The development of baby teeth depends on several newly identified genes.

By analyzing the genetic code of 6,000 people in Finland and the United Kingdom, researchers found gene variants linked with the time the first tooth appears and with the number of teeth by age one.

The findings appear in Friday's issue of the journal PloS Genetics.

"Our findings should provide a strong foundation for the study of the genetic architecture of tooth development, which as well as its relevance to medicine and dentistry, may have implications in evolutionary biology since teeth represent important markers of evolution," Marjo-Riitta Jarvelin of the School of Public Health at Imperial College London and her colleagues concluded.

One of the identified genes was associated with a 1.35 times higher risk of requiring costly orthodontic treatment by age 30, the researchers found.

Previous studies have linked some of the genes with the development of the skull, jaws, ears, fingers, toes and heart.

"We hope also that these discoveries will increase knowledge about why fetal growth seems to be such an important factor in the development of many chronic diseases," Jarvelin said in a release.

The discovery may lead to innovations in the early treatment and prevention of congenital dental problems, the researchers said.

More than 30 years after the birth of the first "test tube baby," medical researchers and fertility specialists reported that these so-called designer babies are likely to be healthy with few medical differences between them and children conceived naturally.

"By and large, the kids are just fine," Carmen Sapienza, a geneticist at Temple University in Philadelphia, told reporters at the annual meeting of the American Association for the Advancement of Science, according to ScienceNOW. Sapienza and other experts were speakers at a symposium about the health and genetic issues of children conceived by in vitro fertilization and other assisted reproductive technologies. Since the first such conception in 1978, several million children have been conceived using such technologies, and in some countries they account for up to 4 percent of all births.
But using such reproductive technologies makes a difference in the transfer of genetic materials and in normal genetic mutation, leading scientists to wonder what the real-life ramifications of that may be. Despite a small increase in congenital abnormalities and an increased risk of low birth weight and premature birth, researchers at the conference in San Diego concluded that the techniques are effective and relatively safe, according to an abstract of the symposium.

There are known concerns, however. The higher incidence of low birth weight and premature birth is troubling because it can cause an increase in childhood illness and neurological problems such as cerebral palsy, and premature babies have an increased risk of problems later in life.

Some studies also show an increased malformation rate, according to the abstract. There is, however, no evidence of developmental or motor delay in children born after the 32nd week of pregnancy. The genetic differences noted between children conceived using assisted reproductive techniques and those conceived naturally have been implicated in metabolic disorders such as obesity and type II diabetes, which is usually developed in adulthood, according to the abstract.

Researchers cautioned that the majority of IVF babies are in their twenties and none is older than early thirties, so long-term problems would not yet have shown up.

"Progressive walking" combined with glucosamine sulphate supplementation has been shown to improve the symptoms of osteoarthritis. Researchers writing in BioMed Central's open-access journal Arthritis Research and Therapy found that patients who walked at least two bouts of 1500 steps each on three days of the week reported significantly less arthritis pain, and significantly improved physical function.

Dr Kristiann Heesch worked with a team of researchers from The University of Queensland, Australia, to carry out the trial in 36 osteoarthritis patients (aged 42 - 73 years). All patients received the dietary supplement for six weeks, after which they continued to take the supplement during a 12-week progressive walking program. The program, called Stepping Out, includes a walking guide; a pedometer; weekly log sheets and a weekly planner, all intended to help patients adopt the exercise regime.

Seventeen patients were randomly assigned to walk five days per week, while the remaining 19 were instructed to walk three days a week.

The team found that both groups achieved significant improvement in their symptoms, however being encouraged to walk five days a week was not more effective than being encouraged to walk three days. "These findings are not surprising given that the three-day and five-day walking groups did not differ significantly in the mean number of days actually walked per week, the mean number of daily steps walked, nor their weekly minutes of physical activity," Dr Heesch said. "They provide preliminary evidence that osteoarthritis sufferers can benefit from a combination of glucosamine sulphate and walking 3000 steps per day for exercise, in bouts of at least 1500 steps each, on at least three days per week".

This amount of walking is less than current physical activity recommendations for the general population, but follows the recommendations for people with arthritis.

A British-American research team has created female mosquitoes incapable of flight using a genetic engineering trick that some scientists hope to use in India to control mosquitoes that spread dengue.

Researchers at Oxford University and the University of California, Irvine, have genetically altered male mosquitoes so that they pass on a gene that selectively disables only their female progeny to make them flightless.

Their work, reported on Monday in the Proceedings of the National Academy of Science, is part of an effort to curb mosquito population by genetically disabling female mosquitoes that feed on human blood and transmit diseases. Male mosquitoes do not bite humans or other animals. The scientists have developed two strains of genetically disabled Aedes aegypti, the mosquito that carries viruses that cause dengue and other viral diseases.

"Flightless females cannot escape predators, seek hosts, or mate - therefore these females will die without producing progeny and the size of the wild population will decline," said Luke Alphey, a team member and a visiting professor at Oxford.

"We release males who carry a gene that makes females flightless. When they mate with wild females, their daughters are flightless. This decreases the number of females in the next generation causing the population shrink," Alphey said.

The researchers hope that repeated releases of such altered males will continue to reduce the wild population of female mosquitoes until their number falls below the critical threshold required to cause major public health outbreaks of diseases.

About five years ago, Alphey and his colleagues had used similar genetic engineering technology to develop a strain of Aedes aegypti called OX513A, genetically-disabled to ensure that its larvae do not survive into adulthood.

But a senior government scientist involved in mosquito control in India appeared sceptical, arguing that while he appreciates the novelty in this research, it is a high technology strategy for a problem for which solutions are already available .

"India had tried a slightly different method to suppress mosquito populations using sterile males in the 1970s - but it failed miserably," said a researcher at the National Institute of Malaria Research, who requested anonymity.

"Continuous infiltration of wild mosquitoes from outside the experimental area frustrated attempts to curb populations," he said, describing the results of the failed field experiments in northern India during the 1970s.

But theoretical studies have suggested that the new approach based on genetically disabled mosquitoes - to remain flightless or to die as larvae - can lead to strong suppression of wild populations in over six to nine months in an area of the size of a city.

"These mosquitoes represent a replacement or a supplement to insecticides and result in decreased mosquito populations," said Anthony James, a team member and molecular biologist at the University of California, Irvine.

The OX513A strain has been tested in laboratories in France, the UK, and in semi-field conditions in Thailand and Malaysia, said Seshadri Vasan, head of public health with Oxitec, a company set up by Alphey to pursue novel insect-control technologies.

The International Institute of Biotechnology and Toxicology, a non-governmental research centre in Chennai, has received permission from Indian biotechnology regulators to import the OX513A strain for studies in a contained laboratory, Vasan said.

Scientists concede that there are concerns about potential ecological impacts of reducing mosquito populations, but point out that such possible consequences need to be considered on a case-by-case basis for each pest and each region. "But, mosquitoes are invasive species whose spread is facilitated by humans.

"There is no evidence that they are a keystone species in any natural ecological habitat,".

Alphey said the Aedes aegypti mosquito is native to Africa and was over the centuries inadvertently carried by humans into Asia and the Americas. "As a recent invader, one would not expect native species to be dependent on it. Indeed eliminating invasive species would be considered environmental remediation," Alphey said.

An Indian malaria researcher cautioned that flightless mosquitoes could adapt and turn into crawling insects that would still seek out bloodmeals. "Insects can adapt really well to different situations," he said.

"There's no single magic solution for mosquito control," said Vasan. Colonisation of OX513A strain has been completed at the IIBAT and a panel of government scientists is expected to instruct the institution on the next steps, he said.

A study of 95,000 people has revealed that people take the risk of developing stones in kidney at twice the speed by being obese.

It was further examined that one in 20 had developed stones compared to one out of 40 who had normal weight. The condition of kidney stones is very painful and might even involve surgical procedure if it gets too severe.

However, this finding also contradicts the basic assumption that the chances of getting stones in the kidney increases as the weight increases from the 'mildobese stage' to the 'threshold obese stage'. The risk actually depends on the Body Mass Index or the BMI. BMI is the height to weight ratio of the body at different age levels.

During the hour of the study, about 2.6 per cent of the healthy people had developed the illness and the figure actually rose to 4.9 per cent when they considered an obese person who's BMI score was more than 30.

It is sighted that hormones tend to increase the weight and would possibly be behind the reason to gain weight or 'the morbid obesity'. Speculations suggest that unhealthy lifestyle also aids in gain of weight at a very fast rate.