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May 31, 2009)
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21 May 2009 by Ewen
Callaway
This map depicts the
spread of HIV in
Enlarge image
HIV's European tour may
have begun in the
Sun-seeking tourists from
northern and central
The vast majority of the
study's participants said they acquired their infections in their home country,
so the patterns could be a vestige of HIV's emergence and early spread through
Europe in the early 1980s, probably after arriving from the
That's not certain,
though, and the patterns could also be a result of more recent transmissions,
says Dimitrios Paraskevis, a virologist at the University of Athens,
Greece, who led the study of viruses from 16 European countries and Israel. The
story is unclear because his team's analysis was not designed to pin a date to
the spread of HIV through
Paraskevis's team created
the map by sequencing parts of the HIV genome from viruses collected from 1337
people. Because the virus mutates as it spread through the continent, the
researchers were able to create an HIV "tree of life" that explains
how different strains relate to one another and hence tracks the virus's
European exploits.
If Mediterranean countries
were the major exporter of HIV, northern European countries turned out to be the
major importers. Strains collected from Austrians, Belgians and Luxembourgers
suggest the virus made mostly one-way trips to those countries.
The
A couple of other pathways
also emerged from the analysis. Many Danish viruses originated from
In future work, the
researchers will try to attach firmer dates to HIV's march through
Journal reference: Retrovirology,
in press
AFP May 28, 2009, 5:29 am
PARIS
(AFP) - In a controversial achievement, Japanese scientists announced on
Wednesday they had created the world's first transgenic primates, breeding
monkeys with a gene that made the animals' skin glow a fluorescent green.
The exploit opens up
exciting prospects for medical researchers, they said.
It could eventually lead
to lab monkeys that replicate some of humanity's most devastating diseases,
providing a new model for exploring how these disorders are caused and how they
may be cured.
"Great advances in
pre-clinical research can be expected using these models," the team said.
But other voices warned of
a potential ethics storm, brewed by fears that technology used on our closest
animal relatives could be turned to create genetically-engineered humans.
In a study published in
the British journal Nature, a team led by Erika Sasaki of the Central Institute
for Experimental Animals at
They introduced a foreign
gene, tucked inside a virus, into marmoset embryos that were then nurtured in a
bath of sucrose.
The gene codes for green
fluorescent protein (GFP), a substance that was originally isolated from a
jellyfish and is now commonly used as a biotech marker. An animal tagged with
GFP glows green when exposed to ultraviolet light, proving that a key gene
sequence has been switched on.
The transgenic embryos
were then implanted in the uterus of seven surrogate mother marmosets.
Three of recipients
miscarried. The other four gave birth to five offspring, all of which carried
the GFP gene.
In two of these five, the
GFP gene had been incorporated into the reproductive cells. A second generation
of marmosets was then derived from one of the two.
The work is important,
because medical researchers have hankered for an animal model that is closer to
the human anatomy than rodents.
Mice and rats, genetically
engineered to have the symptoms of certain human diseases, are the mainstay of
pre-clinical lab work, in which scientists test their theories before trying out
any outcome on human volunteers.
But many disorders,
especially neurological diseases such as Alzheimer's and Parkinson's, are so
complex that they cannot be reproduced meaningfully in rodents because their
biology is different.
Hopes for a non-human
primate model have until now been dashed by the failure to insert a gene into a
monkey's sperm and eggs -- the "germline" that ensures that the
inserted DNA is passed on to future generations rather than lost.
The first
genetically-modified monkey was born in 2000. Known as ANDi (the initials of
"Inserted DNA," spelt backwards), the rhesus carried the GFP gene but
not in its reproductive cells.
The latest exploit thus
opens up hopes of eventually breeding colonies of transgenic primates with
inherited traits that closely replicate human disease.
"This is the first
case ever established in the world that an introduced gene was successfully
inherited (by) the next generation in primates," the researchers said in a
press relase.
Future plans include
creating transgenic marmosets that replicate human diseases such as Parkinson's
and amyotrophic lateral sclerosis.
In a commentary also
published by Nature, Gerald Schatten and Shoukhrat Mitalipov, primate research
specialists in the
They said marmosets were
not as useful as baboons or rhesus monkeys in replicating some diseases, notably
HIV and tuberculosis.
Another question was the
random insertion of a foreign gene in the monkey's genetic code. This may have
caused some of the miscarriages and, if previous research is a guide, could
unleash cancer.
Scientists also have to
address legitimate public concern about animal welfare and the need for
"realistic policies" to prevent genetically-engineered babies, they
warned.
"There are many
unanswered questions," Helen Wallace, of GeneWatch
"It's a big step from
making a fluorescent green marmoset to making a marmoset that replicates a human
disease, it's a much more complicated thing to do.
"There's also a very
important ethical debate, firstly about the animals themselves and secondly
about what this might lead to in the future, whether it might be ethically
justified to genetically engineer humans."