November 11, 2005
POPULATION GENETICS: Genetic Road Map Drawn
for Tracing Route to Common Diseases
The Human Genome Project revealed the 99.9 percent of DNA shared among all
people. But scientists believe that the crucial clues to health and disease
are found in the slight genetic differences that make family history one of
the strongest risk factors for all diseases. Genes and other DNA are inherited
in mostly unchanging blocks, called haplotypes, that are flanked by hotspots
of genetic recombination. In the Oct. 27 Nature, David Altshuler and colleagues
including (left to right) Stephen Schaffner, Pardis Sabeti, and Paul de Bakker
report the first rough guide to haplotype variations in a resource called the
HapMap. Researchers believe the map will speed discovery of genetic differences
that predispose people to particular diseases.
NEUROSCIENCE: Drug May Cause Weight Loss Through
Brain Cell Growth
A surprising new study suggests that an experimental drug leads to long-term
weight loss by spurring growth of new brain cells. The research, led by Jeffrey
Flier, found that mice treated with the drug sprouted these cells in a region
of the brain that controls energy balance. The results, published in the Oct.
28 Science, draw a provocative connection between brain plasticity and the regulation
of a seemingly hard-wired function of the brain.
Skin Cells Engineered to Mimic Thymus in Producing Mature T Cells
Immune T cells are born and educated in the specialized surroundings of the thymus,
a complex environment that researchers have long sought to replicate in the lab.
Now, by adapting easily obtained skin cells as a stand-in for the thymus, Thomas
Kupper and Rachael Clark have designed a three-dimensional living factory that
generates mature, functional human T cells from bone marrow stem cells. Their
technique, described in the Nov. 1 Journal of Clinical Investigation, offers
for the first time a practical method for creating human T cells that could one
day be used therapeutically to boost a patient’s immune system after bone
marrow transplantation or to fight cancer or HIV.
Copyright 2005 by the President and Fellows of Harvard College