A colorless world
Every so often I'm baffled by a graph, table, or other illustration in
the
New York Times: I can't
figure out what the scales are, what the numbers represent, etc.
Yesterday I was stumped by an elaborate illustration concerning
"genetic differentiation in modern humans", accompanying Nicholas Wade's
"
Humans Have Spread Globally, and Evolved Locally" in the
Science Times of 6/26/07, p.
3. This is a map of the world with icons (outline forms of human
beings) on it representing 52 modern human populations, each icon coded
for the makeup of the average genome for that population, with respect
to five "modern genetic clusters" (Africa, Eurasia, East Asia, Oceania,
America). The coding assigns a different shading for each
cluster, but I was able to pick out only one shading (for East Asian)
as distinguishable from the other four (by being noticeably
darker). The illustration was almost completely uninterpretable.
Then I realized what must have happened, and this morning I verified my
hypothesis.
The clue was a note pointing to a line on the map: "Blue lines show
ancestral human migrations, which formed the basis for modern
populations." There are indeed lines on the map, with arrowheads
suggesting the direction of migrations. But there are no
BLUE
lines; the entire illustration is in grayscale. Ah, I thought,
this illustration was supposed to be in color.
On the
Times website, it
is. African is yellow, Eurasian is blue, East Asian is red (and
darker than the other colors), Oceanian is green, and American is
purple, or at least a purplish blue. Some of the icons have
several colors, representing the makeup of the population in
question. There's a lot of information in that illustration, but
much of it depends on the colors.
Clearly, the illustration was meant to be in color, and there are a
number of other colored illustrations in this
Science Times, but somehow this one
escaped reproduction in color. Well, things go wrong.
zwicky at-sign csli period stanford period edu
Posted by Arnold Zwicky at June 27, 2007 10:43 AM
