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ScienceDaily (Jan. 20, 2009) — Scientists at the Centre for Addiction and Mental Health (CAMH) have detected evidence that DNA may not be the only carrier of heritable information; a secondary molecular mechanism called epigenetics may also account for some inherited traits and diseases. These findings challenge the fundamental principles of genetics and inheritance, and potentially provide a new insight into the primary causes of human diseases.

Research conducted by a team in Switzerland suggests that a family of genes involved in regulating the expression of other genes in the brain is responsible for helping us deal with external inputs such as stress. Their results, appearing in the December 11 advance online version of the journal Neuron, may also give a clue to why some people are more susceptible to anxiety or depression than others. The researchers from EPFL and the National Competence Center "Frontiers in Genetics" studied the role of a family of genes known as KRAB-ZFP, which acts like a group of genetic censors, selectively...

The Delicate Balance of Ear Crystals by Brian Thomas, M.S. UCLA researchers have discovered that tiny crystals called otoliths—necessary parts of a properly functioning inner ear—form not as the direct result of a gene product, but rather as the result of the physical, swaying motion of hair-like cilia during development. As adult vertebrate bodies move about, otoliths are pulled by gravity and enable the detection of movement, which is vital for maintaining balance. The researchers studied these crystals in fish embryos, where they accumulate as gelatinous proteins mixed with calcium carbonate. When fully and properly formed, the crystals lie atop...

ScienceDaily (Dec. 2, 2008) — A stunning discovery based on epigenetics (the inheritance of propensities acquired in the womb) reveals that consuming choline—a nutrient found in eggs and other foods—during pregnancy may significantly affect breast cancer outcomes for a mother's offspring. This finding by a team of biologists at Boston University is the first to link choline consumption during pregnancy to breast cancer. It also is the first to identify possible choline-related genetic changes that affect breast cancer survival rates. "We've known for a long time that some agents taken by pregnant women, such as diethylstibesterol, have adverse consequences for...

Mice eating high-fat foods confer changes on at least two subsequent generations. You are what you eat, and so are your progeny and, perhaps, your progeny's progeny — at least, if you're a mouse. According to research presented at the Society for Neuroscience's 38th annual meeting in Washington DC held from 15–19 November, mice fed on a high-fat diet throughout their pregnancies and suckling had offspring that were larger than normal — a trait that was also passed on to their offspring's offspring. It is the first time that a gestating mother's diet has been shown to confer this trait...

The US National Institutes of Health (NIH) handed out the first payments in a multi-million-dollar project to explore epigenomics last month. But some researchers are voicing concerns about the scientific and economic justification for this latest 'big biology' venture. Epigenetics, described as "inheritance, but not as we know it"1, is now a blisteringly hot field. It is concerned with changes in gene expression that are typically inherited, but not caused by changes in gene sequence. In theory, epigenetic studies can help explain how the millions of cells in the human body can carry identical DNA but form completely different cell...

Researchers pinpoint protein 'boss' that controls gene expression. Link to Getty photo from a microscope Will it spread? One protein controls the expression of many genes that dictate whether breast cancer will metastasize. GettyA protein that determines whether breast cancer will spread and become deadly has been found. Researchers say that the protein, which is found inside the nuclei of cells, would be difficult and potentially dangerous to target with drugs. But monitoring for the protein could help patients to know how dangerous their cancer is before it spreads elsewhere, and help them to decide which treatment to chose. Because...

Really? THE FACTS It is a basic tenet of human biology, taught in grade schools everywhere: Identical twins come from the same fertilized egg and, thus, share identical genetic profiles. But according to new research, though identical twins share very similar genes, identical they are not. The discovery opens a new understanding of why two people who hail from the same embryo can differ in phenotype, as biologists refer to a person’s physical manifestation. The new findings appear in the March issue of The American Journal of Human Genetics, in a study conducted by scientists at the University of Alabama...

It is now clear that genetics won’t be able to answer all of our questions about human development and disease. These basic biological processes rely heavily on epigenetics – the ability to ‘fine-tune’ the expression of specific genes. This regulation of gene expression is essential for defining cellular identity and the dysregulation of these processes results in a variety of human diseases. Therefore, understanding these mechanisms will not only enhance our basic knowledge but will also lead to the improved detection, therapy and prognoses of several human diseases. ... The histone code hypothesis predicts that the post-translational modifications of histones,...

Environment can change the way our genes work Environmental factors such as stress and diet could be affecting the genes of future generations leading to increased rates of obesity, heart disease and diabetes.A study of people suffering post-traumatic stress disorder (PTSD) after the 9/11 attacks in New York made a striking discovery. The patients included mothers who were pregnant on 9/11 and found altered levels of the stress hormone cortisol in the blood of their babies. This effect was most pronounced for mothers who were in the third trimester of pregnancy suggesting events in the womb might be responsible....

All brain cells are the same, genetically speaking. Yet somehow they play vastly different roles, some directing movement, others participating in language or thought. Now, a study finds that a chemical known to turn genes on and off may be partially responsible for this division of labor. The results, researchers suggest, could help scientists better understand psychiatric and neurological diseases. It takes more than genes to make people who they are. Identical twins, for example, can look and act differently even though they share the same DNA (ScienceNOW, 5 July 2005). Environmental factors likely contribute to this variation, but it...

The battle of the sexes extends all the way to our chromosomes. In some cases, the copy of a gene inherited from one parent shuts down, leaving just the copy from the other parent active and upsetting the classic rules of inheritance. Now researchers have come up with the first comprehensive map of these so-called imprinted genes in humans. Many of them lie in regions of chromosomes implicated in disease and may be involved in problems such as autism and obesity. Geneticists discovered imprinting in 1991 and now know that defects in imprinted genes lead to abnormal development and to...

Scrutinizing the first days of development in abnormal embryonic stem cells, researchers have uncovered a basic mechanism underlying fragile X syndrome, the most common inherited cause of mental retardation in boys. "It could have important implications for treatment," says W. Ted Brown, cochair of the scientific committee of the National Fragile X Foundation, which helped fund the work. The research also highlights the value of embryonic stem cells for studying genetic diseases, says Yang Xu, a stem cell researcher at the University of California, San Diego. Fragile X syndrome is caused by a mutation in a gene called fmr1. By...

A difference of only a few percent in DNA sequence is thought to separate the human and chimp genomes. New research published in Genome Biology identifies the subset of sequences that may have driven the evolution of our two species.The researchers propose that the key changes lie in regions of our genome that control the activity of genes. It is managers of the genome, rather than the workforce, that have been most responsible for differences between chimps and humans.A team led by scientists from the Wellcome Trust Sanger Institute looked at DNA elements called conserved non-coding regions (CNCs) in human,...

A cloning experiment in mice indicates that for one type of cancer, at least, cancerous cells may be able to revert to normal. But the study does not reveal a way to cure cancer. Instead, it addresses a theoretical question about the genetic nature of one type of cancer. In their experiment, published in the current issue of the journal Genes and Development, the investigators cloned mouse embryos from a melanoma skin cancer cell. Using cells from these embryos, they created healthy adult mice who had some cells derived from the cloned cancer cells, showing that malignancy is not the...

"The genetic sequence is essentially fixed for life, but we believe epigenetic marks are more subject to change," says Feinberg. "The IHF collaboration will let us really test the stability of epigenetics and the passage of those marks from parents to child, perhaps even over successive generations." At the heart of the center's work is epigenetics' importance in proper cell function and in development. One example of epigenetics is "imprinted" genes--genes whose activity is determined not by the regular dominant and recessive rules of Mendel's genetics, but solely by which parent provided the gene copy. For example, for some...