World First: Chinese Scientists Create Pluripotent Stem Cells from Pigs

A scientist named Dr Xiao and colleagues have managed to induce cells from pigs to transform into pluripotent stem cells (cells that, like embryonic stem cells, are capable of developing into any type of cell in the body). It is the first time in the world that this has been achieved using somatic cells (cells that are not sperm or egg cells) from any animal with hooves (known as ungulates).

Dr Xiao succeeded in generating induced pluripotent stem cells by using transcription factors to reprogram cells taken from a pig's ear and bone marrow. After the combination of reprogramming factors had been introduced into the cells through a virus, the cells changed and developed in the laboratory into colonies of embryonic-like stem cells. Further tests confirmed that they were, in fact, stem cells capable of differentiating into the cell types that make up the three layers in an embryo – endoderm, mesoderm and ectoderm – a quality that all embryonic stem cells have. The information gained from successfully inducing pluripotent stem cells means that it will be much easier for researchers to go on to develop embryonic stem cells that originate from pig or other ungulate embryos. Dr Lei Xiao, who led the research, said: “it is entirely new, very important and has a number of applications for both human and animal health."

Pig pluripotent stem cells would be useful in a number of ways, such as precisely engineering transgenic animals for organ transplantation therapies. They could also be used to create models for human genetic diseases. However, Dr Xiao warned that it could take several years before some of the potential medical applications of his research could be used in the clinic.

Reference: http://www.sciencedaily.com/releases/2009/06/090602192557.htm

Why Can We Talk? 'Humanized' Mice Speak Volumes About Evolutionary Past

Mice found with a gene, similar to the human gene that is believed to influence speech, tho unable to speak show a huge link to humans evolutionary past. This is because human and mice’s genes are essentially the same and they work similarly. This study gives us a first glimpse that mice can be used to study not disease but also the history of human evolution. It is only in the last decade or so that scientist have discovered how similar mice and human genes are.

Wolfgang Enard of the Max-Planck Institute for Evolutionary Anthropology said that his team studies the genomic differences between humans and other primates. And important difference between humans and chimpanzees that has been studies by the team is two amino acids substitutions in FOXP2, these changes became fixed once human’s lineage had split for chimpanzees. Many changes in FOXP2 have occurred over the course of human evolution and this is the most likely candidate for the genetic changes that allow human speech. The study to determine this cannot be done on humans for obvious reasons. This lead researcher to introduce the substitutions into the mice’s FOXP2 gene, they identified that the mice’s gene is identical to that of chimpanzee’s so this is a reasonable model for ancestral human version.

Mice with the human FOXP2 show changes in brain circuits that have previously been linked to human speech. Intriguingly enough, the genetically altered mouse pups also have qualitative differences in ultrasonic vocalizations they use when placed outside the comfort of their mothers' nests. However Enard stated that not enough is known about mouse communication at this time to read to much into what this means. Although FoxP2 is active in many other tissues of the body, the altered version did not appear to have other effects on the mice, which appeared to be generally healthy.

The study of FOXP2 has shown that people with one nonfictional allele have show impairments in the timing and sequencing of orofacial movements, one possibility is that the amino acid substitutions in FOXP2 contributed to an increased fine-tuning of motor control necessary for articulation. Through the further studies of human mice and other primates the reason for speech will be discovered.

Original article: http://www.sciencedaily.com/releases/2009/05/090528120643.htm

Adam Gauger -42014016

Drug hope for advanced melanoma

Skin cancer, which is caused by excessive exposure to ultraviolet radiation, generally from the sun, is the most commonly diagnosed form of cancer. The most deadly form of this cancer, melanoma, claims many lives around the world every year. Currently melanoma is very difficult to treat when it is at an advanced stage, with less than 5% of those diagnosed with malignant melanoma which has spread around the body, live for more than two years. However UK scientists believe that they have discovered a drug that can treat the melanoma skin cancer in its most advanced incurable stages.

Two UK scientists, Roche and Plexxikon, have discovered that an experimental drug, PLX4032 (R7204) has the potential to help many patients with the incurable disease live longer and keep the disease in check. They presented their findings at a recent renowned US cancer meeting.

60% of malignant melanomas are implicated with a mutation called the BRAF mutation. The PLX4032 drug works by seeking out and destroying tumour cells which carry this mutation. This can help to not only shrink the size of the skin cancer, but also delay its spread. The early findings of their study involving 16 patients, with BRAF positive melanoma and treated with PLX4032, saw that over half of the patients saw the extent of their cancer reduce by at least 30%. These patients also lived for a median of six months without their disease getting worse. This included patients where the cancer had spread to the liver, lung and bone.

Current treatments for advanced melanoma, such as chemotherapy, can lead to an improvement in symptoms and quality of life but does not greatly extend life as this drug has the potential to do. The results are very exciting especially in areas such as Queensland which holds claim to the title “skin cancer capital of the world”, however there is still a long way to go. Dr Jodie Moffat of Cancer Research UK said: “While these results are interesting, they need to be followed up in much larger studies before we know if this is a new treatment for people with advanced melanoma.”

By Hannah Brodie - 41770436

Link :

http://news.bbc.co.uk/2/hi/health/8076743.stm

Possible cause of Alzheimer’s disease caused by hyperphosphorylation of tau proteins may have a genetic link.

A recent discovery by researchers at McGill University and Lady Davis Research Institute for Medical Research at Montreal's Jewish General Hospital promises to help in the diagnosis and curing of Alzheimer’s disease. They found that in patients will AD, there was a hyperphosphorylation (extra phosphate added) to one of the amino acids on a tau protein in the CNS. The 6 isoforms of Tau proteins are involved in the stabilisation of microtubules by their reaction with tubulin. When they are hyperphosphorylated, it causes a protein cascade with interaction between tau proteins resulting in neurofibrillary tangles that cause the neuron transport system to fail. This causes incorrect signals to be sent, and eventually neuron death. These tangles often occur in older individuals, but not on nearly as large a scale as in a patient with AD. A protein called beta-amyloid that builds up in neurons is also associated with AD, and thought to help cause cell death by interrupting cell homeostasis, causing apoptosis. By investigating the cause of this hyperphosphorylation, and build up of beta-amyloids, researchers hope to eventually find a cure for AD, as they believe that this hyperphosphorylation may be genetically linked. APOE is a gene that is present in 50% of late-onset Alzheimer’s disease cases. Genetic interpretation of this gene could help to find a cure, and genetic modification of this gene in embryos could also help to cure it.

This discovery is very important, as Alzheimer’s disease is a very prominent disease in society’s elderly, and can have disastrous effects, such as initially short-term memory loss, then as the disease progresses, resulting in greater cognitive degeneration, confusion, irritability, mood swings, language breakdown and long-term memory loss. This draws on many of the concepts covered in the course, such as protein interactions, protein cascades, genetic modification and interpretation.

Andrew Buchan - s4202068

http://www.genengnews.com/genCasts.aspx

http://www.ncbi.nlm.nih.gov/pubmed/11801334

Transgenic monkeys pass on glow in the dark gene to offspring

A team of Japanese scientists have genetically modified monkeys whose hair, skin and blood glow when exposed to UV light and who have passed on this gene to their offspring, making them the first transgenic animals to do so.

The discovery was made by a team of scientists led by Erika Sasaki from the Central Institute of Experimental Animals and Professor Hideyuki Okano of the Keio University School of Medicine.

The team used viral DNA to integrate a fluorescent jellyfish gene for green fluorescent protein (GFP) into the common marmoset causing them to glow green. The researchers hope that the transgenic marmosets can one day be breed to study infectious human diseases, immunology and neurological diseases such as Parkinson’s disease.

Dr Kathie Raphael, a lecturer in Genetics at the University of Sydney explains how it could work saying, “If you want to study motor-neurone disease or Parkinson's disease, and you have a candidate gene that you believe causes the disease, then you introduce that gene into the monkey and…observe the effect that it has… if it causes the types of symptoms that it does in humans… then you've got a model to study the disease and try treatments."

link:

http://livenews.com.au/rss-link/breakthrough-as-glowing-monkeys-have-glowinthedark-babies/2009/5/28/208010


original research published in science journal Nature




posted by 41730766

December 11, 2006

How much of human height is genetic and how much is due to nutrition?

Molecular biologist Chao-Qiang Lai of the Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University answers.

This question can be rephrased as: "How much variation (difference between individuals) in height is attributable to genetic effects and how much to nutritional effects?" The short answer to this question is that about 60 to 80 percent of the difference in height between individuals is determined by genetic factors, whereas 20 to 40 percent can be attributed to environmental effects, mainly nutrition. This answer is based on estimates of the "heritability" of human height: the proportion of the total variation in height due to genetic factors.

Human height is a quantitative, or metric, trait, i.e., a characteristic that is measured in quantity, and is controlled by multiple genes and environmental factors. Many studies have estimated the heritability of human height. Often, these studies determine heritability by estimating the degree of resemblance between relatives. One can separate genetic effect from environmental effects by correlating genetic similarity between relatives (twin, siblings, parents and offspring) with their similarity in height. To accurately measure how genetically similar relatives are, one can measure the number of genetic markers they share. For example, Peter M. Visscher of the Queensland Institute of Medical Research in Australia recently reported that the heritability of height is 80 percent, based on 3,375 pairs of Australian twins and siblings. This estimate is considered to be unbiased, as it was based on a large population of twins and siblings and a broad survey of genetic markers. In the U.S., the heritability of height was estimated as 80 percent for white men. These estimates are well supported by another study of 8,798 pairs of Finnish twins, in which the heritability was 78 percent for men and 75 percent for women. Other studies have shown height heritability among whites to be even higher than 80 percent.

Because different ethnic populations have different genetic backgrounds and live in different environments, however, height heritability can vary from one population to another, and even from men to women. In Asian populations, the heritability of height is much lower than 80 percent. For example, in 2004 Miao-Xin Li of human Normal University in China and his colleagues estimated a height heritability of 65 percent, based on a Chinese population of 385 families. In African populations, height heritability is also lower: 65 percent for the population of western Africa, according to a 1978 study by D. F. Roberts, then at Newcastle University in England, and colleagues. Such diversities in heritability are mainly due to the different genetic background of ethnic groups and the distinct environments (climates, dietary habits and lifestyle) they experience.

Heritability allows us to examine how genetics directly impact an individual's height. For example, a population of white men has a heritability of 80 percent and an average height of 178 centimeters (roughly five feet, 10 inches). If we meet a white man in the street who is 183 cm (six feet) tall, the heritability tells us what fraction of his extra height is caused by genetic variants and what fraction is due to his environment (dietary habit and lifestyle). The man is five centimeters taller than the average. Thus, 80 percent of the extra five centimeters, or four centimeters, is due to genetic variants, whereas one centimeter is due to environmental effects, such as nutrition.

Heritability can also be used to predict an individual's height if the parents' heights are known. For example, say a man 175 cm tall marries a woman 165 cm tall, and both are from a Chinese population with a population mean of 170 cm for men and 160 cm for women. We can predict the height of their children, assuming the heritability is 65 percent for men and 60 percent for women in this population. For a son, the expected height difference from the population mean is: 0.65 x [(175 - 170) + (165 - 160)] / 2, which equals 3.25 cm; for a daughter, the difference is 0.6 x [(175 - 170) + (165 - 160)] / 2, which equals 3 cm. Thus, the expected height of a son is 170 + 3.2, or 173.2 cm, and of a daughter 160 + 3, or 163 cm. On the other hand, environmental effects can add 1.75 cm to a son's height: 0.35 x [(175 - 170) + (165 - 160)] / 2, and 2 cm to a daughter's: 0.4 x [(175 - 170) + (165 - 160)] / 2. Of course, these predictions only reflect the mean expected height for each of the two siblings (brothers and sisters); the actual observed height may be different.

Discovery of new gene gives hope to ALS sufferers

A recent discovery by a consortium of researchers, has given hope to individuals with amyotrophic lateral sclerosis (ALS), aka Lou Gehrig's disease. Headed by professors at the University of Massachusetts’ Medical School, the breakthrough relates to the discovery of the KIFAP3 gene variant, which substantially improves survival of individuals with the disease.

Reported in the Proceedings of the National Academy of Sciences the discovery of the KIFAP3 gene is an important and vital step in the understanding and possible future treatment of the disease. The Gene itself has been identified by the researches as being a genetic factor that determines the rate of progression in individuals with ALS; it represents the first of the only four known genes associated with causing familial ALS that has been linked to this rate of progression.

The discovery and isolation of the KIFAP3 gene was as a result of an international collaboration between more than 20 research teams from the U.S., Mexico, Israel and Europe that studied around 1800 people with ALS and 2200 unaffected controls. The researchers were looking for a naturally occurring gene variation that would influence a person’s susceptibility and the way that the disease manifested itself over time. This led the researches to the KIFAP3 gene, which was found to increase a person’s survival time by 40 – 50%. Due to the only recent discovery of this gene, researchers have yet to isolate specifically the way in which the gene variant affects the progression of ALS, however they know that its in involved with many cellular processes most specifically the transport of molecules within the nerve cells.

The hope in this discovery is that with further study not only can this gene lead to a better understanding of the progression of the condition itself but that it will also allow development of new treatments to combat the disease. Whereby treatments can be tailored to target and exploit the benefits of this gene variant. Especially as the collaboration showed that the variant by itself was comparable in effectiveness to the only available drug in the US, Riluzole.

ALS is a ‘progressive, neurodegenerative disorder affecting the motor neurons in the central nervous system. As motor neurons die, the brain's ability to send signals to the body's muscles is compromised. This leads to loss of voluntary muscle movement, paralysis and eventually death from respiratory failure’ it has no definitive cause and no cure - http://www.medicalnewstoday.com/articles/149766.php


References –

- http://www.medicalnewstoday.com/articles/149766.php
- Proceedings of the National Academy of Sciences