Genetics & Molecular Biology

Scientific studies of why foods such as Brussels sprouts and stout beer are horribly bitter-tasting to some people but palatable to others are shedding light on a number of questions, from the mechanisms of natural selection to understanding how our genes affect our dietary habits.

Dr. Stephen Wooding, a population geneticist at UT Southwestern Medical Center in Dallas, studies how slight variations in genes give rise to variations in traits among a given human population.

Part of Dr. Wooding's research focuses on variations in the genes responsible for bitter-taste receptors, tiny receptacles on the tongue that intercept harsh-tasting chemicals from food.

Blurring boundaries

High up on the bluffs overlooking the Pacific Ocean in southern California, strange animals scurry about in their cages. They eat, drink, copulate and occasionally try to run away from human hands that enter their confined quarters. If you didn't know better, you would think they were ordinary mice. But these particular animals contain a hidden component not present in their naturally conceived cousins. Inside their brains are living human neurons that help them to see, hear and think.

The Allen Brain Atlas, a genome-wide map of the mouse brain on the Internet, has been hailed as “Google of the brain.” The atlas now has a companion or the brain’s working molecules, a sort of pop-up book of the proteins, or proteome map, that those genes express.

The protein map is “the first to apply quantitative proteomics to imaging,” said Richard D. Smith, Battelle Fellow at the Department of Energy’s Pacific Northwest National Laboratory, who led the mapping effort with Desmond Smith of UCLA’s David Geffen School of Medicine.


Caption: Abundance profiles of four different proteins compiled from 1 millimeter cubes (voxels) in a mouse brain.

For cells that hold so much promise, stem cells' potential has so far gone largely untapped. But new research from Rockefeller University and Howard Hughes Medical Institute scientists now shows that adult stem cells taken from skin can be used to clone mice using a procedure called nuclear transfer. The findings are reported in the Feb. 12 online edition of the Proceedings of the National Academy of Sciences.


Using a technique called nuclear transfer, mice were cloned using adult skin stem cells (right) and a more differentiated type of skin cell (left). The mouse on the right is almost two years old and the mouse on the right is one and a half.

Mice engineered to have cleft palates can be rescued in utero by injecting the mothers with a small molecule to correct the defect, say scientists at the Stanford University School of Medicine and Lucile Packard Children's Hospital. In addition to shedding light on the biology of cleft palate, the research raises hopes that it may one day be possible to prevent many types of human birth defects by using a similar vaccination-type technique in pregnant women likely to have affected fetuses.

"This is a really important baby step that opens the door to the development of fetal therapies," said pediatric craniofacial surgeon Michael Longaker, MD.

The first draft of the horse genome sequence has been deposited in public databases and is freely available for use by biomedical and veterinary researchers around the globe, leaders of the international Horse Genome Sequencing Project announced today.


Photo of Twilight the horse. NHGRI-supported researchers have sequenced the genome of this Thoroughbred mare from Cornell University in Ithaca, N.Y. (Courtesy of Doug Antzak, Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University)

Sucrose plays a vital role in coffee organoleptic quality. A team from CIRAD and the Agricultural Institute of Paraná in Brazil has recently identified the genes responsible for sucrose accumulation in coffee beans. This is a new step along the way to producing exceptional coffees.


The sucrose accumulated in the beans is one of the organoleptic compounds in coffee. (Photo Credit: Pierre Marraccini, CIRAD)

Many human proteins are not as good as they might be because the gene sequences that code for them have a double role which slows down the rate at which they evolve, according to new research published in PLoS Biology.

By tweaking these dual role regions, scientists could develop gene therapy techniques that produce proteins that are even better than those found in nature, and could one day be used to help people recover from genetic disorders.

The stretch of DNA which codes for a specific protein is often interrupted by sections of apparently useless DNA – known as introns – which need to be edited out in order to produce a new protein.


Before a transcribed gene is translated into t

If you bend a knee or an elbow, the nerves in your limbs stretch but do not break. A University of Utah study suggests why: A gene produces a springy protein that keeps nerve cells flexible. When the gene was disabled in tiny nematode worms, their nerve cells literally broke.


Nerve cells glow fluorescent green in these microscope photographs showing part of a cross section of a tiny nematode worm. The horizontal green linear feature near the bottom of each photo is the worm equivalent of the spinal cord, while a secondary nerve cord is the horizontal green line near the top.

The emerging picture of microbes as gene-swapping collectives demands a revision of such concepts as organism, species and evolution itself.

One of the most fundamental patterns of scientific discovery is the revolution in thought that accompanies a new body of data. Satellite-based astronomy has, during the past decade, overthrown our most cherished ideas of cosmology, especially those relating to the size, dynamics and composition of the Universe.

Similarly, the convergence of fresh theoretical ideas in evolution and the coming avalanche of genomic data will profoundly alter our understanding of the biosphere — and is likely to lead to revision of concepts such as species, organism and evolution.