Although many diagnosed with diabetes have the disease somewhere in their family medical history, diabetes is not a disease that is inherited in any simple pattern.

First of all, Type 1 and Type 2 diabetes do not have the same causes. However, there are two factors that are involved in both: there must be an inherent predisposition for the disease and there must be a trigger for it.

Proof that genes alone are not enough to get diabetes can be found in the case of identical twins. Identical twins have identical genes, yet in cases where one twin is diagnosed with Type 1 diabetes there is only a 50% chance that the other twin will also develop the Type 1 diabetes. If the diagnosis is Type 2 diabetes, then the risk goes to 3 out of four for chance. A mixture of nature and environmental factors make it impossible to determine who will get diabetes and who will not.

Type 1 Diabetes

When it comes to Type 1 diabetes, people generally need to inherit risk factors from both sides of their family. These risk factors are very prevalent in Caucasian segments of the population. Still, even those who are at risk do not always get diabetes, prodding researchers to dig deeper into what possible environmental triggers there are that set off the disease.

Type 1 diabetes is known to occur more often in winter than in summer and therefore has researchers believing that cold weather is a possible trigger. Viruses are also suspected as a trigger as well as other auto-immune diseases. (Diseases in which the immune system attacks the body's tissues.)

Type 2 Diabetes

Of the two types of diabetes, Type 2 has the stronger genetic base but depends a great deal more on environmental factors. The genetic predisposition for Type 2 diabetes mixed with those living in a Western lifestyle is an infamous cocktail for developing this disease. As is such with the great majority of the Western diet and lifestyle, too much fat and refined carbohydrates and not enough fiber coupled with inactivity has birthed this disease into epidemic proportions. As obesity rises, so do reports of diabetes. In comparison, those living in areas of the world that are not Westernized do not develop Type 2 diabetes despite their high genetic risk.

Gestational Diabetes

Gestational diabetes, diabetes that develops during pregnancy, has no clear genetic or environmental triggers. Although women who develop the disease are more likely to have a family history of diabetes, it is unclear what other non-genetic factors play a role. Women who put off having children until their later years and women who are overweight seem to be the most common groups to be diagnosed but this is not always the case.

So what is the conclusion here? You can have the genetic risk, environment, and the lifestyle triggers, and still not develop diabetes. The other side is also true. Diabetes can develop without many of the triggers.

The only thing that we as a human race can do is limit the triggers for diabetes as much as we can. Eat healthy, exercise regularly, keep our weight under control and hope that our genes are in our favor.

It seems that some people are destined to be skinny. They have never known being fat, and they make being thin look easy. Others of us are in the opposite situation. It is a struggle to lose weight, and being thin seems impossible. Could it be that our genes have something to do with it? As it turns out, there are several genes that play a role in obesity. Defects in some of these genes cause certain syndromes to develop. Not everything is known about the genetics of obesity, but our knowledge is expanding.

A part of the brain called the hypothalamus controls several functions of the body. One of these is the regulation of the sense of hunger. There is an interplay between various chemical messengers and the hypothalamus. This interplay is called the hypothalamic leptin-melanocortin system. Our fat cells make a signal called leptin. The more fat we have, the more leptin is produced. It binds to the leptin receptor in the hypothalamus. The hypothalamus senses a minimal amount of leptin which tells the brain that the body has at least the required amount of fat to function. Once the receptor is activated, a protein called proopiomelanocortin (POMC) is made. POMC is then cut into smaller parts by enzymes. One of these enzymes is proenzyme convertase 1 (PC-1). One of the smaller proteins produced by PC-1 is called alpha-MSH which binds another receptor in the hypothalamus called MC4R. Once MC4R is turned on, it triggers some intracellular signals that end up telling your brain that you are not as hungry. Got all that?! Check out the link at the end of this article and go to the "Genetics" tab. On the "leptin" page, there is a diagram that explains it.

A defect in the genes for any of the signals, enzymes, and receptors mentioned above can lead to an increased appetite. The most common of these mutations is a defect in MC4R. However, it is not the most severe, and some people with a defective MC4R gene are still thin. Mutations in other genes cause a voracious appetite in very young children, and they are nearly destined to eat far more than their bodies will ever need. In addition to becoming very obese, associated problems can include: small ovaries and testicles, thyroid dysfunction, decreased immunity, and low functioning adrenal glands. Fortunately, these more severe conditions are rare with only a handful of known cases. There are treatments for a few, like replacing leptin with shots. For others, like MC4R, there are to treatments.

A few genes that aid in the development of the hypothalamus are also associated with obesity. The SIM1 gene encodes signals that come from the MC4R receptor. One case of a young girl with a SIM1 mutation was obese and also tall. In addition to development of the hypothalamus, the tropomysin-related kinase B (TrkB) receptor and the chemical signal called brain-derived neutrotrophic factor (BDNF) play roles in memory, behavior, and intellect. Defects in either of these two can cause obesity and memory problems.

In the reward center of the brain, dopamine is released when we eat food. People who have mutations in a stretch of DNA called TaqIA have fewer dopamine receptors and thus need to eat more to feel the same sense of reward. This lends weight to the fact that some people may literally be addicted to food, and the sweeter the food, the stronger the addiction.

There are also several genetic syndromes associated with obesity that involve more than one gene. They are too complex for this article, but here is a list of some of them: Prader-Willi, Bardet-Biedl, Ahlstrom, Cohen, and Carpenter syndromes.

Humans are running out of fresh water, and that seems kind of interesting considering two thirds of our planet is water on the surface. Still saltwater is undrinkable for humans and so, we can only drink fresh water, and we must have it to survive. This means we need more desalination plants to keep up with our demand. Not only to drink but also for agriculture, livestock, and cleaning, cooking, and hygiene.

As we learn more and more about the human genome we will be able to modify humans in such a way that they may not retain as much water or need as much water to survive. There are many animal species that do not require very much water and they have evolved and adapted to live in harsh environments such as desert regions, or live high up in the mountains where there is only water part of the year.

With 6.8 billion people on the planet water is a very serious issue, and we do have a global water crisis, which is getting bigger; along with our population growth and our needs. Most people decry the genetic modification of much of anything, but in the future it is something we're going to have to look at.

We may be genetically modifying humans to do all sorts of things such as long-term space travel, increased intelligence, and to prevent aging. So if we're going to do all that we may as well also genetically modify people that don't need to drink as much water and can survive on less. That only makes sense. Please consider all this.

Genetic engineering today is no longer a new term for the world. Every day in the newspapers, televisions, magazines the new inventions of genetic engineering are noticed. Genetic engineering may be described as the practice that manipulates organism's genes in order to produce a desired outcome. Other techniques that fall under this category are: recombinant DNA technology, genetic modification (GM) and gene splicing.

HISTORY

The roots of genetic engineering are connected to the ancient times. The Bible also throws some light on genetic engineering where selective breeding has been mentioned. Modern genetic engineering began in 1973 when Herbert Boyer and Stanley Cohen used enzymes to cut a bacteria plasmid and inserted another strand of DNA in the gap created. Both bits of DNA were taken from the same type of bacteria. This step became the milestone in the history of genetic engineering. Recently in 1990, a young child with an extremely poor immune system received genetic therapy in which some of her white blood cells were genetically manipulated and re-introduced into her bloodstream so that her immune system may work properly.

PROMISE

Genetic engineers hope that with enough knowledge and experimentation, it will be possible in the future to create "made-to-order" organisms. This will lead to new innovations, possibly including custom bacteria to clean up chemical spills, or fruit trees that bear different kinds of fruit in different seasons. In this way new type of organisms as well as plants can be developed.

PROCEDURE

Genetic engineering requires three elements: the gene to be transferred, a host cell into which the gene is inserted, and a vector to bring about the transfer. First of all, the necessary genes to be manipulated have to be 'isolated' from the main DNA helix. Then, the genes are 'inserted' into a transfer medium such as the plasmid. Third, the transfer medium (i.e., plasmid) is inserted into the organism intended to be modified. Next step is the element transformation whereby several different methods including DNA guns, bacterial transformation, and viral insertion can be used to apply the transfer medium to the new organism. Finally, a stage of separation occurs, where the genetically modified organism (GMO) is isolated from other organisms which have not been successfully modified.

APPLICATIONS

Genetic engineering has affected every field of life whether it is agriculture, food and processing industry, other commercial industries etc. we will discuss them one by one.

1. Agriculture Applications

With the help of genetic engineering it would be possible to prepare clones of genetically manipulated plants and animals of agricultural importance having desirable characteristics. This would increase the nutritive value of plant and animal food. Genetic engineering could lead to the development of plants that would fix nitrogen directly from the atmosphere, rather than from fertilizers which are expensive. Creation of nitrogen fixing bacteria which can live in the roots of crop plants would make fertilization of fields unnecessary. Production of such self fertilizing food crops could bring about a new green revolution. Genetic engineering could create microorganisms which could be used for biological control of harmful pathogens, insect pests, etc.

2. Environmental Applications

Genetically modified microorganisms could be used for degradation of wastes, in sewage, oil spills, etc. Scientists of the General Electric Laboratories of New York have added plasmids to create strains of Pseudomonas that can break down a variety of hydrocarbons and is now used to clear oil spills. It can degrade 60% of the crude oil, while the four parents from which it was derived break down only a few compounds.

3. Industrial Applications

The industrial applications of recombinant DNA technology include the synthesis of substances of commercial importance in industry and pharmacy, improvement of existing fermentation processes, and the production of proteins from wastes.

4. Medicinal Applications

Among the medical applications of genetic engineering are the production of hormones, vaccines, interferon; enzymes, antibodies, antibiotics and vitamins, and in gene therapy for some hereditary diseases.

Hormones

The hormone insulin is currently produced commercially by extraction from the pancreas of cows and pigs. About 5% of the patients, however, suffer from allergic reactions to animal-produced insulin because of its slight difference in structure from human insulin. Human insulin genes have been implanted in bacteria which, therefore, become capable of synthesizing insulin. Bacterial insulin is identical to human insulin, since it is coded by human genes.

Vaccines

Injecting an animal with an inactivated virus stimulates it into making antibodies against viral proteins. These antibodies protect the animal against infection by the same virus by binding to the virus. Phagocytic cells then remove the virus. Vaccines are manufactured by growing the disease-producing organism in large amounts. This process is often dangerous or impossible. Moreover, there are difficulties in making the vaccine harmless.

Interferon

Interferons are virus induced proteins produced by cells infected with viruses. They appear to be the body's first line of defence against viruses. The interferon response is much quicker than the antibody response. Interferons are anti-viral in action. One type of interferon can act. Against many different viruses, i.e. it is not virus specific. It is, however, species specific. Interferon from one organism does not give protection against viruses to cells of another organism. Interferon provides natural defence against such viral diseases as hepatitis and influenza. It also appears to be effective against certain types of cancer, especially cancer of the breast and lymph nodes. Natural interferon is collected from human blood cells and other tissues. It is produced in very small quantities.

Enzymes

The enzyme urokinase, which is used to dissolve blood clots, has been produced by genetically engineered microorganisms.

Antibodies

One of the aims of genetic engineering is the production of hybridomas. These are long lived cells that can produce antibodies for use against disease.

5. Gene therapy for treating hereditary diseases

The earlier gene transplantation experiments were concerned with trans¬planting genes in vitro into isolated cells or into bacteria. Gene transplantation experiments have now been extended to living animals.

6. In Understanding of Biological Processes

Genetic engineering techniques have been used for acquiring basic knowledge about - biological processes like gene structure and expression, chromosome mapping, cell differentiation and the integration of viral genomes. This could lead to a better under¬standing of the genetics of plants and animals, and ultimately of humans.

7. Human Applications

One of the most exciting potential applications of genetic engineering involves the treatment of genetic disorders. Medical scientists now know of about 3,000 disorders that arise because of errors in an individual's DNA. Conditions such as sickle-cell anemia, Tay-Sachs disease, Duchenne muscular dystrophy, Huntington's chorea, cystic fibrosis, and Lesch-Nyhan syndrome are the result of the loss, mistaken insertion, or change of a single nitrogen base in a DNA molecule. Genetic engineering makes it possible for scientists to provide individuals who lack a certain gene with correct copies of that gene. The proposal for human cloning are still waiting to come on floor. Genetic engineering has benefited the couples who are infertile.

Safe guards of genetic engineering

The general safeguards for recombinant DNA research are outlined below:

1. Genes coding for the synthesis of toxins or antibiotics should not be introduced into bacteria without proper precautions
2. Genes of animals, animal viruses or tumour viruses should also not be introduced into bacteria without proper precautions.

3. Laboratory facilities should be equipped to reduce the' possibility' of escape of pathogenic microorganism by using microbial safety cabinets, hoods, negative pressure laboratories, special traps on drains lines and vacuum lines.
4. Use of microorganisms occupying special ecological niches such as hot springs and salt water should be encourage If such organisms escape they will not be able to survive.
5. Use of non-conjugative plasmids as plasmid cloning vectors is recommended as such plasmids are unable, to, promote their own transfer by conjugation.

Dangers of genetic engineering

Recombinant DNA research involves potential dangers. Genetic engineering could create dangerous new forms of life, either accidentally or deliberately. A host microorganism may acquire harmful characteristics as a result of insertion of foreign genes. If disease-carrying microorganisms formed as a result of genetic manipulation escaped from laboratories, they could cause a variety of diseases. For example, Streptococcus, a bacterium causing rheumatic fever, scarlet fever, strep throat and kidney disease, never acquired penicillin resistance in nature. If a plasmid carrying a gene for penicillin resistance is introduced into Streptococcus it would confer penicillin resistance on the bacterium. Penicillin would now become ineffective against the resistant organism.