Archive for September, 2011
IQ Tests as a Measure of Intelligence
Sep 28th
Many of the old theories relating to eugenics were tied deeply to intelligence levels as predicted by IQ tests. As a matter of fact, popular IQ tests that are still in use today have their roots in the eugenics community. But just how well does an IQ test fare as a measure of intelligence?
Before we can measure something, intelligence in this case, we must define it. This presents a challenge on its own. How do we define intelligence? Merriam-Webster defines intelligence as:
- the ability to learn or understand or to deal with new or trying situations. also: the skilled use of More >
Will insulin come to the rescue of AD patients?
Sep 27th
Alzheimer disease (AD) is a neurodegenerative disease of the brain that is divided into early- and late-onset groups. AD is characterized by the build up of amyloid plaques, neurofibrillary tangles and the loss of connections between neurons. It is the most common type of dementia especially in the elderly. The exact causes of AD are elusive at the moment but are most likely the result of genetics and other factors. Scientist have been working hard to identify individual and or groups of genes responsible for the disease. Although the scientific community has identified may genes involved in early and late More >
Different sides of the same coin; twins and epigenetics
Sep 23rd
Most people are aware that monozygotic (identical) twins share the exactly the same DNA, but it might be surprising to know that traits and diseases with genetic components can vary between these twins. In the case of some psychiatric disorders with strong genetic components, there are many pairs of identical twins in which only one twin actually develops the disease. In bipolar disorder for example a monozygotic twin has only a 40%-70% chance of also having bipolar disorder if their twin has been diagnosed. If bipolar disorder really has a strong genetic component, then why isn’t this number 100%?
Of course, we More >
Can I Teach That?
Sep 21st
Recently I worked with a group of graduate students who volunteered to be science mentors for students in New York City. They were being trained in a small set of hands-on labs designed to introduce genetics in an engaging, informal environment. At some point during the training, we touched upon genetic mutations and variation. I mentioned that it was a perfect segway into discussion of natural selection and evolution. One participant raised her hand and asked, “Are we allowed to teach that?” My initial response was surprise. I said, “Of course!” It is unfortunate though, that as science educators we should even More >
Brain tumors snack on cholesterol
Sep 19th
We all know cholesterol can be bad for us, and we need to watch our intake of eggs, cream and butter. But scientists have just discovered that some brain cancer cells love to snack on cholesterol too.
Researchers at the University of California Los Angeles and Ohio State University Comprehensive Cancer Center are investigating a new treatment for glioblastoma, the deadliest form of brain cancer. Their paper, out this week in Cancer Discovery, shows how blocking a mechanism involved in cell metabolism and triggered by a cancer gene can reduce brain tumors.
Glioblastoma affects about 18,500 Americans each year, with less than More >
How Many Species are on Earth?
Sep 16th
For several years scientists have tried to estimate the number of species living on Earth. This is not an easy question to answer and multiple approaches have been developed to calculate how large Earth’s biodiversity is. All of the estimates obtained so far have a large prediction range, hundreds of thousands or even millions of species from the smallest estimates to the largest ones. On top of this shaming ignorance, our planet’s biodiversity is highly threatened. Solid evidence indicates that we are facing a massive extinction event, driven unfortunately by our own activities. The most recent evidence indicates that a More >
Biological Warfare
Sep 15th
Scientists at the Universities of Nottingham and Maastricht have engineered a strain of bacteria that may be able to fight cancer!
Clostridium sporogenes are anaerobic soil dwellers which cannot survive in the presence of oxygen. Researchers have genetically modified these bacteria so that they produce an enzyme that activates a cancer drug. It turns out that the centers of solid cancer tumors contain very little oxygen. Researchers hope to inject cancer patients’ tumors with the engineered Clostridium spores, which would not survive in the rest of the oxygen-rich body. After a tumor is infected with the Clostridium, a patient would also be More >
Made to Order
Sep 12th
Preimplantation genetic diagnosis (PGD) is a technique that allows scientists to screen embryos after fertilization through In Vitro Fertilization (IVF), to prevent the transmission of serious genetic diseases for couples who are at risk. It also can be used to screen the egg and sperm before fertilization occurs. Only unaffected embryos will be transferred to the uterus for implantation.
Image from Nature Reviews Genetics 3, 941-955 (December 2002)
While this technology offers the hope to increase the success of IVF, it does raise some concerns about choosing a child in order to meet the needs and desires of parents. While most cases seem to have More >
Genetic Insight into ADHD
Sep 9th
Attention-Deficit Hyperactive Disorder, more commonly known as ADHD is one of the most common neuropsychiatric disorders and is the most commonly diagnosed behavioral disorder of children. It affects about 7 percent of school-age children in the United States; affecting more boys than girls. This disorder is characterized by inattentiveness, hyperactivity and/or impulsivity that are out of the normal range for child development.
A diagnosis of ADHD is based on the persistence of several conditions for 6 or more months. Inattention is characterized by a child being easily distracted, missing details, forgetting things, and difficulty in focusing, among others. Hyperactivity can be More >
Rhythm of the Night
Sep 8th
Circadian rhythms, or cycles of activity during a 24 hour period, are highly conserved across species. While we have much to learn about these daily patterns of life, scientists have found an organism that may offer new insight.
The timing of this internal clock is related to the amount of exposure to light. How do circadian rhythms work in organisms that are not exposed to light? A Somalian cavefish, Phreatichthys andruzzii, is a blind species that has been living without light for approximately 1.4 to 2.6 million years!
Researchers compared the cave fish to zebrafish during exposures to 12 hour period of More >
