Clipmarks | pokkets's 'gene' clips

Gene Editing Could Make Anyone Immune to AIDS

Tue, 01 Jul 2008 16:31:20 GMT

clipped by: wildcat

Some people have a mutation that makes them amazingly resistant to HIV -- and now, scientists may have found a way to give that immunity to anyone.

Viruses enter cells and take them over, but to get inside, they need a handhold. HIV pulls itself in by grabbing onto a protein called CCR5, which decorates the surface of T-cells, which are one of the two major types of white blood cells and play an important role in helping the body fight infections. Back in the 1990's, researchers took interest in a handful of promiscuous gay men who were able to engage in sexual relations with their HIV-positive partners with impunity. Most of them had a mutation that kept their cells from producing normal CCR5 protein.

Armed with that knowledge, scientists have developed several tactics to block the production of CCR5 or perturb its shape so that the HIV virus can't grab onto it during the first step of its hijacking attempt

Tags: dna, hiv, immunity, viruses

Zebra's Stripes, Butterfly's Wings: How Do Biological Patterns Emerge?

Sun, 22 Jun 2008 17:08:30 GMT

clipped by: Silkweaver
clipper's remarks: Previous work identified a specific signal necessary for getting these fly egg cells to move; the problem is that this signal is “graded.” Like drops of ink spreading out on wet paper, this signal travels in between surrounding cells, gradually fading away as it moves outwards. But clear lines are required for pattern formation — there is no grey area between a zebra’s black and white stripes, between heart and liver cells and, in this case, between migrating cells and those that stay put.

How are graded signals converted to a clear move or stay signal? By examining flies containing mutations in different genes, the researchers discovered that one gene in particular, called apontic, is important for converting a graded signal.

Clip Source: www.sciencedaily.com

A zebra’s stripes, a seashell’s spirals, a butterfly’s wings: these are all examples of patterns in nature.

The formation of patterns is a puzzle for mathematicians and biologists alike.

How does the delicate design of a butterfly’s wings come from a single fertilized egg?

How does pattern emerge out of no pattern?

“Pattern formation is a classic problem in embryology,” says Denise Montell, Ph.D., a professor of biological chemistry at Hopkins. “At some point, cells in an embryo must separate into those that will become heart cells, liver cells, blood cells and so on. Although this has been studied for years, there is still a lot we don’t understand.”

As an example of pattern formation, the researchers studied the process of how about six cells in the fruit fly distinguish themselves from neighboring cells and move from one location in the ovary to another during egg development.

Tags: biology, development, embryology, biological patterns

In the Art of a DNA Graph, the Colors of Uniqueness

Tue, 17 Jun 2008 06:37:07 GMT

clipped by: einbar

Clip Source: www.nytimes.com

In the Art of a DNA Graph, the Colors of Uniqueness

Being biologists and doctors, red is our blood, red is our fluid

All people have in common more than 99 percent of our gene sequences. Yet the type of sequence variation portrayed here, caused by a single altered nucleotide, accounts for most of the genetic differences among humans.

The colors show the DNA type inherited from a father, mother or both parents. Red signals a “genetic mosaic” of the parents, with different sequence variants from each. Black and white rectangles show that a person inherited the same sequence variant from both parents.

“We wanted to synthesize variability into a clear pattern,” said Dr. Ruaño, who is president of Genomas Inc., which is developing genomics-based tools for diagnosis and drug prescription. “The eye is the most important pattern recognition instrument that humans have.”

Spink gene reveals prostate cancer

Tue, 10 Jun 2008 15:45:42 GMT

clipped by: pokkets

Clip Source: www.abc.net.au

Researchers believe they have found a compound produced by aggressive prostate tumours that could be used to develop a new urine test.

Scott Tomlins and colleagues at the University of Michigan Health System, published their finding in the journal Cancer Cell.

The finding could also help doctors know which patients need the most careful monitoring after surgery or radiation therapy to destroy the tumour.

The researchers looked at 1800 different prostate tumours to try to identify the unique signature of an aggressive type of prostate cancer, which is found in about 10% of cases.

They found that a gene called serine peptidase inhibitor, Kazal type 1 (SPINK1) was over-expressed, or overactive, in about 44% of cases of prostate cancer.

Tumours come back after surgery in somewhere between 25% and 40% of men, they said.

The presence of SPINK1 in urine could lead to the development of a urine test to detect prostate tumours.

Queen bees took time to play the field

Fri, 30 May 2008 03:01:01 GMT

clipped by: pokkets
clipper's remarks: They suggest that while worker bees are sterile, and cannot breed themselves, helping the queen allows their genes to be passed on, while at the queen having multiple partners can widen the gene pool.

Clip Source: www.abc.net.au

Anna Salleh

Queen bees only became polygamous once they were confident - evolutionarily speaking - that their offspring would be taken care of by the hive, say UK and Australian researchers.

Polygamous honey bee queens, like the one shown in the middle here, are a relatively recent evolutionary development

Behavioural ecologist Associate Professor Madeleine Beekman of the University of Sydney and colleagues report their findings today's issue of the journal Science.

The researchers compared the mating behaviour of 267 species of bees, wasps and ants that live together in highly co-operative societies.

They found that in older species, females were always monogamous and that species with polygamous females, such queen honey bees, evolved relatively recently.

The findings add weight to one explanation for a long-standing evolutionary paradox - why do some individuals of a species altruistically look after someone else's offspring?

Extinct thylacine genome brought to life

Tue, 20 May 2008 01:47:37 GMT

clipped by: pokkets
clipper's remarks: Known as the Tasmanian Tiger, it was one of the few marsupial predators that were in Australia before the arrival of the west. The other is the Tasmanian Devil, which survives, but is threatened by a disease that causes ulcers.

Clip Source: www.abc.net.au

Stephen Pincock

A genetic fragment of Australia's extinct Tasmanian tiger has been brought back to life by Melbourne researchers.

From extinction to gene expression ... a mouse foetus expressing the thylacine gene, shown by the blue staining

Dr Andrew Pask and Professor Marilyn Renfree from the University of Melbourne have inserted part of a gene involved in bone growth from the fabled animal into mice, and confirmed that it functioned.

"We've brought a fraction of this extinct genome back to life," Pask, at the Department of Zoology, says. "No one has done this in a living organism before."

The Tasmanian tiger or thylacine (Thylacinus cynocephalus) was a large, meat-eating native Australian marsupial that was hunted to extinction in the wild in the early 1900s.

Last of the Tasmanian tigers at the Hobart Zoo

The last-known animal died in captivity in the Hobart Zoo in 1936.

The latest breakthrough

published this week in the journal PLoS One, is the culmination of nine years of effort

Gene therapy helps blind see the light

Mon, 28 Apr 2008 09:59:45 GMT

clipped by: pokkets

Clip Source: www.abc.net.au

Deena Beasley and Ben Hirschler

Gene therapy for a rare type of inherited blindness has improved the vision of four patients, boosting hopes for the troubled field of gene repair technology, scientists say.

Gene therapy in preliminary, short-term trials has improved the vision of a handful of people with a rare but serious form of blindness. But much work is needed before this approach becomes routine

Two separate teams of doctors report successes in using gene therapy to treat Leber's congenital amaurosis, or LCA.

LCA damages light receptors in the retina. It usually begins affecting sight in early childhood and causes total blindness by the age of 30. There is no treatment.

Both teams used a common cold virus to deliver a normal version of one damaged gene that causes the disease, called RPE65, directly into patients' eyes.

"This result is important for the entire field of gene therapy," says High, a former president of the American Society of Gene Therapy.

Schizophrenia could involve 100s of genes

Sat, 29 Mar 2008 00:04:01 GMT

clipped by: pokkets

Clip Source: www.abc.net.au

Schizophrenia may be caused by many different mutations in many different genes that disrupt biological pathways vital to normal brain development, say researchers

The genetic fingerprint of each individual with schizophrenia is unique, say researchers

Two teams of researchers publish new genetic insights into the condition in today's issue of the journal Science.

Schizophrenia is a complex disorder marked by delusions, hallucinations and disordered thinking and appears in about 1% of adults.

Experts have long struggled to grasp its causes and the role of genetics and environmental factors.

Prior to the publication of this study, it was assumed that genetic studies like this one would trace the origins of the illness back to a cluster of common, or high frequency, genetic mutations.

The researchers found gene-disrupting DNA deletions and duplications are far more common in people with schizophrenia.

The duplicated or deleted strands of DNA differ from person to person,

Old donated blood a risk after surgery.

Thu, 20 Mar 2008 17:30:26 GMT

clipped by: pokkets
clipper's remarks: Blood has an official 'shelf life' of 6 weeks. The tendency to use old blood first to rotate stocks would mean that much of the blood used would be over the two week limit said to be dangerous.
Blood can't be frozen or the red blood cells burst. Huge volumes are used in transplant and heart surgery that have been much more common over the last few years. Much of the blood used in these cases ends up on the floor. If a blood bank supply reaches the two week limit, supplies are said to be critically low. There needs to be a redevelopment of the practice of blood supply and distribution, Perhaps with alternatives to whole blood and the types surgery being considered. 'Keyhole' heart surgery is one option that has that saves the need for huge transfusions, and patient stress.
Something I considerd as a comparison. How long can pasteurized, homogenized milk be kept in the fridge before it goes sour ?

Clip Source: www.abc.net.au

Gene Emery

People who get old, stale blood during surgery are 30% more likely to die from complications afterwards than people who get fresh blood, a US study suggests.

The study reported today in the New England Journal of Medicine found blood older than two weeks seemed to be associated with more complications after heart surgery.

"We report that the relative risk of postoperative death is increased by 30% in patients given blood that has been stored for more than two weeks," the researchers say.

This can cause a dilemma, as many blood banks and hospitals cannot keep enough blood on hand that is so fresh.

The US Food and Drug Administration allows blood to be held for as long as six weeks, and blood banks typically give out the oldest blood first.

One solution may be to use the freshest blood first.

However, a system that uses blood no older than two weeks would make it harder to keep blood banks properly stocked, and much more blood would be discarded.

Overeating disrupts web of genes.

Mon, 17 Mar 2008 07:33:05 GMT

clipped by: pokkets
clipper's remarks: They say perhaps they can develop drugs that will solve the problem.? Perhaps sensible eating would be a good idea. We don't have any idea of the effects of a bad diet on our genes, amongst many other things. Many of these effects are no doubt passed down to the children.

Clip Source: www.abc.net.au

Maggie Fox

Overeating disrupts entire networks of genes in the body, causing not only obesity, but diabetes and heart disease, in ways that may be possible to predict, researchers report.

The researchers developed a new method of analysing DNA and used it to discover that obesity is not only complex, something already known, but complex in ways that had not been previously understood.

"Obesity is not a disease that is the result of a single change to a single gene. It changes entire networks," says Dr Eric Schadt, executive director of genetics at Merck Research Laboratories.

His team identified networks of hundreds of genes that appear to be thrown out of kilter when mice are fed a high-fat diet.

"This network is completely rocked by exposure to a high-fat, Western-type diet," Schadt says.

This showed that people who have a higher body mass index, a measurement of obesity, have characteristic patterns of gene activation in their fatty tissues not seen in DNA taken from blood.

Royal jelly triggers queen genes

Fri, 14 Mar 2008 12:40:49 GMT

clipped by: pokkets
clipper's remarks: I'm sure any beekeeper can tell you that a queen bee is just a worker that has been fed royal jelly, They wanted to study the process in more detail, because the principle is thought to work in other animals, including humans, and they were also trying to work out how to make 'clean' queens in an attempt to help repair the damage to the honey industry with what has become affected by something known as Colony Collapse disorder. They achieved the same results as royal jelly when they switched of a gene Dnmt3, which showed demetylization of DNA led to the development of certain traits.
Studies continue, but in humans things like obesity,infertility, longevity, and brain disorders, are thought to be affected by the chemical effects on genes

Clip Source: www.abc.net.au

Anna Salleh

Royal jelly determines which bee larvae turn into queens by boosting the activity of particular genes, say Australian researchers.

In a colony of 60,000 bees, only the queen (marked in blue) can produce offspring. Now scientists say they know what sends larvae on the path to queendom

Molecular biologist Dr Ryszard Maleszka and colleagues from the Australian National University in Canberra report their findings today in the journal Science.

"The larvae that develop into workers and queens are genetically identical," says Maleszka.

Yet he says those fattened up on royal jelly become fertile queen bees and are much larger and longer-lived than the rest that turn into sterile workers.

Epigenetics involves chemical modification of the genome to change gene expression, and provides a way for the environment to affect an organism's genetics.

Some scientists think epigenetic factors explain why psychiatric diseases such as schizophrenia don't always appear in both identical twins.

Head lice came with us out of Africa

Thu, 07 Feb 2008 04:49:45 GMT

clipped by: pokkets

Clip Source: www.abc.net.au

Maggie Fox

Head lice taken from 1000-year-old mummies in Peru support the idea that the little creatures accompanied humans on their first migration out of Africa 100,000 years ago, researchers report.

Genetic tests show the lice are nearly identical to strains found around the world that have been dated to when humans first began to colonise the rest of the world.

"It tells us that this genetic type got around the globe right as humans spread and migrated around the globe," says Dr David Reed of the University of Florida,

"We know that this parasite was distributed all over the globe along with us."

Writing online in the Journal of Infectious Diseases, the researchers note there are three known strains, or clades, of head lice: A, B and C.

Reed believes he can use gene sequencing of lice to track and date human migrations all over the world.

The bloodsucking creatures can only live on humans. They die very quickly away from their hosts and cannot survive on any other animals.

Tiny gene differences make us who we are

Mon, 04 Feb 2008 08:44:37 GMT

clipped by: pokkets
clipper's remarks: It's not what they do, it's the way that they do it.

Clip Source: www.abc.net.au

Scientists have found more than 500 genes that account for variations across human populations including skin colour, height and vulnerability to disease, according to a new study.

By comparing millions of fragments of genetic code from individuals in four groups - from Nigeria, China, Japan and northwest Europe - researchers say that natural selection has played a key role in these differences.

The findings, which are published online ahead of print in the journal Nature Genetics, hold particular promise for understanding the genetic underpinning of certain diseases.

The researchers, led by Dr Lluis Quintana-Murci of France's National Centre for Scientific Research pinpoints, for example, the tiny genetic variation in the CR1 gene that has made 85% of Africans highly resistant to malaria.

Once the specific bit of genetic code responsible for a predisposition to a certain illness or condition has been identified, scientists can then set about trying to find a drug to treat it.

Gene map for synthetic life created in lab

Fri, 25 Jan 2008 01:56:47 GMT

clipped by: pokkets
clipper's remarks: The Bacterium, M. genitalium has the smallest known genome of any truly living organism, with 485 working genes all in one chromosome. Viruses are smaller, but they cannot replicate by themselves.
Dr Craig Ventner is described as a celebrity scientist.
Struck me as an unusual way to describe a scientist.

Clip Source: www.abc.net.au

Researchers have assembled the entire genome of a living organism - a bacteria - in what they hope is an important step to creating artificial life.

Their work is reported in today's issue of the journal Science

"We consider this the second in significant steps of a three-step process in our attempts to make the first synthetic organism," says the controversial celebrity US scientist Dr Craig Venter

The bacteria Mycoplasma genitalium has the smallest known genome of any truly living organism, with 485 working genes. Viruses are smaller, but they are not considered completely alive as they cannot replicate by themselves.

Bacteria can and do

J. Craig Venter Institute in Maryland has been working for years to try to build M. genitalium from scratch.

M. genitalium has a fairly simple structure - all its DNA is carried on a single chromosome.

Venter's team began by chemically making DNA fragments in the lab.

"This entire process started with four bottles of chemicals," he says.

Junk DNA tells tales of the pacific

Thu, 24 Jan 2008 09:04:23 GMT

clipped by: pokkets
clipper's remarks: The 800 genetic markers studied, described as 'Junk DNA' are also known as 'microsatelites'
and can vary a great deal between individuals, and can tell a great deal about a persons identity and history, according to the number of repeated segments.
I'm sure they'll find a better name for junk when they discover how it fits into the gene sequence. I have trouble imagining it is there without having a function, or even an effect, but we still have a lot more to learn about DNA than we'd like to admit. Still, it could be like saying there is a reason for fingerprints besides identification. (Maybe grip?)

Clip Source: www.abc.net.au

Jennifer Viegas

Polynesians and Micronesians bear little genetic relationship to Melanesians, say researchers who have been analysing junk DNA in the genomes of Pacific Islanders.

A new study, published in the current PLoS Genetics, finds Melanesians are among the most genetically diverse people on the planet and indicates how the Pacific was initially settled

The first people to enter the Pacific came from Southeast Asia, along the stepping-stone island chain - now Indonesia - to ancient Australia and New Guinea, and to the nearby islands just to the east and southeast, the Bismarcks and the Solomons,

They got there between 50,000 and 30,000 years ago, when Neanderthals were still roaming Europe

very, very early in modern human prehistory,

Melanesia was also settled around this time, probably by individuals from East Asia

Friedlaender and his

team looked at 800 genetic markers

Also called "junk DNA

Even when living on the same land, Polynesians and Melanesians appear to have kept to themselves