2, June 2014

Subtle changes in DNA determine our hair colour

Washington: Researchers have claimed that a molecule critical to stem cell function plays a major role in determining human hair color.

The study describes for the first time the molecular basis for one of our most noticeable traits. It also outlines how tiny DNA changes can reverberate through our genome in ways that may affect evolution, migration and even human history.

David Kingsley , PhD, professor of developmental biology, said they've been trying to track down the genetic and molecular basis of naturally occurring traits - such as hair and skin pigmentation - in fish and humans to get insight into the general principles by which traits evolve.

He said now the find that one of the most crucial signaling molecules in mammalian development also affects hair color.

The researchers found that the blond hair commonly seen in Northern Europeans is caused by a single change in the DNA that regulates the expression of a gene that encodes a protein called KITLG, also known as stem cell factor.

This change affects how much KITLG is expressed in the hair follicles without changing how it's expressed in the rest of the body. Introducing the change into normally brown-haired laboratory mice yields an animal with a decidedly lighter coat - not quite Norma Jeane to Marilyn Monroe, but significant nonetheless.

The study shows that even small, tissue-specific changes in the expression of genes can have noticeable morphological effects. It also emphasizes how difficult it can be to clearly connect specific DNA changes with particular clinical or phenotypic outcomes. In this case, the change is subtle: A single nucleotide called an adenine is replaced by another called a guanine on human chromosome 12.

The change occurs over 350,000 nucleotides away from the KITLG gene and only alters the amount of gene expression about 20 percent - a relatively tiny blip on a biological scale more often assessed in terms of gene expression being 100 percent "on" or "off."

The study has been published online in the journal Nature Genetics.

Source: www.zeenews.india.com

02.06.2014

Laser to help you say goodbye to dentist's chair

Washington: Anyone who has had a root canal done knows how painful the procedure can be.

But a dental condition that may require one to undergo root canal may no longer give patients sleepless nights as researchers have found that exposing cells on the inside of a tooth to weak laser light stimulates the growth of dentin - the substance that makes up much of a tooth's structure.

Low-power light could trigger stem cells inside the body to regenerate tissue, the study said.

"Our treatment modality does not introduce anything new to the body, and lasers are routinely used in medicine and dentistry, so the barriers to clinical translation are low," said David Mooney, a professor at the Harvard School of Engineering and Applied Sciences (SEAS) in the US.

So far, experiments have been done on rats and mice but the researchers have tested the technique on human cells in culture, and it seems to work, said Priveen Arany, an assistant clinical investigator at the National Institutes of Health.

Researchers took rodents to the laboratory version of a dentist's office to drill holes in their molars, treat the tooth pulp that contains adult dental stem cells with low-dose laser treatments, applied temporary caps, and kept the animals comfortable and healthy.

After about 12 weeks, high-resolution x-ray imaging and microscopy confirmed that the laser treatments triggered the enhanced dentin formation.

The new work marks the first time that scientists have gotten to the nub of how low-level laser treatments work on a molecular level, and lays the foundation for controlled treatment protocols.

A root canal is necessary when too much of a tooth is infected or damaged, and there is not any way to prevent the problem from getting worse (other than removing the tooth entirely).

The findings appeared in the journal Science.

Source: www.zeenews.india.com

02.06.2014

Confidence doesn’t come when we have Answers..It comes only when we are ready to face all the QUESTIONS…!