all genetics stories

Molecular analysis confirms T. Rex's evolutionary link to birds

yvette — Mon, 21 Apr 2008 16:25:39 -0400

Putting more meat on the theory that dinosaurs' closest living relatives are modern-day birds, molecular analysis of a shred of 68-million-year-old Tyrannosaurus rex protein -- along with that of 21 modern species -- confirms that dinosaurs share common ancestry with chickens, ostriches, and to a lesser extent, alligators.

A Genetic Cause for Iron Deficiency

yvette — Wed, 09 Apr 2008 17:07:01 -0400

The discovery of a gene for a rare form of inherited iron deficiency may provide clues to iron deficiency in the general population – particularly iron deficiency that doesn’t respond to iron supplements. The finding was published online by the journal Nature Genetics on April 13.

Chromosomal abnormality linked to autism disorders

404132862 — Wed, 09 Jan 2008 17:04:29 -0500

Researchers have fitted another piece into the complex genetic puzzle that is autism, finding DNA deletions and duplications on a specific chromosome that they say explains one to two percent of the 1.5 million cases of autism and related disorders in the United States today.

The genetic changes were discovered in DNA scans of more than 3,000 people, both with and without autism spectrum disorder, a category of developmental disability that includes autism disorder, Asperger’s syndrome, and a broad category called “pervasive developmental disorder not otherwise specified.”

Gene variation may elevate risk of liver tumor in patients with cirrhosis

404132862 — Mon, 31 Dec 2007 09:13:02 -0500

A genetic variation appears to significantly increase the risk that individuals with cirrhosis of the liver will develop hepatocellular carcinoma (HCC), a liver tumor that is the third leading cause of cancer death.

Massive decoding effort reveals fruit fly DNA

404132862 — Wed, 07 Nov 2007 12:13:51 -0500

An enormous effort to decode the DNA of one of the most important laboratory animals — the fruit fly — ended in success this week as a collaboration of researchers from 16 nations announced the sequencing of 10 fly species’ genomes.

The research allows the extraordinary side-by-side comparison of the DNA of 12 species of fruit flies — two had already been decoded — as scientists search to understand the workings of individual genes and how those genes translate into specific physical characteristics.

Researchers track down rheumatoid arthritis gene

404132862 — Mon, 05 Nov 2007 10:03:31 -0500

Researchers at Brigham and Women’s Hospital (BWH) and the Broad Institute of MIT and Harvard have discovered a gene involved in rheumatoid arthritis, a painful autoimmune disease that affects 2.1 million Americans and can destroy cartilage and bone within the afflicted joint.

Study paints genetic portrait of lung cancer

404132862 — Mon, 05 Nov 2007 11:37:32 -0500

An international team of scientists today announced the results of a systematic effort to map the genetic changes underlying lung cancer, the world’s leading cause of cancer deaths.

Appearing in the November 4 advance online issue of the journal Nature, the research provides a comprehensive view of the abnormal genetic landscape in lung cancer cells, revealing more than 50 genomic regions that are frequently gained or lost in human lung tumors. While one-third of these regions contain genes already known to play important roles in lung cancer, the majority harbor new genes yet to be discovered.

Scientists synthesize memory in yeast cells

404132862 — Sun, 16 Sep 2007 15:03:55 -0400

Harvard Medical School (HMS) researchers have successfully synthesized a DNA-based memory loop in yeast cells, an experiment that marks a significant step forward in the emerging field of synthetic biology.

After constructing genes from random bits of DNA, researchers in the lab of Pamela Silver, a faculty member in Harvard Medical School’s Department of Systems Biology, not only reconstructed the dynamics of memory, but also created a mathematical model that predicted how such a memory “device” might work.

First robust genetic link to height in humans identified

404132862 — Thu, 06 Sep 2007 11:55:03 -0400

Over a century ago, scientists first proposed that height is a complex trait — one influenced by environmental factors and multiple genes. While subsequent studies revealed that most of the variation in adult height is genetically determined, there has been little success in pinpointing the responsible genes. Some clues have come from rare syndromes of extreme height or shortness caused by severe alterations in specific gene sequences, but by and large, these changes do not explain the normal spectrum of human height.

Scientists have something to chew on

50443248 — Mon, 01 Oct 2007 16:20:15 -0400

In a groundbreaking study, two Harvard scientists have for the first time extracted human DNA from ancient artifacts. The work potentially opens up a new universe of sources for ancient genetic material, which is used to map human migrations in prehistoric times.

Before this, archaeologists could only get ancient DNA from relics of the human body itself, including prehistoric teeth, bones, fossilized feces, or — rarely — preserved flesh. Such sources of DNA are hard to find, poorly preserved, or unavailable because of cultural and legal barriers.

By contrast, the genetic material used in the Harvard study came from two types of artifacts — 800 to 2,400 years old — that are found by the hundreds at archaeological sites in the American Southwest.

Opossum genome shows 'junk' DNA source of genetic innovation

50443248 — Wed, 09 May 2007 16:51:38 -0400

A tiny opossum's genome has shed light on how evolution creates new creatures from old, showing that change primarily comes by finding new ways of turning existing genes on and off.

The research, by an international consortium led by the Broad Institute of MIT and Harvard, revises our understanding of genetic evolution. Scientists previously thought that evolution slowly changed the genes that create specific proteins. As the proteins changed, so did the creatures that owned them.

The current research shows that opossum and human protein-coding genes have changed little since their ancestors parted ways, 180 million years ago. It has been the regulation of their genes - when they turn on and off - that has changed dramatically.

"Evolution is tinkering much more with the controls than it is with the genes themselves," said Broad Institute director Eric Lander. "Almost all of the new innovation ... is in the regulatory controls. In fact, marsupial mammals and placental mammals have largely the same set of protein-coding genes. But by contrast, 20 percent of the regulatory instructions in the human genome were invented after we parted ways with the marsupial."

The research, released May 9 also illustrated a mechanism for those regulatory changes. It showed that an important source of genetic innovation comes from bits of DNA, called transposons, that make up roughly half of our genome and that were previously thought to be genetic "junk."

The research shows that this so-called junk DNA is anything but, and that it instead can help drive evolution by moving between chromosomes, turning genes on and off in new ways.

Researchers develop ALS mouse stem cell line

90581724 — Fri, 20 Apr 2007 14:54:20 -0400

A team of Harvard researchers has used embryonic stem cells, derived from mice carrying a human gene known to cause a form of amyotrophic lateral sclerosis (ALS), to create an in vitro model of the always-fatal neurodegenerative disease. Harvard Stem Cell Institute principal investigator Kevin Eggan and Tom Maniatis, the Thomas H. Lee Professor of Molecular and Cellular Biology in Harvard's Faculty of Arts and Sciences, are the senior authors of the study published on-line April 15 by Nature Neuroscience.

Manipulating genetic switch in mice eases MD symptoms

Tue, 10 Jul 2007 15:57:40 -0400

Scientists at Dana-Farber Cancer Institute have shown in a laboratory study that revving up a crucial set of muscle genes counteracts the damage caused by a form of muscular dystrophy.

Reporting in the April 1 issue of Genes and Development, the researchers demonstrated that manipulating a genetic molecular switch increased the genes’ activity in the muscles of mice with Duchenne muscular dystrophy, slowing the disease-associated muscle wasting. The authors caution that they have not yet found a way to tweak the switch, known as PGC-1alpha, in humans.

Viruses get the silent treatment, any disease is a target

Wed, 11 Jul 2007 10:41:57 -0400

What do you do if you're sure you've found a way to knock out the AIDS virus but you can't get the medicine into infected cells? That was the problem faced by Judy Lieberman, a professor of pediatrics at Harvard Medical School.

Using tiny bits of genetic material, she and her research team have blocked messages sent from genes that underlie diseases like genital herpes and hepatitis. "We used the technique to protect mice against liver failure," she says. "Eighty percent of the protected animals lived; 80 percent of those without the protection died."

Practical way to target cancer cell mutations demonstrated

Wed, 11 Jul 2007 11:53:45 -0400

A study led by researchers at Dana-Farber Cancer Institute and Broad Institute of the Massachusetts Institute of Technology and Harvard University provides the first demonstration of a practical method of screening tumors for cancer-related gene abnormalities that might be treated with "targeted" drugs.

The findings, published online Feb. 11 on the Nature Genetics Web site, may help relieve a bottleneck between scientists' expanding knowledge of the genetic mutations associated with cancer and the still-nascent ability of doctors to use that knowledge to benefit patients. The results constitute an important step toward the era of "personalized medicine," in which cancer therapy will be guided by the particular set of genetic mutations within each patient's tumor, the authors suggest.

"It's universally recognized that cancer is a disease of the genome, of mutations within genes responsible for cell growth and survival, and a great deal of effort has gone into finding those mutations, to the point where several hundred to a thousand are now known," said the study's senior author, Levi Garraway, of Dana-Farber and the Broad Institute. "The challenge has been how to determine which of them are involved in each of the hundreds of kinds of cancer that occur in humans - and to develop accurate, affordable methods of detecting key mutations in tumor samples. This study suggests that such a method is feasible on a large scale."

The authors took advantage of a scientific serendipity to devise a simple test to detect important cancer mutations. Mutations in oncogenes (genes linked to cancer) do not occur randomly; rather, they seem to arise most frequently in certain regions of the oncogenes. As a result, researchers didn't necessarily have to scan the entire length of each gene, but could focus instead on the sections most likely to harbor mutations.

Major funding for the study was provided by grants from Genentech, Inc. the American Cancer Society, the National Cancer Institute, the Prostate Cancer Foundation, the Burroughs-Wellcome Fund, the Robert Wood Johnson Foundation, and the Novartis Institute for Biomedical Research.