Archive for October, 2009
Who’s My Other Mommy?
Oct 26th
Fraternal Rhesus Macaque twins, Mito and Tracker, have two different DNA mommies: their mother’s chromosomal DNA was injected into enucleated egg cells belonging to another Rhesus monkey female prior to fertilization. The eggs were fertilized, in vitro, with donor sperm and implanted in yet another female who carried the healthy twins to term.
The nucleus, where chromosomal DNA is stored and protected, is not the only source of DNA in a mammalian cell. Mitochondria have their own 16,569 bp genomes encoding 37 genes involved in the production of biological energy, ATP. Mutations in these genes have been linked with human diseases More >
Trembling Hands and … Genes?
Oct 23rd
Fragile X Tremor/Ataxia Syndrome (FXTAS) is among the most prevalent heritable neurodegenerative disorders. Its symptoms usually develop in men 50 years of age or older and include tremors in arms and hands, balance problems (ataxia), numbness in the extremities, mood instability, short-term memory loss, and gradual intellectual decline. The prevalence of FXTAS is about 2-5 persons per 10,000 in the general population.
The underlying cause for FXTAS is a mutation in the gene for Fragile X Mental Retardation Protein (FMRP), which is located on the X-chromosome; its protein product, Pur-α is essential for normal neural function. Scientists have recently determined the three-dimensional structure More >
The Continuum of Eugenics Practice
Oct 22nd
Francis Galton, the English scientist who coined the term, defined eugenics as “the agencies under social control that improve or impair the racial qualities of future generations either physically or mentally.” Charles Davenport, the father of the American eugenics movement called it simply “the self direction of human evolution.”
These definitions stress differences that occupied either end of a continuum of eugenics practice. At one end, Galton’s definition stressed social control, or laws, to control human reproduction. At the other end, Charles Davenport’s stressed an individual’s own control over their reproduction. Social control ultimately embodied “negative eugenics”– limiting mixed race marriages, More >
Canines and cancer
Oct 21st
For my blog, I thought I would talk a bit about dogs and cancer. Why, you might ask? I’m not a dog owner, but recently a few stories about dogs and cancer were brought to my attention and I thought they might be interesting to others.
You may not know this, but dogs can actually smell some cancers. It doesn’t even take a sophisticated sniffer dog to do this: even some household dogs can be trained to tell the difference between the odor of a normal person and that of a person with lung cancer. In theory, your dog Max could More >
White Matter Matters!
Oct 19th
Can you change the structure of your brain with practice? A slew of papers in the last decade affirm that yes, you very much can. Probably the best known is a study by Maguire and colleagues, who found structural differences in the hippocampi of London taxi drivers — presumably the result of having to learn London’s 25,000 streets. [We turned the Maguire et al. study into an online experiment, which you can play here].
To date, every study that identified practice-related changes in brain structure located these changes in grey matter. Now, for the first time, a paper by Scholz and colleagues More >
Pharmacowhat? Pharmacogenetics!
Oct 15th
Your genes affect not only how you look and your predisposition to disease, but it would appear that they also affect your responsiveness to different drug treatments following disease onset.
In the emerging field of pharmacogenetics, scientists study genome variations and correlate them with drug treatment response. For example, variations (also called polymorphisms) in genes encoding enzymes involved in drug metabolism have been found to affect the activation, deactivation, and toxicity of drugs used to treat cancer, heart disease, and psychiatric disorders. Recently, scientists found that DNA sequence can also be used to predict responsiveness to current Hepatitis C treatment (a More >
Hildegard’s Dilemma
Oct 14th
Hildegard von Bingen, a 12th century nun was celebrated for her intellect, writings, and notably for her extraordinary visions – also known as migraine auras. Ask any migraineur about the scintillating scotomas preceding a migraine, and you’re likely to receive a flinching look in return. Migraines with aura are chronic headaches characterized by specific neurological symptoms – visual disturbances, nausea, sensitivity to light, sounds, smells, and usually accompanied with an unilateral blinding headache—the hallmark TKO of migraines. Now it appears that female migraineurs might find an unexpected silver lining in the migraine cloud – researchers at the Fred Hutchinson Cancer More >
Diverse Proteins
Oct 14th
The instructions for life are carried in the DNA of our cells. All day long, our cells read the information in our DNA and make proteins. While DNA contains recipes for how life works, proteins are molecules that I consider the “doers” in our cells.
Protein is a broad category that includes enzymes and hormones. When you eat an apple, your body produces enzymes to break down that apple and build new products for your body. If you have a lot of glucose (a type of sugar) in your blood, the cells in your pancreas will read the gene for insulin More >
The Future of Medicine
Oct 13th
Emerging DNA technologies continue to offer us many new insights into our genome, and its implications on human disease. One area that is currently under much scrutiny is how different patients are responding differently to certain drug treatments. Researchers are now finding that some people have a genetic predisposition to how they will react to a drug. If there is some way that we could detect this in the doctor’s office as they are writing the prescription, it would help save time and lives as we try to combat these diseases.
The Imperial College London and its affiliate-company DNA Electronics have More >
The fight against Huntington’s
Oct 9th
Huntington’s disease (HD) is an inherited disease, characterized by the wasting away of certain nerve cells in the brain. If a person inherits only one mutated copy of the Huntingtin gene they develop the disease. One who is born with the defective gene responsible for the disease may not show any of the symptoms until middle age. Symptoms could consist of balance issues, uncontrolled movements or clumsiness. In the progression of the disease one may also loose the capability to talk or even walk.
Medivation, Inc. and Pfizer Inc. have publicized that the start of phase three trials in the usage More >
