Lineages Through Time Plot
These functions provide tools for plotting the numbers of lineages through time from phylogenetic trees.
ltt.plot(phy, xlab = "Time", ylab = "N", backward = TRUE, tol = 1e-6, ...) ltt.lines(phy, backward = TRUE, tol = 1e-6, ...) mltt.plot(phy, ..., dcol = TRUE, dlty = FALSE, legend = TRUE, xlab = "Time", ylab = "N", log = "", backward = TRUE, tol = 1e-6) ltt.coplot(phy, backward = TRUE, ...) ltt.plot.coords(phy, backward = TRUE, tol = 1e-6, type = "S")
phy |
an object of class |
xlab |
a character string (or a variable of mode character) giving the label for the x-axis (default is "Time"). |
ylab |
idem for the y-axis (default is "N"). |
backward |
a logical value: should the time axis be traced from the present (the default), or from the root of the tree? |
tol |
a numeric value (see details). |
... |
in the cases of |
dcol |
a logical specifying whether the different curves should
be differentiated with colors (default is |
dlty |
a logical specifying whether the different curves should
be differentiated with patterns of dots and dashes (default is
|
legend |
a logical specifying whether a legend should be plotted. |
log |
a character string specifying which axis(es) to be
log-transformed; must be one of the followings: |
type |
either |
ltt.plot
does a simple lineages through time (LTT)
plot. Additional arguments (...
) may be used to change, for
instance, the limits on the axes (with xlim
and/or
ylim
) or other graphical settings (col
for the color,
lwd
for the line thickness, lty
for the line type may be
useful; see par
for an exhaustive listing of
graphical parameters). The y-axis can be log-transformed by
adding the following option: log = "y"
.
The option tol
is used as follows: first the most distant tip
from the root is found, then all tips whose distance to the root is
not different from the previous one more than tol
are
considered to be contemporaneous with it.
If the tree is not ultrametric, the plot is done assuming the tips, except the most distant from the root, represent extinction events. If a root edge is present, it is taken into account.
ltt.lines
adds a LTT curve to an existing plot. Additional
arguments (...
) may be used to change the settings of the added
line.
mltt.plot
does a multiple LTT plot taking as arguments one or
several trees. These trees may be given as objects of class
"phylo"
(single trees) and/or "multiPhylo"
(multiple
trees). Any number of objects may be given. This function is mainly
for exploratory analyses with the advantages that the axes are set
properly to view all lines, and the legend is plotted by default. The
plot will certainly make sense if all trees have their
most-distant-from-the-root tips contemporaneous (i.e., trees with only
extinct lineages will not be represented properly). For more flexible
settings of line drawings, it may be better to combine
ltt.plot()
with successive calls of ltt.lines()
(see
examples).
ltt.coplot
is meant to show how to set a tree and a LTT plots
on the same scales. All extra arguments modify only the appearance of
the tree. The code can be easily edited and tailored.
ltt.plot.coords
returns a two-column matrix with the time
points and the number of lineages, respectively.
type = "S"
returns the number of lineages to the left of (or "up to")
the corresponding point in time, while type = "s"
returns the number of
lineages to the right of this point (i.e, between that time and the next).
Emmanuel Paradis
Harvey, P. H., May, R. M. and Nee, S. (1994) Phylogenies without fossils. Evolution, 48, 523–529.
Nee, S., Holmes, E. C., Rambaut, A. and Harvey, P. H. (1995) Inferring population history from molecular phylogenies. Philosophical Transactions of the Royal Society of London. Series B. Biological Sciences, 349, 25–31.
kronoviz
, skyline
, LTT
,
branching.times
, birthdeath
,
bd.ext
, yule.cov
, bd.time
;
plot
for the basic plotting function in R
data(bird.families) opar <- par(mfrow = c(2, 1)) ltt.plot(bird.families) title("Lineages Through Time Plot of the Bird Families") ltt.plot(bird.families, log = "y") title(main = "Lineages Through Time Plot of the Bird Families", sub = "(with logarithmic transformation of the y-axis)") par(opar) ### to plot the tree and the LTT plot together data(bird.orders) layout(matrix(1:4, 2, 2)) plot(bird.families, show.tip.label = FALSE) ltt.plot(bird.families, main = "Bird families") plot(bird.orders, show.tip.label = FALSE) ltt.plot(bird.orders, main = "Bird orders") layout(1) ### better with ltt.coplot(): ltt.coplot(bird.families, show.tip.label = FALSE, x.lim = 27.5) data(chiroptera) chiroptera <- compute.brlen(chiroptera) ltt.coplot(chiroptera, show.tip.label = FALSE, type = "c") ### with extinct lineages and a root edge: omar <- par("mar") set.seed(31) tr <- rlineage(0.2, 0.15) tr$root.edge <- 5 ltt.coplot(tr, show.tip.label = FALSE, x.lim = 55) ## compare with: ## ltt.coplot(drop.fossil(tr), show.tip.label = FALSE) layout(1) par(mar = omar) mltt.plot(bird.families, bird.orders) ### Generates 10 random trees with 23 tips: TR <- replicate(10, rcoal(23), FALSE) ### Give names to each tree: names(TR) <- paste("random tree", 1:10) ### And specify the class of the list so that mltt.plot() ### does not trash it! class(TR) <- "multiPhylo" mltt.plot(TR, bird.orders) ### And now for something (not so) completely different: ltt.plot(bird.orders, lwd = 2) for (i in 1:10) ltt.lines(TR[[i]], lty = 2) legend(-20, 10, lwd = c(2, 1), lty = c(1, 2), bty = "n", legend = c("Bird orders", "Random (coalescent) trees"))
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