Source- ABC News

10/29/02

Single Cell DNA Testing in Forensics

An Australian scientist has refined individual identification by forensic DNA testing to only one cell. The usual procedure requires at least 200 to 500 cells to gain similar level of accuracy.

The researcher, Dr. Finley, said that his new technique is much faster than current testing. This will allow testing of thousands of cells every day. In addition, Finley said that the ability to identify accurately DNA from only one cell means that unsolved crime cases may now be solved using his technique.

The technique can pick up enough DNA material from a single flake of dandruff or a skin cell dating back 30 years or even decades or centuries.

Scientific validation of this new technique will require at least three to five years.

Source- NY Times

10/18/02

Crops With Altered Genes for Allergens

Using genetic engineering, a group of scientists in Australia has worked on removing allergens from ryegrass, a major cause of hay fever. Another group in Hawaii has altered the genetic makeup of soybeans to free it from allergens. And at least two groups are attempting to genetically engineer the deadly ricin toxin out of castor plants.

Pioneer Hi-Bred International, the company that is growing the less allergenic soybean in Hawaii , is claiming that it might take 7 to 10 years to reach the market.

"The ultimate goal is to make foods more safe so ingestion of hidden allergens will not cause anaphylactic or dangerous food reactions," said Dr. Helm, who is working on the soybean.

Genetic engineering can be used to knock out the genes responsible for producing the allergenic proteins. One way to do this is by putting in a backward copy of the gene in question, so it inactivates the plant's own gene. Another way is to put in an extra normal copy of the gene, which sometimes stimulates the plant to shut down both the inserted gene and its own.

The scientists working on the soybean, removed a protein, P34, that is the cause for about 65 percent of the plant's allergenicity. P34 is only one of three major allergens in soy; the next step will be to get rid of the other two allergens.

Two small biotech companies, Arcadia BioSciences of Phoenix and Anawah Inc. of Seattle , have collaborated to identify and remove the genes for ricin toxin from castor plants. In addition, the Agriculture Department is working on removing both ricin and an allergen in castor plants. Ricin is one of the deadliest substances known.

Genetic engineering is not the only way to reduce allergens in foods. Enzymes can be used to break down the proteins in the processing of the foods. In Japan , this method is already used to make some non-allergenic baby formulas and rice.

Another approach is to make people less allergic. Tanox, a biotechnology company in Houston , is testing a drug to decrease the severity of peanut allergies.

Source- Boston.com

10/11/02 

Two Pairs of Genes are Involved in Higher Rate of Heart Failure Among Black People.  

Scientists have discovered that two pairs of genes that rarely occur together in whites increase tenfold the risk for heart failure among black people who have the double genes.

The presence of the two pairs of genes plays 25% of the cases of congestive heart failure diagnosed each year among blacks. About 5 percent of U.S. blacks have both sets of genes.

According to the American Heart Association, about 4.8 million Americans have congestive heart failure. 3.5 percent of all black men, 3.1 percent of black women, 2.3 percent of white men and 1.5 percent of white women are affected.

One of the gene pairs increases production of a chemical that increases blood pressure, heart rate, and the heart's contraction and relaxation. The other gene pair makes heart cells which take up the chemical, norepinephrine, more sensitive to it.

The next step, according to the researchers, is to find what other genes are involved, and how they affect patients' response to various drugs.

Source- Associated Press

10/03//02 

Malaria and Mosquitoes Genomes Sequenced 

Researchers in ten countries sequenced the genetic code of both the malaria parasite, known as Plasmodium falciparum (the deadliest form of malaria) and Anopheles gambiae mosquito that bites humans and spreads malaria to millions.

An infected mosquito spreads malaria by injecting saliva containing malaria into a human bite. The parasite (at this stage is known as sporozoites) then flows into the blood stream to the liver and multiplies into dense cysts filled with parasites. The cysts burst and the parasites (known as merozoites) enter the red blood cells. Another mosquito picks up the parasite by biting an infected human. The parasite reproduces and its offspring migrate to the salivary gland of the mosquito where the cycle starts again.

Malaria is characterized by high fever, chills, and anemia from the destruction of the red blood cells. Almost 2.7 million people die annually of malaria, 90 percent of them in Africa and most of them children under the age of 5.

Decoding the genome of malaria and the mosquito will help scientists find new ways to combat the disease and develop better insecticides against the mosquito. Already scientists have identified gene weaknesses that may be exploited to disrupt the life cycle of the malaria parasite.

Source- Washington Post

9/27//02 

Milk from Cloned Cows Appear to be Normal

Recent studies are showing that the quality of milk from cloned cows is virtually indistinguishable from that of normal cows. The result of the studies will most likely speed up the development of commercial agricultural cloning in the United States .

The studies were conducted at the University of Wisconsin and the University of Utah .

Don Coover, a veterinarian and rancher from Galesburg , Kansas , said, "There's no great fear or apprehension about it, in farm country."

The FDA is drafting guidelines for producers who want to employ animal cloning.

Dozens of cloned cattle and pigs have been created already by American companies and returned to farmsteads. Each clone cost $20,000 or more to produce. Because they are so expensive, farmers are not interested in selling them as meat.  Rather, farmers and ranchers want to use the clones as breeding stock to improve the quality and output of entire herds. In addition, farmers will sell the clones' milk, and eventually, use first and second generation offspring as meat.

There is no law or regulation against sales of products from clones.

Consumer advocates had said that the American public remains very suspicious of animal cloning, mainly on religious and ethical grounds.

The National Academy of Sciences and other organizations have expressed concern about breeding clones due to needless suffering of these animals. Most of them die in the womb or shortly after birth.

The scientific data on milk have been submitted for publication to a major journal. The results show that clones and normal cattle produce milk that is almost identical in protein, milk solids, fat and minerals.

Despite the new data, it is still possible that milk from clones differ from normal milk in subtle ways that might have an impact on human health. Most scientists consider it unlikely, but more studies to address this issue are in progress.

Source- BBC News 

9/25//02 

Behavior of Slime Mold As a Model for Human Cancer

Scientists at Dundee University in the United Kingdom are studying slime molds in leaf litter to better understand how cancer cells work. These molds are single cell organisms whose movement is similar to that of human cells within tissues.

The scientists discovered that genes which control mobility in human cells have similar functions in slime molds.

The Dundee team looked at a gene called APC, which when mutated, can cause bowel cancer in humans. The APC protein was shown to affect slime mold movement.

The role of APC protein in mold is helping the scientists understand how bowel cancer develops.

Dr Inke Nathke, the principal investigator in the study, said, "We've set up a new system to study this key cancer gene - one which in a few years is likely to produce a wealth of information about how the disease develops. In a relatively short space of time, our studies have provided some interesting information about the role of this gene in cancer and we think the organism will be useful for looking at a number of genes as well."

Sir Paul Nurse, chief executive of Cancer Research UK , said: "The discovery that we can use the slime mould as a model for some of the processes involved in human cancer is an important step forward and one that should help us to discover the function of the number of key cancer genes."

Source- Ananova

9/24//02 

Human and Chimps are Not so Close

Scientists at California Institute of Technology have found that human and chimps DNA were 95% identical. Biologists have always thought that the similarity was higher, about 98.5%.

Using a computer program comparing 780,000 base pairs, biologist Roy Britten demonstrated that humans and chimps differed by 5%. The scientist found more mismatches than was found earlier. 

According to the researcher, the next stop is to compare how the genes are regulated in the two species and locate the genetic differences within the DNA.

Source- BBC Online News

9/09//02 

Study of Sperm could help Infertility in Men

Scientists in the United States and Great Britain have mapped out a 3,000 base-pair sequence from a single sperm of a healthy, fertile man.

Comparison of the sequence, which was read from the messenger RNA (mRNA), to the sperm of infertile men, will help unravel the reasons behind infertility in men.

The technology used to map mRNA could also be used to screen sperm from the cells most likely to produce an embryo.

Source- BBC Online News

9/07//02 

The Genome of Rice

The recent completion of the genomes of two closely related types of rice will provide important information in helping scientists improve rice production and allow it to tolerate harsh conditions.

The researchers at the University of Indiana , US, say that unraveling the genome of rice is very important since it is the main staple diet for half of humanity.

Rice is also a model for all grasses and thus will provide a basis for future improvement of cereal grains.

Source- Yahoo Online News

9/03//02 

Scientists identify a Cleft Lip and Palate Gene

American and British scientists have discovered a mutant gene that causes the inherited form of cleft lip and palate (Van der Woude Syndrome) in Brazilian identical twins. Only one of the twins had the disorder.

The discovery will allow physicians to provide more accurate genetic counseling, but new therapies are still a long way away.

Cleft lip is one of the most common birth defects. It causes an opening between the mouth and nose or a gap in parts of the mouth. Surgery, orthodontic treatment and speech therapy are the only methods used, so far, to treat the defect.

Most cases of cleft lip and palate are due to a combination of genetics and environmental factors, but Dixon and his colleagues, the scientists involved in the discovery, believe Van der Woude syndrome is due to a single faulty gene.

By studying the faulty gene named Interferon Regulatory Factor 6 (IRF6) the scientists hope to eventually prevent the disorder.

 Source- BBC News

8/21//02 

Chocolate, Cola and Coffee May Fight Cancer 

British scientists have found that caffeine and theophylline may be effective in fighting cancer tumors. Both compounds are found in foods and drinks such as  coffee, tea, chocolate and Coca Cola.

The compounds target an enzyme called p110 delta, which plays a role in the survival and movement of tumor cells. In laboratory tests, the researchers at University College London showed that caffeine and theophylline both blocked a biochemical process crucial to the functioning of the enzyme. Dr. Peter Shepherd said the findings could pave the way for new treatments for cancer. The research is published in the Journal of Biological Chemistry.

Source- BBC.com

8/09//02 

Muscular Dystrophy Genes Discovered 

Scientists at the University of Massachusetts Medical Center in Worcester, US have found several genes involved in some form of Muscular Dystrophy.

The third most common form of the disease, known as Facioscapulohumeral muscular dystrophy (FSHD), mainly affects the face, shoulders and arms, but can progress to the lower limbs as well. 

The researchers studied a key region on chromosome 4- copies of the DNA sequence called D4Z4.

It seems that patients with FSHD have fewer than 11 copies of this sequence in their genetic makeup - compared to unaffected people with as many as 150.

This particular DNA sequence makes a protein that has the ability to suppress the activity of other genes. Therefore, less D4Z4 sequences are available to control the activity of these genes. A gene that may trigger cell death when active can lead to progressive decline of muscle cells.

According to the scientists, there may be other factors, such as other genes or environmental influences which could play a role.

The Massachusetts scientists believe it may be possible one day to develop a treatment that mimics the protein and suppresses the activity of the genes.

Source- Reuters.com

8/05//02 

The Mapping of the Mouse Genome

A group of scientists from Britain, Canada, and the United States have mapped 98 percent of the mouse genome, which is published on Nature online, the Web Site of the Nature science journal. Mice and humans have a similar number of genes, ~30,000. 

The mapping of the mouse genome will help facilitate the hunt for human genes that contribute to diseases. Mice have been used as models to study human diseases and to develop and test new treatments.  

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