cds(k,2) cds(k,1)];
if strands,
if cds(k,3), % minus strand
yc = [y y y-height/2 y-height/2];
c = 'r';
else % plus strand
yc = [y+height/2 y+height/2 y y];
c = 'b';
end
else
yc = [y+height/2 y+height/2 y-height/2 y-height/2];
c = 'b';
end
h(k) = patch(xc,yc,c);
end
What I'm trying to do is add lines underneath each 'box' which corresponds to the gene number (4th collumn of the data matrix). How would I go about doing this with the plot function?

Answer 1

It's not clear from your question how you want the lines to indicate the gene numbers, I assume you want different colors for each type. Here is how I would do it:
cds = [
1 29 1 1
32 38 1 1
44 60 1 1
66 70 0 2
75 80 0 2
81 88 0 3
99 102 0 3
111 160 0 3
166 170 1 4
171 188 1 4
];
strands = 0;
height = 0.1;
y = 2.1;
[g,gIdx,gNum] = unique(cds(:,4));
clr = 'gcmykrb';
for k=1:size(cds,1),
xc = [cds(k,1) cds(k,2) cds(k,2) cds(k,1)];
if strands,
if cds(k,3), % minus strand
yc = [y y y-height/2 y-height/2];
c = 'r';
else % plus strand
yc = [y+height/2 y+height/2 y y];
c = 'b';
end
else
yc = [y+height/2 y+height/2 y-height/2 y-height/2];
c = 'b';
end
h(k) = patch(xc,yc,c);
hLine(k) = line([cds(k,1) cds(k,2)], [y-3*height/4 y-3*height/4], ...
'LineWidth',5, 'Color',clr(gNum(k)));
end
legend(hLine(gIdx), num2str(g), 'Orientation','horizontal')