Well what do I mean by lasting changes? Research has shown that depending on what your mother eats may influence your genes and health in the long run. The gene agouti is found in humans and mice. The agouti/melanocortin system is an important regulator of body weight homeostasis. Mouse studies have shown that when the agouti gene is not methylated the result is obese yellow coated mice which may be at risk for cancer and diabetes. When the gene is methylated mice are brown, of normal weight and size. The only difference between the two types of mice is the methylation control on the agouti gene. In parallel experiments were carried out where yellow female mice were fed a methyl enriched diet; the offspring grew to be normal weight, size and were brown in color and remained so for the rest of their adulthood. This study identified that an individual’s wellbeing is not only determined by what they eat but also what their parents ate.

References
Nutrition and the epigenome. Retrieved February 8, 2012, from http://learn.genetics.utah.edu/content/epigenetics/nutrition/

When we think of a detective the first thing that comes to mind is an investigator, either a member of a police agency or a private entity.  However there are unique detectives within the multifaceted arena of medicine.  All though we might already think of most doctors as detectives there are special doctors, units, working at the National Institute of Health’s (NIH) undiagnosed disease program.  Doctors such as William A. Gahl at the NIH are disease detectives that try to elucidate the causes and genetic basis involved in the hundreds of unsolved and mysterious diseases that arise each year.  Dr. Gahl who was interviewed for an article in scientific American explained that his group has accepted 400 out of 1700 special cases of unsolved disease.  The selection process of these cases is tough, determining which cases are new diseases and if there is a possibility of determining the genetic and biochemical basis of the disease.   As each case is worked mutations are identified that are associated with each disease.  But Dr. Gahl States that this is only the beginning of the puzzle.  The challenge becomes to identify the genetics with the pathology.

Dr. Gahls’ group has been working on a case in which a patient has endured pain for approximately twenty years and muscles of their legs have turned as hard as bricks limiting mobility.  It was determined that the patient had a rare condition in which their blood vessels bore a thick coat of calcium that restricted blood flow.  One of the first steps taken in the study was to examine the parents of the patient.  The parents after examination were healthy, which lead the group to believe that the patients’ disposition might be due to a recessive mutation.  Meaning that each parent had only one copy of a unique mutation but upon having children probability lead to the patient receiving two copies of the mutation.  After an in depth study Dr. Gahls’ group identified the location of the mutation and the error prone gene associated.  The gene that was identified is NT5E.  NT5E is involved in the production of the nucleoside adenosine (which is involved in a number of biochemical processes).  To examine this gene closely doctors cultured the patients skin cells and inserted the normal gene of NT5E and even introduced adenosine alone into the cells and miraculously they observed a reduction in calcification.  Through this analysis a better understanding of adenosine in the regulation of calcium has been brought to light.  However Dr. Gahl explains that there are a number of reasons why patients cannot just receive adenosine, but there is a class of osteoporosis drugs that pose as good candidates for treatment and they are waiting to see how these drugs perform.

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For most of the year, deciduous trees are green because of chlorophyll in the chloroplasts.  This pigment helps harness energy from the sun to fuel photosynthesis, or food production.  In the fall, days become shorter and sunlight more sparse, so plants begin to prepare for the winter – a period during which they rely on stored nutrients.   Nutrients are stored and superfluous leaves are shed , but before that, the chlorophyll begins to disappear, revealing other pigments such as yellow and orange that weren’t visible before.  Sometimes during this process, new pigments (such as reds) are produced as well.

This is controlled by up to 35 genes that can turn on and off in response to the reduction of sunlight hours.  It is a great example of the interaction between an organism’s DNA and its environment, a phenomenon many people are unaware of.  The traits and characteristics of all living things are the result of a combination of its genetic makeup and its physical and chemical surroundings.  To learn more about this type of interaction, go to chapter 35, “DNA responds to signals from outside the cell.”

Well, it could be your family and it could be your environment. Studies have shown that addictions run in families. In fact, if a parent has an addiction, the child is 4 to 8 times more likely to have an addiction as well. It doesn’t necessarily have to be the same addiction, but an addiction nonetheless. Those with other family members with an addiction are more susceptible to the disease, but that also doesn’t mean that the disease is inevitable.

Saying that addiction runs in the family would speculate a possible genetic component. In fact, researchers are currently trying to link addiction to a cluster of genes in the human genome. Scientists are looking for “addiction genes” that are biologically different from others that might make someone prone to addiction. It also might affect the severity of withdrawals.

For example, in humans, a candidate gene for addiction includes the A1 allele of dopamine receptor gene DRD2 which is common in those with alcohol and cocaine addictions. Also, non-smokers are more likely to carry a protective gene, CYP2A6, which causes them to feel more nausea and dizziness from smoking.

Mice have been a model for studies on human addiction because the reward pathway functions in mice are very similar to those in the human brain.

Mice bred to lack serotonin receptor gene Htr1b are more attracted to cocaine and alcohol. Those with low levels of neuropeptide Y drink more alcohol while those with higher levels tend to abstain from alcohol.

It mainly all comes down to the reward pathway in our brains. The reward pathway is in the center of our brain and connects to other areas such as those controlling memory and behavior. It’s responsible for driving our feelings of motivation, rewards and behavior. The main job of the pathway is to make us feel good when we engage in behaviors essential to survival such as eating and drinking. Places in the brain gather information about what’s happening outside of our body and then strengthen circuits within the brain that control desirable behavior.

For instance, say you’re thirsty and someone hands you a cold water bottle. The brain will tell you that there’s cold water in front of you. Stored in your brain is a memory that says “if you drink that water, you won’t be thirsty anymore and you’ll feel good!” So you’ll drink the water. While drinking, you’re 5 senses will send a single to your brain about drinking the water. The brain, in response will release dopamine, giving you a jolt of pleasure which is your instant reward. The reward pathway will make you repeat the behavior for the same dopamine reward, like a dog doing a trick for a dog biscuit. The wiring in your brain for that particular activity has been strengthened.

Despite the genetic link, it’s not all due to our DNA makeup. Essentially, addiction is the combination of the interaction of several genes (not just a single gene) with social and environmental factors. Also, just because someone has all that’s necessary for an addiction doesn’t mean they’ll have an addiction problem. For example, I know I have an addictive personality but I look for other ways to expel or sedate the addiction and to put that addictive capability to better use.

Researchers have been searching for ways to treat and prevent addictions. One way is the identification of genes. The genes can become “drug targets,” in which researchers can work to modify the gene product’s activity resulting in stabilizing or reversing pathways to restore the brain to proper function.

Earlier this year, researchers at UT Southwestern Medical Center have a new hypothesis. They hope that by increasing a process known as neurogenesis it might prevent or treat addiction. Neurogenesis is a normally occurring process of making nerve cells in the brain. In previous studies, blocking neurogenesis had increased a rodent’s vulnerability for cocaine addiction and relapse. They hope that by stimulating the increase of neurogenesis, it might combat addiction. Another application is to use this increased neurogenesis in situations where a patient is required to use a potentially addicted medication such as Vicodin, a severe pain killer with a high addiction rate. Perhaps this treatment may be used in those who have quit their addiction in order to prevent a relapse.

Recently, new research focusing on microRNA (miRNA) and gene expression might also have a potential effect on the fight with addiction. miRNAs are used in gene expression regulation and gene silencing. They bind to complementary mRNA strands and prevent translation to a protein. Raising the levels of miR-212, an miRNA, in the brains of cocaine-using rats have caused the rodents to take in less of the drug. Completely blocking the miRNA, and allowing full gene expression, increased the drug use. This would suggest a new drug target- a medication to raise miR-212 levels or at least creating something to mimic the miRNA’s function. Liked to miR-212 is an increase in the protein CREB. CREB holds promise in fighting drug addiction by decreasing the reward response, sometimes actually creating an aversion to it all together. The only obstacle with CREB drug targets is the regulation of it. The level cannot become too low (where the rewards are increased) because it can lead to addiction and anxiety, but it cannot become too high (where nothing is rewarding) which can lead to depression. This study has only been done with cocaine and is currently under investigation for the applications in nicotine and alcohol addictions.

Someday, possibly, there will be ways for those suffering from addictions, whether they be chemical addictions, which is heavily mentioned here, or an addiction to more physical things to overcome that addiction and lead healthier lives.

"Eye Colors in Man," from The Trait Book, ERO Bulletin No. 6, by Charles B. Davenport, 1912 (Archive Image #1913)

Davenport and other eugenicists oversimplified eye-color inheritance early in the last century, and we have since come to discover that several genes determine eye color.

Recently, a group in the Netherlands has taken our understanding a step further by using high resolution imaging and analysis of nearly 6,000 individuals to identify eye-color using a color spectrum, while previous studies utilized color categories (blue, green, brown). The researchers photographed the subjects’ eyes and identified the color on a spectrum that evaluated hue and saturation. Then they conducted a genome-wide association study and found three new regions on chromosomes 1, 17, and 21 that contribute to eye-color-variation, adding to the seven already known genes. They claim that using their prediction model, 50% of eye-color variation can now be explained. Davenport wouldn’t believe his eyes!

Read more about the study here: http://blogs.nature.com/news/thegreatbeyond/2010/05/suspect_has_hazel_eyes_with_h.html

One very amazing example of this is the Widowbirds that live in the grasslands of southern and eastern Africa.  During the non-mating season, the males and females look very similar to one another.  Once breeding season begins, the males molt and produce long black feathers, some that can be up to half a meter in length.  Studies have been done where feathers have been glued on to some males, and females chose these males over others with shorter tails.  You also have to wonder why the tails don’t get even longer.  That even though females desire very long tails, if they get too long, they could hinder the flight of the birds, which would decrease their fitness.

Other examples that might be more familiar to you are the elaborate feathers of male peacocks, and the beautiful plumage of male birds.

In contrast, there was a an effort to prevent hereditary blindness within the eugenics movement. Its proponents collected pedigrees, drafted legislation to prevent marriage of blind individuals, and surveyed ophthalmologists to assess causes of blindness and the cost to society to provide for the blind in specialized homes and schools. Their intent was to eliminate blindness in future generations. However, this was eugenics because affected individuals would not have been allowed to decide for themselves if the trait was undesirable, or what steps to take eliminate it.

Pedigree of a family with blindness

Explore the Eugenics Archive, especially the “Hereditary Disorders” topic, for many examples of how eugenicists viewed inherited diseases.

For example, when someone has hemophilia (a blood clotting disorder), there is a mutation in a gene that normally tells our cells how to make proteins called clotting factors. The mutation prevents a specific clotting factor from being produced, and as a result, the individual carrying the mutation has the disease and the blood doesn’t clot as it should after an injury. It’s a gene we all have, but if someone has hemophilia, the gene just isn’t working properly.

Another common misunderstanding is that if a disease is genetic, it is always inherited. It is true that many disease-causing mutations are inherited. Sometimes though, the mutations that cause genetic diseases develop over time, after we are born. Many of the mutations associated with the development of cancer, accumulate in our cells as we age, and aren’t inherited. These diseases are genetic, because they are caused by mutations in genes, but they aren’t passed from parent to offspring. Less than 10% of all cancers are inherited!

It’s no wonder that not only children, but adults too, are misinformed. These types of incorrect phrases and misinterpretations are printed all the time in magazine and newspapers. So where do you go for correct information? To learn more about the genetics of cancer, go to: www.insidecancer.org. To learn more about basic laws of inheritance, use DNA From the Beginning (www.dnaftb.org). To learn more about the inheritance of mutations that cause disease, go to: http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gnd, the Online Mendelian Inheritance in Men (OMIM) database.

Progeria is a very rare, genetic disorder that afflicts roughly one in 5 million people. It is caused by a mutation in the LaminA gene on chromosome 1. The most striking symptom of Progeria-afflicted children is that they age rapidly. They frequently succumb to coronary artery disease before they reach 20 years of age.

Directed by R Balakrishnan the Indian movie company AB Corp Ltd. has released the movie “Paa”. The picture’s protagonist is a 13-year old boy afflicted with progeria – and is being played by an actor who is actually in his 60s. AB Corp Ltd. proclaims that Paa is not a movie about the disease Progeria, but about “how special children can fill your life with special brightness.”

Read more: about Progeria at the Progeria Research Foundation; about living with serious genetic disorders at the DNALC’s Your Genes, Your Health site.

Demonstrations with this wheel have led to some very interesting student responses and questions.  I have been accosted in the museum by students who believe that the wheel has actually predicted what gender their children will be, and even how many they will have!  This has led me to beat them to the punch during my demonstration, by explaining that the wheel is not a predictor of the future!

I have also been asked by concerned 10-year-olds, how much DNA their parents could possibly have left over after having 4 children? This one is a favorite of mine. When you really think about it, that thought makes perfect sense. Unless you’ve learned about meiosis and sex cells, how would you know that there are special cells, each containing extra copies of the genetic information to be passed on to children? In avoidance of these “uncomfortable” topics, some children are somewhat mislead when they begin learning about inheritance.

When I work with 5^th graders and discussions of 46 chromosomes per cell come up, I always add that some cells have no DNA (mature red blood cells) and some cells have only 23 chromosomes.  Inevitably, someone will ask why, and if they don’t I do! There are special cells that are used for reproduction, and when two of these cells unite, from a mother and a father, a full set of chromosomes is created. Covering this basic concept without the burden of meiosis, is perfectly suitable for 10-year-olds, and eliminates confusion.o