Thursday, September 29, 2011

"In-Vitro Fertilization Linked to Rare Genetic Disorders"

Dr. Rosanna Weksberg, a geneticist at the University of Toronto has been studying the correlation between in-vitro fertilized children and genetic disorders, particularly concerning mental disability and cognitive function. Her studies shown that in-vitro fertilization increases a child's risk of being mentally disabled by ten times and puts the child at a higher risk of two rare diseases: Beckwith-Wiedemann syndrome and Angelman syndrome. The first produces symptoms such as unevenly sized limbs and high risk of kidney tumors, while the second causes mental retardation and speech impairment. Both of these diseases are typically not inherited, but rather caused by a mutation in chromosomes 11 and 15 respectively.

Additionally, in-vitro fertilization is often linked to multiple births- twins, triplets, and beyond. The high proportion of these births are worrisome because of the high risks associated with multiple births, such as the need for intensive care unit and dangers to the mother.

The cause of these in-vitro induced genetic diseases are currently unclear. Predictions range from the biological parents infertility problems to In-Vitro treatment itself. However, research is being done to determine the causes using Preimplantation Genetic Diagnosis (PGD), a technology that studies the genes of in-vitro embryos before the embryos are implanted into the mother's uterus.

How should the government deal with the risks involved with In-Vitro Fertilization? Is this topic even in the domain of public affairs? Recently, Canada's Federal Assisted Human Reproduction Act was overruled, meaning that less public investment is going in research behind this procedure. But Quebec presents itself as a model of a successful In-Vitro policy, funding the procedure in 2010 under Medicare and all but eliminating unintended In-Vitro multiple births.

The debate around In-Vitro fertilization is truly interesting. By bringing the miracle of life to those who otherwise would not be able to, are we benefiting society by possibly increasing the risk of certain, harmful genetic mutations, decreasing the rate of adoption, or are we truly benefiting human population?

Here is the link to the main article:

And if you want to find out more about the studies behind In-Vitro Fertilization, here are a few sources:


There may be a naturally occurring fountain of youth at large in nature today. But how are we to know whether it’s the real deal when scientists cannot agree on its efficacy or application?

A New York Times article from last week states in its headline: “Longevity Gene Debate Opens Trans-Atlantic Rift.” Indeed, scholars from Michigan to London have been arguing for the last decade about the effects of resveratrol, a substance found in small quantities in wine and believed by some to extend the human lifespan.

In the recent past, hopeful American researchers have been countered by skeptics from across the pond who claim that the “longevity gene” does not exist. These Brits believe that, though recent studies have shown a 40% increase in longevity of rats due to a low-calorie diet and stimulated “longevity gene,” these studies may have been an ill-conceived sham. That longevity gene, which produces sirtuins (proteins which control cell metabolism and naturally occur in resveratrol—which naturally occurs in the skin of grapes), has been the object of scientists’ desires as of late. Sirtuins are proteins which control crucial cell functions like transcription, metabolism, and apoptosis. How can we stimulate the genes which produce these proteins to extend lives?

One answer: red wine! Because the average merlot contains trace amounts of reveratrol, it is now believed that drinking one glass of wine per day can prolong lives.

However, inspired by this discovery, scientists in the US and Europe are pursuing a pharmaceutical answer to red wine. Despite questions as to whether or not reveratrol truly boosts longevity, pharmabusiness giant GlaxoSmithKline dropped over $700 million to develop a resveratrol-feigning drug called Sirtris in 2008.

Questions remain as to whether or not sirtuin is efficacious without the extremely low-calorie diet, something untenable for most modern humans. And researchers from the University College of London have entirely refuted trials supposedly proving sirtuin efficacy in Drosophila.

As the two UCL scientists recently wrote, “The biology of againg is a young field with emerging pitfalls.” But there is still great hope in scientific communities that sirtuins and resveratrol may be two possible contenders in an ongoing search for a biological or pharmaceutical “fountain of youth.”

Longevity Gene Debate Opens Trans-Atlantic RiftBy NICHOLAS WADE
Published: September 21, 2011

Wednesday, September 28, 2011

Transposons Created the Modern Mammalian Pregnancy

We take for granted today that the standard pregnancy takes place entirely within the womb and typically lasts about 9 months. This makes evolutionary sense; we can carry our vulnerable young in the safety of the womb rather than having to leave it exposed in a nest or a pouch. But this is actually a phenomenon unique to mammals, and is the result, not of small genetic mutations that impacted mammals over time, but of a rapid genetic rewiring that took place over 100 million years ago. A study conducted here at Yale that was published on September 25th, 2011, shows that the evolution of pregnancy in mammals owes much to transposons, otherwise known as “Junk DNA.”

The Yale professors examined uterine cells that are usually associated with placental development in opossums, armadillos and humans. Opossums are marsupials that give birth a mere two weeks after conception, while armadillos and humans, both mammals, have 9-month pregnancies and highly evolved placentas. The results of these comparisons showed that there were 1500 uterine genes that were unique to the placental mammals. This proves that these differences in uterine structure and pregnancy terms have their root in genetics.

About 13 % of the genes that were found in the placental mammals were very near on the genome to a particular kind of transposon. Transposons are pieces of genetic material that replicate within the host genome and used to be called Junk DNA because no one really understood their purpose. In a sense, transposons are parasitical because they multiply in the genome and affect it in a way that makes it carry out entirely new functions. These transposons in particular activated genes related to pregnancy and thus altered maternal-fetal communication. The transposons made the uterine cells more sensitive to progesterone, a birth-related hormone, and encouraged the cells’ development into the placenta. This resulted in a longer pregnancy term for mammals.

Ultimately, the take-away from this study is the fact that this was not a long-term process, it was a large-scale morphological change done relatively swiftly through a cut-and-paste operation that affected massive areas of the genome.

"Invasion of Genomic Parasites Triggered Modern Mammalian Pregnancy, Study Finds." Science Daily. 25 Sept. 2011. Web. 27 Sept. 2011. .

Lynch, Vincent J. "Transposon-mediated Rewiring of Gene Regulatory Networks Contributed to the Evolution of Pregnancy in Mammals." Nature. 25 Sept. 2011. Web. 27 Sept. 2011. .

"Junk DNA Gave Us the Modern Uterus, in a Giant Genetic Cut-and-Paste Operation." Discover Magazine. 27 Sept. 2011. Web. 27 Sept. 2011.

Monday, September 26, 2011

Australian Aborigine Hair Tells a Story of Human Migration


This story, published last week in the New York Times, reports the first genome test performed on a Aborigine Australian (the DNA actually came from a 100 year old piece of hair). Aboriginals are direct descendants of the settlers of Australia. Through the results of the test, scientists recognized the significance of the Aboriginal DNA. Because the DNA was not mixed with DNA from any other race, scientists concluded that the ancestors of Aboriginal Australians migrated directly from Africa, before the split of the Europeans and Asians, thus refuting the previously accepted migration theory. This migration theory stated that one out-of-Africa emigration wave occurred which colonized Europe and Asia, and then Australia, by a small group breaking off from the Asian group. With this new evidence, we see there were two waves of emigration from Africa. The first traveled through Asia and settled Australia. They were the first humans to leave Africa. The second occurred 24,000 years after and split into the Europeans and Asians. The second wave never traveled to Australia. This breakthrough discovery leads scientists to wonder if perhaps the colonization of the world occurred in even more waves.

I also found a lot of useful information from this article

Jumping Genes Capture Deep Relationships between Parrots and Songbirds

Earlier this year a study was conducted by scientist at Munster University to try and track the genetic history of the superior vocal abilities of certain bird species. Suprisingly, bird and humans share many higher cognitive functions (for example: color vision, superior vocal abilities, memory, etc.); therefore by studying the ancestry of the higher cognitive functions of birds, scientists might gather more information on similar functions possessed by humans. The study conducted was prompted by information collected during an experiment three years ago in which a group of scientists examined 32 kilobases of nuclear DNA sequences for 169 species of birds (representing all major extant avian groups) and found that the song birds (Passerines) closest relative was in fact, not other birds that were physically similar to it) but the parrot (Pstittacine). The new project was based off of the hypothesis that the similarities between pstittacine and passerine families could be explained by retroposons. The experiment tracked the presence or absence of two retroposed elements: chicken repeat 1 CR1 and LTRs of endogenous retroviruses. The results indicated that a avian family tree could be constructed based on the absence or presence of these retroposons. This new family tree showed a strong relationship between sriemas, falcons, pstittacines, and passerines.

A Mosaic Activating Mutation in AKT1 Associated with the Proteus Syndrome

The Proteus Syndrome was made known to the masses through the 1980's American film, The Elephant Man. The rare syndrome is characterized by an overgrowth of skin and tissues that create bulbous physical deformities. The New England Journal of Medicine recently published this article that associates a mutation in the AKT1 growth gene as a cause of the Proteus Syndrome. The experiment was conducted using exome sequencing and its results have allowed the world of genetics to further explore treatments for the life threatening syndrome.

Here is a link to the article in pdf format:

Thursday, September 22, 2011

Sequencing 'Dark Matter' of Life: Elusive Genomes of Thousands of Bacteria Species Can Now Be Decoded

In a recent published study, researchers at the University of California, San Diego along with scientists from the J. Craig Venter Institute and Illumina Inc. were able to create a new algorithm that greatly increased the ability of researches to sequence the DNA of bacteria from a single cell. This development allows scientists to sequence and analyze the genomes of thousands of species of bacteria that were previously inaccessible and impossible to study due to their environment-specific nature. Many of these bacteria only function in extreme conditions that are difficult to reproduce for a billion cells in a lab. Therefore, the ability to sequence the genome of a bacterium from one single cell is truly revolutionary. Scientists can now understand how bacteria move, live, and interact in a variety of settings. With the ubiquitous presence of bacteria in the human body, this occurrence also allows scientists to better comprehend how bacteria interact in different organs.

Wednesday, September 21, 2011

Glowing Kittens Fight Feline AIDS

The world is generally aware of the AIDS epidemic. While HIV is a commonly recognized infectious virus, there are actually two AIDS epidemics worldwide. One is human immunodeficiency virus (HIV); the other AIDS epidemic is feline immunodeficiency virus (FIV) found in your common housecat, of which there are 90 million in the United States alone. Known as lentiviruses, FIV and HIV produce similar symptoms but are non-transmittable between felines and humans. Why?

In 2007, scientists at the Laboratory of Genomic Diversity finished the Cat Genome Project. Using this data to the human genome, scientists in previous studies have hypothesized that the issue was the cat’s lack of the antiretroviral restriction factor protein TRIMCyp generated by the TRIM5 gene. Possessed by humans and monkeys, the gene codes for proteins that target the outer-shell of the FIV virus, marking it for degradation. Lacking this protein, felines are far more susceptible to FIV.

Would a feline with the TRIMCyp gene resist FIV? Molecular virologist Eric Poeschla hypothesized yes; however, the intentional insertion of new genetic material into an embryo is difficult. Somatic cell nuclear transfer -- replacing the egg nucleus with that of an adult with the new genetic material -- only has a 3% chance of success. Instead, Poeschla turned to a virus. For the first time using a carnivore subject, he and his team created a new lentivirus containing both the gene TRIMCyp, but also a green fluorescent protein (GFP) commonly found in jellyfish. Infected with the virus and fertilized by regular cat sperm, eggs were placed into the fallopian tubes of 22 cats. The result was three kittens. This embryonic version of gene modification, with 23% efficiency, was significantly better than the previous 3% efficient procedure.

Thanks to GFP, scientists did not have to run tests or examine the offspring’s DNA to determine whether the new genetic material had successfully transferred. Scientists only had to turn off the lights, shine a blue light, and look for the green, glowing cat. And back in the laboratory, FIV replicated poorly in the bloods cells of the genetically modified kittens.

Implications of this gene therapy experiment are still unclear. While the kittens are not cured or immune to FIV, the experiment ultimately demonstrates potential factors to the process of gene therapy. Obviously, the human genome most likely will not be altered to include the green fluorescent protein. Nor will we be able to buy green, glowing cats at PetCo. But, this form of embryonic gene therapy, with a higher efficiency rate than the previous proven method, suggests a potential for future human gene therapy. And if the HIV virus can be manipulated in manner similar to FIV, the benefits for humans are even more obvious.

Poeschla's Report:

View original article (09/11/11) from Science Magazine:

Image taken from source article.

Tuesday, September 20, 2011

An Immune System Trained to Kill Cancer

An Immune System Trained to Kill Cancer by Denise Grady from The New York Times September 12, 2011

The New York Times reported last week that scientists at the University of Pennsylvania might have discovered a new method of treating – or even curing – cancer. Dr. Carl June of UPenn’s Cancer Center tested a method of genetically engineering T-cells to specifically attack cancer cells in a patient with leukemia. Doctors removed about a billion T-cells – the white blood cells that fight infections – from the patient’s body by filtering his blood and then exposing the T-cells to an altered form of HIV-1. The HIV-1, a harmless variant that was altered to no longer cause AIDS, inserted a copy of a gene to produce chimeric antigen receptors (CARs) into the T-cells. HIV-1 is a retro-virus, which means that it carries enzymes which allow it to cut up parts of the genome and insert new DNA; in this case, the DNA it was inserting would strengthen rather than weaken the immune system. The CARs allowed the genetically modified T-cells to seek out the cancer cells and kill them. Once inside the body, these T-cells multiply and wipe out the cancer by destroying all B-cells – the blood cells affected by leukemia – that carry the CD19 protein on their surfaces. After the cancer is gone, memory cells are left behind to fight the cancer if it comes back. Once the B-cells have been destroyed, the patient is left essentially cancer-free.

So far, only three patients have undergone this treatment. Of the three, two went into complete remission, while the third went into partial remission. This treatment was only tested on patients with chronic lymphocytic leukemia and it is not clear if it would be work on other types of cancer. More tests will be needed to determine whether this treatment is truly as effective as it appears. At this point in time, no drug companies are testing genetic modification of T-cells to fight cancer and research is only in the beginning stages. There are certain risks that come with treatment: as the T-cells fight cancer, they cause high fever, low blood pressure, swelling and inflammation. In addition, the engineered T-cells can accidentally attack healthy tissues if the proteins on the tissues are too similar to the ones that the T-cells are supposed to kill, such as those cells that line the chest and abdomen. Treatment could also cause mimic lupus, an autoimmune disease. After treatment, memory cells remain behind to kill any future cancer cells, but they also attack normal B-cells, which leads to immunosuppression. Monthly intravenous immune globulin injections are required for protection from other illnesses. In spite of these risks, the genetic alteration of T-cells is an exciting new way of treating cancer that must be explored further to discover its true risks and benefits.

View the original article at:

Image comes from source article

You Look Familiar: Another piece of humanity's family tree is fitted into place

In 2008, scientists found the fossils of a new australopithecine species, Australopithecus sediba, in a cave in South Africa. Dr. Lee Berger of the University of the Witwatersand, in Johannesburg led the research. He first concluded that the species came too late in the fossil record to be an ancestor of the Homo lineage. However, further research into the specimen has revealed that sediba did predate Homo erectus. He also found that parts of its anatomy are similar to that of modern man.

X-rays of the interior of the skull showed that the size of the brain was consistent of that of other australopithecines, but the shape of the brain was more like that of a modern human brain. In particular, the frontal lobes, the site of higher cognitive function in humans appeared more humanlike in sediba's brain than in the brains of other australopithecines. Scientists previously thought that these kinds of neurological changes, which eventually gave rise to humanity, occurred after the expansion of the brain. However, these studies suggest that the changes predated this expansion. Additionally, studies of the fossils show that this australopithecine walked upright and had an upright, butterfly shaped pelvis, like that of a human. Scientists have long debated whether bipedalism or giving birth to babies with large heads drove the changes in the shape of the human pelvis. Sediba adults, and so likely their children, had small heads, suggesting that walking upright was the advantage attained first by the modern pelvis.

With these discoveries, Dr. Berger now posits that sediba may have evolved from an earlier Australopithecus species directly into Homo erectus. This would mean that Homo habilis, which was previously thought to be a transitional form between Australopithecus and erectus, was not an early human, but an evolutionary offshoot, and not a part of the genus Homo.

Monday, September 19, 2011

Splicing Our Way Towards Stem Cell Pluripotency

Stem cells carry medical utility because of their pluripotency— a mutability of functional destiny. Because they have the potential to become any kind of cell in the human body, they could theoretically be cultured to replace tissues ravaged by injury or illness, or to produce the media on which experimental drugs can be safely tested.

According to a team of Toronto-based molecular geneticists, this infinite potentiality is regulated via alternative splicing, by which a single gene can yield several different proteins by combining different exons in primary RNA. UToronto’s Benjamin Blencowe claims that the gene FOXP1 controls the synthesis of transcription factors— proteins that determine pluripotency— through alternative splicing. These proteins curtail the ability of a cell to specialize— to lock in its biological destiny as skin cell or gland cell, neuron or blood cell.

Blencowe’s team is hopeful that a better understanding of this alternative splicing process will allow scientists to make more sophisticated progress in learning how to “reprogram” cells— that is, reintroduce pluripotency to functionally static adult stem cells. As it stands, cells reprogrammed using existing knowledge have the tendency to be carcinogenic, making them therapeutically useless.


The Elusive HIV Cure

Reserachers at Sangamo, a biotechnology company that aims to “turn genes on and off” may have discovered a “functional cure” for HIV.

The study tested a new gene treatment on ten HIV positive patients, all of whom currently manage the infection through highly active antiretroviral therapy (HAART). Of the ten patients, six achieved positive enough results to temporarily cease taking HAART, leading to the virus’ decreased presence in four (to the extent where it was nearly undetectable in one).

Sangamo’s strategy is to target the CCR5 gene, which codes for a receptor that the HIV virus uses to enter the body’s immune system. The treatment, still in primary experimental stages, aims to shut off both alleles of the gene in as many cells as possible.

The treatment, known as SB-728-T, turns off the gene by distorting the genetic code for transcription factors, specifically zinc finger DNA-binding proteins (ZFPs). It also modifies the code for the gene itself through insertions, deletions, and mutations caused by zinc finger nucleases (ZFNs).

According to Dr. Carl June, the director of a research facility at the University of Pennsylvania, the treatment has the potential to render HAART obsolete. He noted the statistical relationship between an increased percentage of cells with the altered gene and the decreased impact of HIV – the patient whose HIV was nearly undetectable had double the number of altered cells by the end of the trial than the other patients.

With the planned expansion of Sangamo’s trials we may be seeing a functional cure for HIV/AIDS sooner than you thought.

Original article:

For more information on how HAART works:

For more information on the CCR5 gene:

Sunday, September 18, 2011

New Fossils May Redraw Human Ancestry

I found this article and thought it was really interesting to see how fossils found can create a completely different sketch of what the actual course of human development and evolution was like.

Wednesday, September 14, 2011

UCLA psychologists discover a gene's link to optimism, self-esteem

Life Scientists in UCLA have determined that the oxytocin receptor gene (OXTR) is linked to optimism, self-esteem and feelings of control over personal life. These psychological resources have been identified as vital mechanisms for being able to cope with stress and depression. The OXTR gene regulates the hormone oxytocin. This hormone increases as a response to stress and is therefore related to good social skills such as the ability to empathize and enjoy company.

OXTR has two versions. The first one is known as the "A" variant and the other as the "G" variant. According to their studies, people who have the "A" variant composed of either two adenine or one adenine and one guanine nucleotides at a specific sight of the OXTR gene, "have substantially lower levels of optimism, self-esteem and mastery and significantly higher levels of depressive symptoms than people with two guanine nucleotides.” The subjects were asked to take a test that determined levels of self-worth and optimism by evaluating statements such as “I feel I am a person of worth” and “I usually expect the best”. The subjects were also tested for depression with a test commonly utilized by psychologist to determine mental disorders. The results of the study were consistent with the variant difference.

Although Shelly E. Taylor, the senior author of the research, admits that having this gene does not guarantee the outcome, she insists that this identification is "highly significant" and has important implications". "Genes do not mean destiny," Shelly says, but there are many other factors that affect the expression of a gene. Furthermore, the gene was tested for interference with learning cooping skills and the results were negative. Therefore, people can train to become more optimistic and prevent depression through other social and psychological means. The effect of the knowledge these scientist have acquired is the ability to predetermine depressive tendencies in children so that social action may be taken to prevent the effects. The group is also continuing research for additional genes that may predict behavioral responses to stress and how they interact with OXTR.

Genetically Modified Crops

Genetically modified crops have been a continual source of debate over the past few years, but this topic is now more prevalent than ever.  As crops are at their height in price and yield is declining, the need for a more efficient way to produce food is much greater.  In addition, because the world's population is growing so quickly (possibly to an additional 3 billion people during this half of the century), genetically engineering crops is becoming a much more favorable option than it was in the past.

Although strides made have raised the productive value of land to 10 times what it was 100 years ago, there is much more that needs to be done.  This improvement in productivity is the result of plant mutations via chemicals and radiation, chemical disease and pest control, and agricultural mechanization. However, better technology now exists that will hopefully further increase food production.

Molecular additions and modifications to crop genes have proved an even more effective way to increase crop production.  These modifications can protect plants from pests and diseases as well as reduce the need for pesticide use which benefits the environment and farmers.  This approach is a more targeted and refined version of plant mutation from chemicals and radiation.

Overall, though there is still a debate over whether or not these genetic modifications are safe, many believe that implementing genetic modifications in crops is the only chance our world has to produce enough food for our growing population.  These people also call for government agencies like the EPA to reduce its regulations to promote innovation in this field.

Genetically Engineered Food For All

Tuesday, September 13, 2011

Scientist Discover Genetic Mutation that Causes Parkinson's Disease

Recently, scientists at the Mayo Clinic discovered another genetic mutation that causes Parkinson's disease. This is already the third gene that the Mayo Clinic has discovered with a strong link to the horrible illness.

We already knew that Parkinson's is caused by the death of dopamine containing cells in the substantia nigra, a region of the midbrain. This study farther expands on this knowledge. Scientists identified the gene EIF4GI that helps to produce proteins which a cell needs to cope with biological stress. When this gene malfunctions, cells are unable to cope with biological stress and as a result they die. This in turn causes the disease. This is a new discovery because none of the other genes connected to Parkinson's function in this way. The scientists are hoping that this discovery will lead them to new ways of preventing, curing or slowing the illness.

The discovery was made after studying a large French family with inherited Parkinson's disease. While conducting genetic tests, the scientists stumbled upon the mutated EIF4GI gene.

HSP60: How Do Our Proteins Fold?

Dr. Arthur Horwich, A medical geneticist here at Yale University just won an award for his work on and discovery of HSP60, a protein that acts as a "changing room" of sorts for other proteins. Newly formed proteins enter the HSP60 where they can fold themselves into their final functional shape.

As we know, proteins start out as a polypeptide. According to an experiment by the biochemist Christian Anfinsen in the 1950s, the amino acids' own attractions and repulsions were the sole force creating the protein's final shape. Contrarily, Dr. Horwich found that proteins could not always fold themselves correctly on their own. He discovered that though HSP60 does not "grab a protein and fold it like an origami master . . . it gives the protein the isolation it needs to fold itself" correctly.

This discovery could lead to cures for multiple diseases. One such illness, Alzheimer's, in which people "develop clumps of tangled proteins in their brains," has been projected by a group from Johns Hopkins University to affect one out of every eighty-five individuals worldwide by the year 2050.

Read more about Dr. Horwich and his work in the New York Times article "Horwich Wins Lasker Award . . ."

Learn more about the protein itself at PhosphoSitePlus.

View the Johns Hopkins study here.

View information and renderings of proteins at Protein Data Bank Japan.

Neanderthal Genome Project

From an article in The New Yorker titled "Sleeping With the Enemy":

Evolutionary geneticist Svante Pääbo and his team at the Max Planck Institute for Evolutionary Anthropology in Germany are in the midst of many projects that attempt to define what makes us Human, but are most notably working on sequencing the entire genome of the Neanderthal. So far they have determined that at some point humans interbred with Neanderthals and that all non-africans have 1-4% Neanderthal DNA replacing the "Out of Africa" theory of migration with what has been dubbed the "Leaky Replacement" hypothesis. In order to complete this daunting task the team uses high throughput sequencing that enables scientists to replicate tens of thousands of snippets of DNA at a time which are extracted from ancient bone fragments.
The article also focuses on Pääbo's career starting from when he was a PhD student studying viruses fantasizing about extracting DNA from mummies. A brief history of Neanderthal anthropology is featured in the story as well. With his research project, Pääbo is most interested in determining what genetic mutation resulted in the "craziness" that is only found in modern humans. To quote Pääbo, "it will be amazing to think that it was this little inversion on this chromosome that made all this happen and changed the whole eco-system of the planet and made us dominate everything. We are crazy in some way. What drives it? That would be really, really cool to know."

Monday, September 12, 2011

The Super Bug

The Super Bug has become a recent topic of discussion among doctors and medical experts in hospitals across the nation. Vancomycin-Resistant Enterococci (VRE) is an infection that is typically found in hospital patients, although it can occasionally occur in otherwise healthy individuals.

While the infection is typically not deadly, it causes thousands of patients to have extended hospital stays, which decreases patient flow, and drives up patient bills. The problem with VRE is that it is resistant to most antibiotics, with the sole exception being Daptomycin, which is a toxic substance that can cause as much harm to the patient as good.

Scientists are now looking at how VRE mutates when it is exposed to Daptomycin, hoping that they might learn how these gene mutations change cellular function within the VRE microbe.

Thursday, September 8, 2011

The Sleepy Gene and Our Circadian Rhythms

From an article in the Scientific American:"The Sleepy Gene"

Balanced circadian rhythms and proper sleep patterns are essential to overall health. Scientists at Northwestern University have isolated a gene in fruit flies which is linked to their sleeping patterns, strongly affecting their circadian rhythms. When they deleted the gene, the flies slept only during random intervals throughout the day and were less active overall. As humans and fruit flies are known to be genetically similar, with 61% of human disease genes having a match in fly genetic codes and 50% of fly protein sequences having mammalian analogues, it is likely that a similar gene will be found in humans.

If so, the Sleepy Gene will shed light on our circadian rhythms and may help us understand issues concerning our overall health, such as sleeping well and being able to wake up comfortably in the morning. 

Genomic scissors join the fight against genetic disorders

For the past 25 years, the field of gene therapy has all but remained in its experimental phase. But now, its unfortunately lethargic progress should experience a well-deserved boom. A team of scientists at the Children's Hospital of Philadelphia, led by Katherine High, have performed the first successful, in vivo genome editing procedure. Genome editing is a revolutionary gene therapy treatment that allows scientists to precisely target and repair a gene defect, effectively cutting out the mutated sequence and splicing in a healthy copy of the gene. Before genome editing, gene therapy techniques mostly consisted of randomly delivering replacement genes, sometimes to a wrong location, which could cause leukaemia and other cancers. This is the first time this treatment has been performed on live animals with clinically meaningful results.

High's team injected haemophiliac mice with enzymes called zinc finger nucleases (ZFNs). These enzymes were contained within artificial virus shells designed to "find their way to the liver, where blood clotting proteins are made." The ZFNs cut through the mutated gene (hence the 'genomic scissors' sobriquet), and delivered a DNA template of the healthy blood clotting gene in its place. This new gene was integrated, eliminating the mutation, and the mice's blood clotting times dramatically improved, a "a welcome breakthrough in a field that has struggled to deliver on the promise many scientists believe it holds."

High's team hopes to use a variation of this technique to "alter immune cells in HIV patients, which would make them resistant to the virus."

If you want to know more about how ZFN enzymes work, this easy-to-understand article has some very helpful diagrams. I have also embedded a YouTube video that nicely illustrates how ZFNs operate. The healthy gene integration procedure that High's team used in their experiments is shown around the 2:33 mark, although the entire video is worth a look.

Tuesday, September 6, 2011

"Twin studies are useless"

Interesting article on questions the validity of twin studies:

Traditionally measures of heredity for human traits came largely from twin studies: comparisons between identical twins (same environment, same genes) and fraternal twins (same environment, but no more related than any sibling pair).

But it's becoming increasingly clear that the assumptions of these studies are often invalid. Identical twins do not have identical genomes (they can differ in terms of the copy number of genes, for example), and the aspects of genome function are not static - they can change over a lifetime based on environmental factors. Moreover, environmental similarities are probably greater for identical twins: : "As anyone who's ever seen a pair of toddler twins in matching sailor suits is surely aware, monozygotic twins do get special treatment."

"The downside of sex with Neanderthals"

A paper in this week's Science (original research article HERE) compares the whole genome sequences of modern humans and Neanderthals (and Denisovans) to identify specific functional regions of the human genome likely gained through 'admixture' (i.e. sex) with Neanderthals. Interestingly, one of these regions represents a variant of an HLA (immune-related) gene that's associated with auto-immune disorders like Behcet's disease.

The Guardian has a nice summary of this research HERE.