April 13, 2005
The New York Times
By Nicholas Wade
A five-year project to reconstruct a genealogy of the world's populations
and the migration paths of early humans from their ancestral homeland in
Africa will be started today by the National Geographic Society and I.B.M.,
the society said in a statement.
The goal of the program is to collect 100,000 blood samples from indigenous
populations around the world and analyze them genetically. Researchers at 10
local centers and at the National Geographic Society in Washington will then
assign the people who give blood to lineages that trace the routes traveled
by their early ancestors.
The program is an effort to accomplish the goals of the Human Genome
Diversity Project, an initiative that was proposed by population geneticists
in 1991.
That project ran into a political furor that prevented it from receiving
substantial government support. It was denounced by some cultural
anthropologists, who said that looking for genetic differences among
populations was tantamount to racism. And advocates for indigenous peoples
portrayed it as a "vampire project" for extracting valuable medical
information from the blood of endangered tribes while giving nothing in
return.
The proponents viewed their plan as complementing the Human Genome Project,
then getting under way, because it would show how the sequence of DNA units
in the human genome varied from one population to another. The project did
proceed on a more modest basis, eventually collecting blood samples from 52
populations that were converted into 1,000 cell lines. The first major
analysis, published in 2002, showed that the subjects' genomes fell into
five major clusters corresponding to their continent of origin and, in
effect, to their race.
This and many other studies have established that the branches of the human
family tree on different continents coalesce to a single root, the ancestral
human population that began to migrate from northeast Africa some 50,000
years ago. The routes of this migration are known in general outline but
many details remain to be filled in.
The National Geographic's program, if it succeeds, will create a collection
of blood samples 100 times larger than the Human Genome Diversity Project
did. Dr. Spencer Wells, a population geneticist at the society who is
leading the program, said he hoped to head off charges of exploitation by
offering money to the tribes for education and cultural preservation.
Many indigenous peoples believe their ancestors have always lived in their
home territory, a credo that will not be supported by genetic analysis of
their blood samples. Dr. Wells said that he would "tell people up front"
that some of the results may contradict what they believe. "The idea that we
have all come on a journey from a common origin is intriguing to people," he
said.
The program will cost at least $40 million over five years, a National
Geographic Society spokeswoman said. Sources of support include the Waitt
Family Foundation of San Diego and the income expected from members of the
public, who will be encouraged to send in cheek swabs and learn for $99.95
which male or female lineage they belong to.
Male lineages, based on the Y chromosome, and female lineages, based on
mitochondrial DNA, are mostly confined to specific continents, reflecting
the fact that until recently people mostly lived and procreated in the place
they were born.
Dr. Luca Cavalli-Sforza, the Stanford University population geneticist who
was a leading proponent of the Human Genome Diversity Project, said the
National Geographic effort would "be a major addition to our knowledge." Dr.
Cavalli-Sforza, a pioneer of population genetics, is an adviser to the
program.
But Dr. Kenneth Kidd, a population geneticist at Yale University, expressed
reservations about the plan to preserve the blood samples as raw DNA.
Because the DNA is finite, it cannot be shared with every scientist who may
ask for some. In the Human Genome Diversity Project, by contrast, white
blood cells from a sample were made essentially immortal before storage.
Though it would cost an additional $200 to $300 to immortalize each sample,
the cells last forever and the supply is inexhaustible.
The National Geographic program will develop a lot of useful information
"but to me it is not a properly and fully developed kind of study" because
the samples cannot be made available to everyone in the scientific
community, Dr. Kidd said.
Dr. Wells said a large amount of DNA would be available from the 5 to 10
milliliters of blood drawn in each sample. He cited the extra cost of making
permanent cell lines and also said that some indigenous peoples opposed the
notion of having their cells live on after their deaths.
Besides tracing the routes of early human migrations, the National
Geographic program will study other questions of population history like the
origin of the Han Chinese, the lost homeland of the Indo-European languages
and whether a genetic trail was left by the armies of Alexander the Great.