Yeast owes its brewing capacity to chromosome duplication

Washington, May 15 (ANI): Yeast cells’ ability to convert sugar to alcohol, the key process in the production of beer and wine, can be attributed to a remarkable evolutionary process— called chromosome duplication.

The genes that allow yeast to digest sugars in fruits and grains have been duplicated several times over the course of time – allowing for optimal conversion of different types of sugars (such as sucrose and maltose) into alcohol.

The duplications arose because the genes for sugar processing are situated close to the unstable margin of the chromosome.

The phenomenon appears not to be limited to alcohol production in yeast, but it forms an important principle in the evolution of living organisms.

The results are presented in a study by Kevin Verstrepen from K.U.Leuven and VIB, a life sciences institute in Flanders, Belgium, Andrew Murray from Harvard University, and Chris Brown, a joint student of Verstrepen and Murray.

Recent research, amongst others by VIB-scientists, showed that the duplication of existing genes can play a crucial role.

One copy can retain the original function of the gene while the new copy may develop a new function. This can sometimes be very different from the original gene.

In the new study, Chris Brown, a PhD student in Verstrepen´s lab, shows that some genes that are closely located in the ends of the chromosomes, are duplicated more often.

The ends of chromosomes, called subtelomeres, seem to function as evolutionary laboratories of our cells.

New genes are continuously developed and tested in these “gene nurseries”.

It appears that duplication at the subtelomeres already occurred in the ancestor of our industrial beer and wine yeasts- Modern strains of beer yeast contain five to ten copies of a prehistoric gene that allows for some sugars to be digested.

Each of these modern copies ensures that yeast can digest a particular sugar, and this is much faster than the prehistoric yeast.

The massive duplications occurred probably around the Cretaceous era (66 to 145 million years ago).

It was no coincidence that this involved the same period in which sweet fruits and grains developed.

The duplication of the genes and the further evolution thereof, allowed yeast cells to digest the different sugars in the fruits.

Thus, the subtelomeric “gene copying laboratory” ensured that yeasts were able to conquer a new niche.

Interestingly, it seems likely that similar subtelomeric gene duplication also stimulates evolution and adaptation in higher organisms, including humans.

The study has been published in the prominent journal Current Biology. (ANI)

Stress a killer for tiny lizards

It’s official: stress is a killer, particularly if you’re a sand lizard that has lost its tail.

Australian and Swedish researchers have found that telomeres, typically associated with ageing in humans, are affected by stress from attack and lead to a shorted lifespan for the tiny Swedish reptile.

Telomeres are sequences of non-coding DNA that cap the ends of chromosomes and contribute to their stability and the genomic integrity of cells.

They have been likened to the tips at the end of the shoelace that stops the shoelace from fraying.

In humans, “fraying” or shortening of telomeres can be increased by “factors leading to genetic erosion,” says lead author Professor Mats Olsson, of the University of Wollongong.

Such factors can include free radicals and other forms of stress.

Professor Olsson and colleagues have looked at how a vital aspect of predator avoidance – tail autotomy, or dropping a tail – is linked to telomere length in the sand lizard, lacerta agilis.

The sand lizard – a small, ground-dwelling lizard found in Sweden – can only regrow its tail once if the whole tail is dropped.

“Once the last original vertebra in the tail is lost, there is no way to drop the tail ‘voluntarily’ under predator attack,” Professor Olsson said.

“This in itself is likely to be highly stressful and seriously compromise survivorship.”

In larger males, which have a much more exposed lifestyle, telomeres were significantly more affected by tail loss.

“Thus, males in the fast lane would be predicted to become more stressed during the mating season, and that is exactly what we see,” the researchers write.

According to the study, males that are engaged in more contests for partners have higher corticosterone levels, which is the hormone involved in stress responses.

“These are exactly the same males in which tail regrowth most strongly seems to compromise telomere length.”

The study appears in the online version of the journal Biology Letters.

Childhood abuse ‘accelerates body’s ageing process’

Washington, March 17 (ANI): Physical or emotional abuse during childhood accelerates the body”s ageing process, according to a new research.

Cellular aging remains somewhat of a mystery, although there is growing evidence that over time, the DNA within cells begins to show signs of aging.

One of these signs is the shortening of telomeres, which are DNA “caps” at the end of chromosomes that promote cellular stability.

Telomere length is a measure of biological aging because telomeres shorten progressively with each cell division.

Shorter telomere lengths have been linked to a variety of aging-related medical conditions including cardiovascular disease and cancer.

Stress and trauma such as childhood abuse and neglect are risk factors for several medical and psychiatric illnesses, and stress is known to promote cellular aging.

So, Audrey Tyrka and her colleagues from Butler Hospital and Brown University examined the DNA of healthy adults who had a history of childhood maltreatment and found they had shorter telomeres than those who did not experience child maltreatment.

Tyrka said that the findings “suggest the possibility that early developmental experiences may have profound effects on biology that can influence cellular mechanisms at a very basic level and even lead to accelerated aging.”

The study has been published in Biological Psychiatry. (ANI)

Three genes linked to Lou Gehrig’s disease identified

Washington, Sep 10 (ANI): Researchers at Michigan Technological University have identified three genes that play a major role in the most common type of amyotrophic lateral sclerosis (ALS), generally known as Lou Gehrig’s disease.

The team of mathematicians, led by Shuanglin Zhang, isolated the genes from the many thousands scattered throughout human DNA.

Zhang noted that the discovery does not mean an end to ALS, but it could provide scientists with valuable clues as they search for a cure.

“I felt very urgent to find the genes for ALS,” Zhang said.

“This is very nice work. It’s very challenging to map genes for complex diseases, and while many statistical methods have been developed, most don’t work well in practice. Zhang’s group has developed a method to detect genes and gene-gene interaction in complex diseases and provided evidence that it works,” said Xiaofeng Zhu, an associate professor of epidemiology at Case Western Reserve University’s School of Medicine.

“Their findings will need to be confirmed by other researchers, but I think this will be very useful for the investigators who are trying to find genes underlying complex diseases such as ALS,” said Zhu.

According to the ALS Association, only about 10 percent of patients have familial ALS, a directly inherited form of the usually fatal neuromuscular disorder, while the remaining 90 percent are diagnosed with the sporadic form of the disease.

While everyone has the three genes in question, but in people with sporadic ALS, they differ from those in people who don’t have ALS.

The mathematicians were not surprised when they tracked down the location of the genes.

“Everybody has 23 chromosomes, and the three genes on chromosomes 2, 4, and 10 interact. If you have this combination of the three genes, you are at high risk of developing the disease. It’s really exciting, especially because my husband has sporadic ALS. Maybe they can find a cure by blocking the genes,” explained Zhang’s wife Qiuying Sha.

ALS destroys the nerves in the brain and spinal cord that control voluntary movement, eventually leading to paralysis.

Zhang’s team used a new statistical method to analyse the genetic codes of 547 individuals, 276 with sporadic ALS and 271 without.

The method, a two-locus interaction analysis approach, allows the researchers to identify multiple genes associated with a complex illness.

The data set they analyzed was provided by National Institute of Neurological Disorders and Stroke (NINDS) Human Genetics Resource Center at the Coriell Institute, a publicly funded “bank” or repository for human cells, DNA samples, clinical data, and other information that aims to accelerate research on the genetics of nervous system disorders.

The study has been published in the open access journal BMC Medical Genetics. (ANI)

MJ’s skin doctor admits he could be Prince, Paris’ dad

London, Aug 28 (ANI): Michael Jackson’s skin doctor has refused to undergo DNA test to confirm if he fathered the star’s two oldest kids, insisting he’s “well aware” he could be the dad.

Dr. Arnold Klein fuelled rumours he’s the biological father of Prince,12, and Paris, 11, when he appeared on TV in the aftermath of Jackson’s 25 June (09) death, and claimed he wasn’t their dad “to the best of my knowledge”.

Klein fuelled the rumours when he turned up unannounced at a guardianship hearing, where the ‘Thriller’ hitmaker’s mother Katherine was awarded custody of the kids.

Although he admitted he could well be the father, Klein says he has no interest in finding out for sure.

“There was a possibility that the two older kids could be biologically linked to Dr. Klein,” the Daily Express quoted Klein’s lawyer Mark Vincent Kaplan as telling UsMagazine.com.

While talking about Klein’s appearance at the custody hearing, the attorney reveals, “Dr. Klein wanted to assert a request that he had concerns.

“He had an agreement with Michael Jackson that if anything happened to Michael Jackson… Dr. Klein would do what he could to see that they were protected.”

The lawyer reveals his client is refusing to undergo a DNA test, insisting Jackson was their true father, and he has no interest in challenging the court’s decision to grant Katherine Jackson custody.

“It would serve no helpful purpose for the children to be distracted from believing Michael Jackson is not the father in every possibility… It is not something Dr. Klein feels he is interested to establish,” said Kaplan.

“It would serve no purpose other than creating distraction or noise. It is not going to help the children, other than to solve the answered question, which is a selfish motive to see who the ultimate provider of the 13 chromosomes (is),” he added. (ANI)

Gene breakthrough could banish inherited diseases

London, Aug 26 (ANI): Researchers at Oregon Health and Science University’s Oregon National Primate Research Center (ONPRC) have developed a new technique that could banish a host of crippling inherited diseases forever.

The landmark research raises the prospect of wiping out diseases passed on from mothers to their children through mutated DNA in cell mitochondria.

“We believe this discovery in nonhuman primates can rapidly be translated into human therapies aimed at preventing inherited disorders passed from mothers to their children through the mitochondrial DNA, such as certain forms of cancer, diabetes, infertility, myopathies and neurodegenerative diseases,” said Shoukhrat Mitalipov, from Oregon Health and Science University (OHSU).

Mitochondria are structures that are found in all cells that provide energy for cell growth and metabolism, which is why they are often called the cell’s “power plant.”

The structures produce energy to power each individual cell. Mitochondria also carry their own genetic material.

When an egg cell is fertilized by a sperm cell during reproduction, the embryo almost exclusively inherits the maternal mitochondria present in the egg. This means that any disease-causing genetic mutations that a mother carries in her mitochondrial DNA can be passed on to her offspring.

OHSU researchers’ method transfers the mother’s chromosomes to a donated egg that has had its chromosomes removed, but which has healthy mitochondria, thereby preventing the disease from being passed on to one’s offspring.

During the research, scientists collected groups of unfertilized eggs from two female rhesus macaque monkeys (monkeys A and B). They then removed the chromosomes, which contain the genes found in the cell nucleus, from the eggs of monkey B, and then transplanted the nuclear genes from the eggs of monkey A into the eggs of monkey B.

Then the eggs from monkey B, which now contained their own mitochondria but monkey A’s nuclear genes, were fertilized. The fertilized eggs developed into embryos that were implanted in surrogate monkeys.

The initial implantation of two embryos resulted in the birth of healthy twin monkeys. These monkeys are the world’s first animals derived by spindle transfer.

Follow-up testing showed that there was little to no trace of cross-animal mitochondrial transfer using this procedure. This shows that the researchers were successful in isolating nuclear genetic material from mitochondrial genetic material during the transfer process.

“In theory, this research has demonstrated that it is possible to use this therapy in mothers carrying mitochondrial DNA diseases so that we can prevent those diseases from being passed on to their offspring,” Mitalipov said.

“We believe that with the proper governmental approvals, our work can rapidly be translated into clinical trials for humans, and, eventually, approved therapies,” Mitalipov added.

The research has been published in the Aug. 26 advance online edition of the journal Nature. (ANI)

Scientists unravel genes linked to lung cancer in smokers

London, Aug 21 (ANI): British researchers claim to have unravelled the genetics underlying a smoker’s risk of developing lung cancer.

Study leader Professor Richard Houlston has identified three areas of DNA that are linked to lung cancer risk in smokers.

Two of them also influence the type of cancer, which develops.

The research team found specific differences associated with lung cancer risk on chromosomes 5, 6 and 15.

It showed that people with genetic changes on chromosome 5 were more likely to develop a type of cancer called adenocarcinoma.

The region highlighted on chromosome 6 appears to influence whether a patient developed adenocarcinoma or another type called squamous cell carcinoma.

And two independent sites on chromosome 15 were found to have a role in whether or not a smoker develops lung cancer.

The researchers suggest that current or former smokers who carry one copy of each of these genetic variants increase their risk of lung cancer by 28pct.

The risk increases to 80pct in smokers who carry two copies of these genetic variants.

“The next step is to dig deeper to pinpoint which gene, or genes in these regions, cause the increased risk of developing lung cancer and how they actually trigger this increase,” BBC News quoted Houlston as saying.

Dr Lesley Walker, director of cancer information at Cancer Research UK who partly funded the research, said smoking was responsible for the vast majority of lung cancers.

“This research shows that inherited genetic variation accounts for some of this risk and the type of lung cancer that develops,” she said.

She added: “The best thing a smoker can do to reduce their risk of lung cancer, and a range of other life-threatening conditions, is to quit.”

The findings appear in Cancer Research journal. (ANI)

Genome duplication responsible for more plant species than previously thought

Washington, August 13 (ANI): In a new research, a team of scientists has found that extra genomes appear, on average, to offer no benefit or disadvantage to plants, but still play a much more important role in the origin of new species than previously thought.

The research was done by scientists from Indiana University Bloomington and three other institutions.

Plant biologists have long suspected polyploidy – the heritable acquisition of extra chromosome sets – was a gateway to speciation.

But, the consensus was that polyploidy is a minor force, a mere anomaly that accounts for 3 or 4 percent of the world’s flowers and ferns.

Now, the first direct, comprehensive survey of polyploid speciation in plant evolution severely challenges that notion.

“In the present paper, we make it clear that it is a common process,” said evolutionary biologist and lead author Troy Wood, who began the research during graduate training at IU Bloomington.

“Fifteen percent of flowering plant species and almost a third of fern species are directly derived from polyploidy,” he added.

The scientists’ exhaustive survey of published phylogenetic and genomic data also shows that plant lineages starting with a polyploid ancestor appear to be no more successful at spawning species than diploid plants, which have two sets of chromosomes.

“The fact that polyploidy seems to have no effect on diversification rates should reduce the number of enthusiastic commentaries about the ‘advantages of polyploidy’,” said IU Bloomington evolutionary biologist and paper coauthor Loren Rieseberg, who supervised the research.

“However, our diversification rate analyses only examined recent polyploids. A future area of research should be to ask whether more ancient polyploidy events have increased diversification rates,” he added. (ANI)

Genes that modulates stress responses identified

Washington, July 14 (ANI): A Baylor University researcher claim to have discovered certain genes that modulates stress responses, which could cause some people to take drugs and consume alcohol.

Dr. Doug Matthews, professor of psychology and neuroscience at Baylor, has found a small section on chromosome one that is responsive to a particular type of stress in animal models.

He then identified the genes in this region that could be responsible for the behavioural response to stress, like alcohol consumption.

“This study gives us insight into a common genetic pathway for stress that might be critical in modulating drug taking behaviour, especially alcohol consumption since many people report drinking alcohol to reduce stress,” said Matthews.

“It also gave us some ideas on where to look in the brain for drug taking behaviour and it provided a method to do so,” he added.

According to Matthews, the researchers used a unique method to do the project by selecting chromosomes from one particular strain of mice, and embed them inside the background of a host strain.

He said that this sophisticated genetic manipulation allowed them to target specific chromosomes so they could get a much more powerful genetic answer.

The findings have appeared in the journal Behaviour Genetics. (ANI)

Are artificial human sperm actually identical to natural kind?

London, July 9 (ANI): Scientists are calling for more tests to ensure that artificial sperm created by some British researchers are identical to their natural counterpart, saying that further proof may make them a valuable tool to understand male infertility.

Karim Nayernia and his colleagues at the University of Newcastle recently treated male embryonic stem cells (ESCs) with a range of substances, which converted them first into germline stem cells, and finally into spermatogonial stem cells.

The spermatogonial stem cells thus created then divided to produce “haploid” spermatocytes with just 23 chromosomes, which went on to mature into sperm.

Other scientists are now calling for more evidence.

“Although they find that some of the sperm cells have tails and can swim, this is not evidence of normality,” New Scientist magazine quoted Robin Lovell-Badge, who studies sperm formation at the UK National Institute for Medical Research in London, as saying.

The seven mouse pups Nayernia’s team produced in 2006, after fusing normal eggs with mouse sperm created in the lab, died within five months because chemical caps called methyl groups had blocked vital genes in the sperm.

He is currently carrying out further tests to determine whether the same thing happens with the human sperm.

The researcher has solved the problem in mice by putting spermatogonial cells into mouse testes before they mature.

“The sperm then have a normal shape and normal methylation patterns,” he says.

He also claims to have developed “artificial testes” to do the same job for humans.

A more distant possibility is the creation of sperm from a woman’s cells, allowing a lesbian couple to have a child.

Nayernia produced spermatogonial stem cells from female ESCs, but they lacked genes needed to mature.

An article shedding light on this field has been published in the journal Stem Cells and Development. (ANI)

Scientists comparing human and canine genomes to find cure for brain cancer

Washington, July 7 (ANI): Researchers at North Carolina State University say that comparing human and canine genomes, they have come to the conclusion that a gene commonly believed to be involved in meningiomas-tumours-which affect the meninges (thin covering) of the human brain, and account for one out of four adult brain tumours-may not be as crucial for tumour formation as previously thought.

“The dog has been man’s best friend for centuries, and now the genome of the dog could well be man’s next best friend,” says Dr. Matthew Breen, professor of genomics at NC State.

“With so much genetic material to consider, one can see why figuring out which genes play a key role in meningiomas is extremely difficult. By looking at tumors seen in both humans and dogs we have a simple way to narrow the search: we compare the affected areas of a human chromosome with related areas on dog chromosomes.

This works because dogs and humans are genetically similar and both get the same kinds of cancers. While we share much of our genetic material, the DNA of a dog is organized differently to our own and this makes it possible to isolate smaller ‘shared’ regions of genetic data rather than looking at an entire chromosome,” he adds.

Breen, NC State colleagues Rachael Thomas and veterinary neurologist Natasha Olby, along with researchers from the University of California-Davis and the Wellcome Trust Sanger Institute in Cambridge, UK shared samples of canine meningiomas for research.

Studies conducted in the past have suggested that a particular tumour-suppressing gene on human chromosome 22, known as NF2, may be a possible contributor to meningioma. It is believed that the deletion of NF2, with its tumour suppressing abilities, may trigger tumour growth.

However, when Breen’s team compared human genome with its canine counterpart, they found that NF2 was rarely affected in dogs with meningioma.

Besides, the research team also looked at gliomas, another kind of brain tumour, and showed common genetic features shared between human and canine tumours that are now under further investigation.

“The data support that dog and human tumors are very similar at the genetic level, so both species will benefit from this research,” Breen says.

“It’s proof of the ‘One Medicine’ concept – the idea that human and animal health relies on a common pool of medical and scientific knowledge and is supported by overlapping technologies and discoveries,” he adds.

A research article on the study has been published in the Journal of Neurooncology. (ANI)

Book debunks the myth that there are only two sexes

London, July 6 (ANI): A Colorado State University expert has debunked the myth that there are only two sexes.

Gerald Callahan, an associate professor of immunology and the public understanding of science at Colorado State University, writes in ‘Between XX and XY: Intersexuality and the myth of two sexes’ that the stereotypical view of two sexes – me Tarzan, you Jane – limits people’s understanding and appreciation of their own biology.

He argues that there is a range of sexual characteristics that stretches from the testosterone-inflated Tarzan to the womanly “perfection” of a stereotypical Jane, and all the variations that lie in between.

“In truth, we are all intersex,” New Scientist magazine quoted him as having written in the book.

The standard model of human development is built on 46 chromosomes, including two that determine sex: XX for female, XY for male.

Callahan, however, insists that not everyone ends up 46XX or 46XY.

According to him, variations in sperm or egg, in the mixing of cells from mother and father and in the cell division that follows can all stir the genetic soup into alternative outcomes.

“(The possibilities) are as grand and as varietal as the fragrances of flowers: 45X; 47XXX; 48XXXX; 49XXXXX; 47XYY; 47XXY; 48XXXY; 49XXXXY; and 49XXXYY,” he writes.

While geneticists are familiar with such variations, says Callahan, the general public is still stuck in a black and white, XX/XY world.

Callahan’s book is spent exploring the understanding of intersexuality, from the physicians of ancient Greece to today’s neuroendocrinologists.

He also weaves in the stories of people who live in the stretch between the classic male and female endpoints. (ANI)

Declining bumblebee populations at greater risk of inbreeding, say researchers

Washington, July 2 (ANI): A new piece of research suggests that inbreeding can trigger a downward spiral of reduction among the already declining bumblebee populations.

Published in the open access journal BMC Evolutionary Biology, the study has for the first time provided proof that inbreeding reduces colony fitness under natural conditions by increasing the production of reproductively inefficient ‘diploid’ males.

The sex of bumblebees is normally determined by the number of chromosome sets an individual receives. Males, born from unfertilised eggs, are haploid (just one chromosome set), while females receive genetic material from a father and a mother and so are diploid (two sets of chromosomes).

However, according to the study, when inbreeding takes place, the likelihood of generating a “freak” diploid male is increased.

Penelope Whitehorn, from the University of Stirling in the UK, led a team of researchers who sought to investigate the effects of a generation of these diploid males on the fitness of bumblebee colonies.

She said: “The study of genetic diversity and inbreeding in bumblebees is currently of particular importance as many species have been suffering from significant population declines. The intensification of agriculture and the associated loss of flower-rich meadows and other habitats on which bumblebees depend has led to isolation of groups of bees and a consequent loss of their genetic diversity, increasing their susceptibility to possible deleterious effects of inbreeding.”

During the study, fertile female bees were mated in the laboratory with either their brothers or with unrelated males.

The queens that established colonies in the lab could be divided into three groups – inbred queens producing diploid males, inbred queens producing normal colonies without diploid males and a control, non-inbred group.

After monitoring the initial founding of the colonies in the lab, the researchers then compared the development and survival of these three colony groups under natural field conditions.

Whitehorn said: “A number of fitness parameters were severely negatively affected by diploid male production, including colony growth rate, total offspring production and colony survival. However, no significant effects of inbreeding in the absence of diploid male production were detected.”

Based on their observations, the researchers have come to the conclusion that diploid males are extremely detrimental for wild bumblebee colonies.

Diploid males are produced at the expense of industrious females, but unlike these female workers, they do not contribute to colony growth and productivity. In fact, they do not function very well as males either, as they are much less fertile than normal males and any offspring they do produce are always unviable or infertile.

The researchers say that diploid males may act as indicators of the genetic health of populations, and that their detection could be used as an informative tool in bee conservation. (ANI)

Genetic map of widespread infection-causing parasite constructed

Washington, June 29 (ANI): In a major achievement, scientists at the Southwest Foundation for Biomedical Research (SFBR) in San Antonio have constructed a genetic map of the parasite that causes schistosomiasis.

Schistosomiasis is a chronic intestinal infection that can damage internal organs and, in children, impair growth and cognitive development.

Schistosome parasites are flatworms that infect more than 200 million people a year worldwide.

“A genetic map is the essential tool needed for finding the genes that are responsible for drug resistance and pathogenesis in this parasite. In the case of drug resistance, identification of underlying mutations is critical for management of this disease,” said Dr. Timothy Anderson, of SFBR’s department of genetics.

He added: “First, identification of mutations allows us to better understand the mechanism of action of the drugs used, and to redesign drugs to restore treatment efficacy. Second, identification of mutations involved allows us to efficiently monitor the spread of resistance in parasite populations using simple molecular methods.”

For the study, the researchers used two adult flatworms to breed 88 S. mansoni offspring.

They then compared the genetic information of the offspring to the parents, and generated a genetic map of chromosomes of the pathogen.

These parasites have a complex lifecycle. Adult male and female worms measuring around half an inch, live in pairs in the blood vessels, and eggs are expelled in the faeces or urine.

The larval parasites initially develop in water snails and human infection occurs when parasite larvae burrow through the skin of people entering the water.

The researchers are planning further research using the genetic map to understand why some parasites cause more pathology than others.

The new study has been published in the journal Genome Biology. (ANI)

Now, test that predicts when a woman will reach menopause

Washington, May 26 (ANI): Scientists have made a new discovery that might be of great help for women planning to have babies later in life.

For the first time, scientists have been able to identify the genetic factors that influence the age at which natural menopause occurs.

It is hoped that this can allow women in their late 30s and early 40s to pinpoint accurately how long they have left in which to conceive and when they should start trying for a baby.

Lisette Stolk, a researcher from Erasmus University Medical Centre in the Netherlands, said at the annual conference of the European Society of Human Genetics that a greater understanding of the factors influencing age at menopause might also help to improve the clinical treatment of infertile women.

Stolk and colleagues analysed genetic data from nine studies involving 10,339 menopausal women.

They found 20 single letter changes in the genetic code that were associated with having an early menopause.

The variants, known as single nucleotide polymorphisms (SNPs), were located at four different sites on chromosomes 19 and 20, two of the coiled packages of DNA that house the genes.

None of the variants had been identified before. What effect they have is unclear, but the scientists suspect they influence the ovaries or the brain.

“We found that the 20 SNPs were all related to a slightly earlier menopause and women who had one of them experienced menopause nearly a year earlier than others,” said Stolk.

“We know that ten years before menopause women are much less fertile, and five years before many are infertile. In Western countries, where women tend to have children later in life and closer to menopause, age at menopause can be an important factor in whether or not a particular woman is able to become a mother,” Stolk added.

Other effects of earlier menopause include an increased risk of the bone disease osteoporosis, the joint disease osteoarthritis and of heart disease, although it can also offer some protection against the risk of breast cancer. (ANI)

Why American Indians have higher rates of cardiovascular and chronic kidney diseases

Washington, April 16 (ANI): Scientists at the University of North Carolina Kidney Center have come up with an explanation as to why American Indians at a greater risk of developing proteinuria – a condition that increases the risk of cardiovascular disease and chronic kidney disease (CKD) – than other groups.

Dr. Amy Mottl and her colleagues say that these differences exist as genetic variation likely accounts for part of their increased risks.

During a study, Amy and her colleagues tried to find out whether they could identify the genetic causes of American Indians’ increased risk for proteinuria.

Studying about 3,500 individuals from 13 American Indian tribes enrolled in the Strong Heart Family Study funded by the National Heart, Lung and Blood Institute, the researchers found multiple chromosomal regions that may possess genes that influence variation in proteinuria, especially in the setting of diabetes or hypertension.

Amy said that the findings of her team were preliminary, and that further research was required to detect which genes influence one’s proteinuria risk.

“Further exploration of the candidate genes underlying the chromosomes implicated in our study is warranted,” the authors wrote.

The researchers believe that their work may be helpful in advancing scientists’ understanding as to how proteinuria arises, and, thereby, enable the development of new strategies for prevention and treatment.

While this study focused on American Indians, its findings likely apply to the general population as well, where the prevalence of proteinuria is rising.

The study has been published in the Journal of the American Society of Nephrology (JASN). (ANI)

World’s tallest teenagers to appear in TV documentary

London, Apr 8 (ANI): At 7ft 4 1/2ins, Brenden, from Ellensburg, Washington, is the tallest boy in the world, and will be featured in an ITV1 documentary ‘Superhuman’, along with other adolescents who stand higher in a crowd.

Most of the teenagers in the documentary tower over Peter Crouch, the 6ft 7ins England footballer, and have to have custom-made beds, clothes and houses to accommodate their frames.

Although Brenden was born a normal 7lb 4oz, at 12 months he was the size of a three-year-old.

And by the time he turned eight, he was as big as an adult, reports the Telegraph.

Doctors diagnosed his abnormal height to a problem with his chromosomes, and have now slowed down the rate at which he is getting taller.

Another teenager is 17-year-old Thai Malee Duangdee, who is the tallest girl in the world with a height of 6ft 10ins.

Also appearing in the programme will be Marvadene Anderson, 15, who stands at 6ft 9 1/2ins and has been named the second tallest girl in the world.
Britain’s tallest family, the Van Neses, will also appear in the documentary.

The family comprises of Dad Frank, 6ft 10ins, mum Miriam, 5ft 11ins, sons Vincent, 16, 6ft 10ins, Lucas, 15, 6ft 8ins and Franklin, 13, 6ft 1in. Daughter Naomi, 11, is 5ft 9ins. (ANI)

Study sheds light on egg cells’ unique ability to ensure that sperm don’t get too old

Washington, March 26 (ANI): While it is thought that men remain fertile throughout life as compared to women, Swedish researchers have now shown that a fertilising sperm can get help from the egg to rejuvenate.

Researchers at the Sahlgrenska Academy, University of Gothenburg, say that their finding is an important step towards future stem cell therapy.

The researchers highlight the fact that the risk of chromosomal abnormalities in the foetus is highly correlated to the age of the mother, but is nearly independent of the age of the father.

According to them, one possible explanation is that egg cells have a unique ability to reset the age of a sperm.

“We are the first to show that egg cells have the ability to rejuvenate other cells, and this is an important result for future stem cell research,” says Associate Professor Tomas Simonsson, who leads the research group at the Sahlgrenska Academy that has made this discovery.

The ends of the chromosomes called “telomeres”-which are important for the genetic stability of the cell and they act as a DNA clock that measures the age of the cell-become shorter each time a cell divides, due to which the cell stops dividing and dies.

The researchers say that their finding that the egg cell can extend the telomeres of a fertilising sperm cell attains significance for the development of stem cell therapy, which involves replacing the cell nucleus in unfertilised egg with a nucleus from a somatic cell that has come from a patient who needs a stem cell transplantation.

As soon as the cell has divided a few times, it is possible to harvest stem cells, which are then allowed to mature to the cell type that the recipient needs.

“The genetic stability of the transplanted cells has been a serious concern up until now, and it was feared that the lifetime of these cells would depend on the age of the cell nucleus that was transferred. Our results suggest that this is not the case,” says Tomas Simonsson. (ANI)

Immune cells in rheumatoid arthritis patients have prematurely aged chromosomes

Washington, Mar 5 (ANI): Scientists at Emory University School of Medicine have discovered that T cells, or white blood cells, from patients with the autoimmune disease rheumatoid arthritis have prematurely aged chromosomes due to lack of structures called telomeres.

elomeres are structures that cap the ends of cells’ chromosomes, grow shorter with each round of cell division unless a specialized enzyme replenishes them.

It is important to maintain telomeres as they are thought to be important for healthy aging and cancer prevention.

T cells from patients with rheumatoid arthritis were found to have trouble turning on the enzyme that replenishes telomeres, when compared with cells from healthy people.

Reversing this defect could possibly help people prone to the disease maintain a balanced immune system.

Senior author Cornelia Weyand, MD, PhD said that in rheumatoid arthritis, T cells are chronically over-stimulated, invading the tissue of the joints and causing painful inflammation.

She claimed that in childhood, new T cells are continually produced in the thymus, but after about age 40, the thymus “involutes” – or shrinks and ceases to function. After that, the immune system has to make do with the pool of T cells it already has.

“What we see in rheumatoid arthritis is an aged and more restricted T cell repertoire. This biases the immune system toward autoimmunity,” she said.

Intrigued by earlier studies claiming that in rheumatoid arthritis, T cells tend to shift the molecules on their surface and function differently, the researchers wanted to study the mechanisms of T cells’ premature aging.

They found the answer in telomerase, the enzyme that renews telomeres and is necessary to prevent loss of genetic information after repeated cell division.

Telomerase adds short repeated DNA sequences to the ends of chromosomes to protect them. The enzyme is active in embryonic development but is usually switched off in adult cells. Many cancer cells reactivate it to enable runaway growth.

T cells are some of the very few cells in adults that can turn on telomerase when stimulated, probably because they have to divide many times and stay alive for decades.

Researchers found that T cells from patients with rheumatoid arthritis make 40 percent less telomerase enzyme when stimulated.

The cells came from 69 patients, 92 percent female, with an average age of 50, and were compared with cells from healthy people with similar demographics.

By shutting off a gene encoding part of the enzyme normal T cells were made vulnerable to programmed cell death, and transferring telomerase into patients’ T cells rescued them from dying.

Scientists said that the finding suggests that restoring defective telomerase to T cells could possibly help “reset” the immune system in rheumatoid arthritis.

The results are published online in Proceedings of the National Academy of Sciences. (ANI)

Now, a technique to pick healthiest sperm for improved IVF treatment

Washington, Feb 26 (ANI): In a bid to revolutionise in vitro fertilization (IVF) treatment, Brit scientists have developed a new technology, called Raman spectroscopy, to find sperm with healthy, intact DNA for better chances of a healthy embryo.

Usually, infertile men with low sperm count or abnormal sperms opt for IVF, in which scientists use light microscopes to find any sperm cell, and then inject it directly into an egg to fertilize it.

But the biggest shortcoming with this method is that broken sperm often means broken DNA.

And Alistair Elfick, a professor at the University of Edinburgh in the United Kingdom, who developed the technique using Raman spectroscopy, said that the DNA, and not the sperm cell itself, is what is really important for a developing embryo.

“It’s interesting research because is shows that there are finer distinctions for sperm other than dead or alive,” Discovery News quoted Michael Morris, a Raman spectroscopy expert at the University of Michigan who was not involved in the research, as saying.A sperm cell is pretty stripped down. The DNA has no explicit role in delivering itself, it’s just the payload,” said Elfick.

While a light microscope kicks a sperm cell’s metaphorical tires, Raman spectroscopy pops the trunk to directly examine the DNA payload.

In Raman spectroscopy, the scientists shine a beam of light on the 23 chromosomes enclosed in the head of the sperm.

As damaged DNA refracts light differently than intact DNA, the researchers can examine the resulting light to determine which DNA is the most likely to lead to a healthy human embryo.

However, when it comes to put the theory into practice, it’s another picture altogether.

To date, scientists haven’t injected Raman spectroscopy-certified sperm into eggs and examined how many more embryos are created or how healthy they are.

There are many limitations to the technique as Raman spectroscopy can only examine tens to hundreds of sperm cells at a time, which may not be a big problem for many infertile men, as this is also roughly the number of sperm they can produce during an ejaculation.

While some scientists fear injecting Raman-examined sperm into an egg, Alistair and Morris are confident that the energy contained in the laser beam is too small to cause any permanent damage to the sperm cell.

But according to Max Diem, a professor at Northwestern University who uses Raman spectroscopy to examine human egg cells, useful reading will require potentially harmful amounts of laser energy.

“This is not just around the corner for couples,” said Diem.

He stressed that more testing is necessary before any Raman spectroscopy examined sperm and egg union is placed into a human uterus. (ANI)