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The Center Voice

The Gay & Lesbian Community Center of Greater Fort Lauderdale, Inc.

June, 2000 (volume 7, number 6)



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PART ONE - EVOLUTION

Viruses are smaller than cells, and they do not perform all of the functions necessary to sustain life: ingestion of nutrients, expulsion of waste, reproduction, growth and development. Bacteria and viruses can both cause disease, however, bacteria are single celled organisms that, unlike viruses, can perform all the daily activities needed to maintain their lives.

Viruses, on the other hand, are tiny microscopic capsules which, for the most part, contain only genetic material. Some have DNA, others RNA. DNA is the genetic blueprint for life, and it is so important for life that it is only found in two places: encapsulated in viruses, and inside the nucleus of cells. The nucleus acts as a fortress which safely holds this vast library of our genetic codes. However, to be of any use to us, this information must get from the nucleus to the rest of the cell. Even though DNA holds these instructions inside the nucleus, it is too important to ever leave its fortress, because if it went outside and got lost, this would be catastrophic and fatal for the cell. Instead, to prevent the loss of any genetic material, an expendable copy is made of the DNA instructions. This copy is called RNA, and it, rather than the DNA, travels outside the nucleus to other parts of the cell to provide instructions for life sustaining tasks.

Every cell in our body contains in its nucleus the entire genetic code for all the bodily functions of our life. However, each cell only uses a small part of that vast library: the portions which tell it how to carry out its own unique life sustaining duties. For example, liver cells only read the part of the genetic code that tells them how to do liver things, while brain cells only follow instructions from the brain portion of this immense library. At least that is how it is supposed to work when we are healthy. This highly disciplined practice of cells only borrowing books from those parts of the library that pertain to their role in sustaining life is a product of evolution.

Millions upon millions of years ago, before any plants or animals existed, life on this planet consisted mostly of simple, single celled organisms. Back then, each cell had the ability to perform all the functions of life independently, without the help of any other cell. The genetic code contained inside each nucleus had all the instructions they needed to live, grow and produce offsprings. For eons this worked fine and dandy, with single celled organisms living, dying and reproducing independent from one another. Somewhere along the line, however, things changed.

Between the era of strictly single celled organisms and today, cells began to live together and work with one another, no longer floating aimlessly about all alone. They found it beneficial to organize in ways which improved their survival and procreation abilities. They started with loose associations, then they began to merge, first into two celled, then three, four and more celled organisms. Over the eons, as the number of cells in each new species increased, so did the complex abilities of new generations and the amount of genetic code needed to keep them alive. In addition, as species became more and more divergent from one another, so did the contents of their genetic storehouses. The DNA library for an albatross, though having similar instructions, is significantly different from that of a cougar, which in turn is not the same as the genetic codes for people.






The Center Voice

The Gay & Lesbian Community Center of Greater Fort Lauderdale, Inc.

July, 2000 (volume 7, number 7)



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PART TWO - CONSERVATION

Each species of life has different overall needs and ways of living, so each keeps a different overall genetic library. Yet, within any multi-celled organism, the DNA code, which regulates and defines life, is too crucial to either be kept in one place or be divided up into parts that are held only by the cells that use them. If there were just one copy, what would happen if it were accidentally lost, damaged, or completely destroyed? If, instead, the library was broken apart and distributed amongst individual cells, what would happen if something went wrong in the complex dividing process and cells got incomplete or wrong parts of the code? To avoid these and other similar disasters from occurring, every cell inside of us contains more than just the genetic data it needs for its particular tasks. Each has a complete copy of the entire DNA record used by it and every other cell in our body. In this way all cells are certain to have access to the DNA they need to keep us alive, since each has its own complete copy of all the DNA we possess.

Evolution has driven life onward, from the age of single cell organisms to what we are today. Along the way, countless species have come and gone, each with its own unique way of living, and each with its own individual genetic library. In this process, some earlier species have acted as predecessors to later ones, giving the better parts of their older codes to the newer species' library. This passing on of genetic data allows evolution to pick and choose the best of its blueprints for successive generations. However, not all species pass their codes on. Some become extinct and disappear without any successors, and with them go their vast libraries of genetic information. With no one to receive the volumes of experience catalogued in their DNA, billions of evolutionary years are lost as these blueprints are trapped inside a dead end species. Yet, just as nature has had to be sure that all cells of an organism contain a complete genetic library, nature also provides a way to exchange genetic data between unrelated living organisms. In this way, should a particular species become extinct without a DNA heir, bits and pieces of their code might at least survive within the library of some other lineage. Thus, nature provides an opportunity for genetic data to be conserved beyond a species in case that species should become extinct. This attempt to share the evolutionary blueprint of life comes in the form of a genetic interlibrary loan service called viruses.

Viruses are like little envelopes of genetic letters which can be mailed back and forth between single cells and entire organisms. They may contain either DNA or RNA (HIV contains RNA) and their goal is to transport genetic information from the nuclear library of one cell (the sender cell) and deposit it in the nuclear library of another cell (the receiver cell).

Unfortunately, the viral postal service is not a highly efficient one, and it does not care if the address of the receiving cell is next door to the cell it is sent from, or even in the same organism as that of the sender cell. Amazingly, and most importantly, viruses do not even care if the receiving cell is of the same specie or function as the sender cell, and may take genetic code from a kidney cell of a goose and try to place it in a leg muscle cell of a cat. Actually, most of these genetic messengers never reach a receiver cell and just travel aimlessly about once they leave the sender cell until they just fall apart. Even if they do manage to find their way to a receptive cell in whose nucleus they can deposit their genetic content, in the process of entering the receiver cell they are often destroyed.






The Center Voice

The Gay & Lesbian Community Center of Greater Fort Lauderdale, Inc.

August, 2000 (volume 8, number 6)



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PART THREE - REPRODUCTION

At best, one virus can only deliver its contents to just one cell, and most never get that far. Yet, every so often one of these envelopes reaches its destination and gets to place its contents inside the nucleus of a cell. If the virus contains DNA, then its contents are placed right up on the genetic shelf inside the nucleus, ready to be read at a moment's notice. If, however, the virus contains RNA, then it also carries a special chemical, called an enzyme, which will convert the RNA data to DNA before entering the nuclear stronghold (in HIV, this enzyme is called reverse transcriptase). Whether they contain DNA or RNA, a virus' only goal is to deposit its genetic material in the DNA library of a cell. In this way an organism can contain more than just the genetic materials necessary for its own species survival. Viruses share data between the living libraries of different species, thus providing a way to prevent the loss of all the genetic codes within a particular species should it become extinct.

Viruses are natures little conservationists who attempt to guarantee that millions of years of evolution needed to produce DNA will not be for naught, should the individuals who carry and use that DNA not survive the evolutionary process. Once lost, the circumstances that allowed the creation of a particular piece of DNA may never happen again. However, it is impossible to say how useful a particular code may be in the future, so it is better to try and save DNA codes rather than allow them to become extinct. Who knows, we may have the blueprints for the teeth of a brontosaurus or the tusks of a woolly mammoth floating amongst our own genetic instructions. One day we may even find a use for them. For now, they just sit dormant inside of us. Since we cannot tell what their past or future applications might be, science labels them as nonsense or garbage codes. Nature, on the other hand, is waiting to see if evolution has any further need for the information they contain. Only time will tell, but nature knows that once created it is much easier to hold onto a code, even if kept locked deep in a library basement, than to recreate it all over again. Therefore, viruses constantly bring us new genetic information to add to our ever expanding warehouses. Though we may not use them in our lifetime, there is no telling what value these codes might be to future generations.

The job of the virus is so important that it carries more than just seemingly indiscriminate blobs of genetic data. Though a lot of the blueprints inside a virus may appear to be nonsense whose past or present applications are not understood, the viral package also includes key instructions for creating more viruses. Along with everything else these little interlibrary loaners bring to a cell, they also drop off their own blueprints in the hope that the cell will read them and make more of these genetic couriers. Remember, viruses, unlike cells, cannot carry out the basic functions of life. They do not appear to ingest any nutrients in their travels, neither do they produce any waste products, and they cannot reproduce themselves. Therefore, they depend upon the cell where they deposit their data to do their reproduction for them. It is a life imitating cycle in which new genetic material, directly through DNA or indirectly through RNA, is placed inside of a cell's nuclear library where it waits to be read. If the right part of that data is used, then the cell, along with all its other functions will be instructed to make more viruses which, in turn, leave the cell and spread more genetic news to other libraries.






The Center Voice

The Gay & Lesbian Community Center of Greater Fort Lauderdale, Inc.

September, 2000 (volume 7, number 9)



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PART FOUR - CURIOSITY

For the most part, viruses do not carry much new information that we do not already have, and the data they do have is most often of little use or importance to us. We have millions of these tiny messengers floating inside of us every day, with most wandering harmlessly about, never reaching a library in which to make their delivery. Even when a virus does manage to find a new home for its genetic cargo, viral reproduction blueprints and all, these codes often end up on dusty shelves and are never taken down to be read. On the rare chance that they are read, the instructions they contain are likely to most often be illegible to the cell and, thus, they are placed back on the shelf without ever being used. However, every so often one of these viral interlibrary loan deposits is taken off the shelf and found to contain legible instructions which the cell can carry out. Cells are curious things, and once they find a legible blueprint in their nuclear library, they tend to do, or at least try to do, what it tells them. Yet, if the cell is not careful, following certain blueprints can be disastrous.

It is said that curiosity can kill a cat, and the same may be said of cells which read the wrong genetic information. Normally, a cell will read from its nuclear library, only those parts it needs to perform its unique life sustaining duties. Though all cells have a complete set of instructions to do everything its organism needs to survive, heart cells have no use making urine as do kidney cells, and stomach cells do not try to breath for us the same as do lung cells. They tend to only read the things they need for their individual role in maintaining life. Sometimes, however, things go wrong. For some unknown reason, maybe by accident or because cells get bored of reading the same old thing over and over, every now and then they open a new book and follow new orders rather than their usual DNA instructions. Under these circumstances, cells begin spending time on tasks they would not usually perform. Sometimes these activities are very minor and use up little of the cells resources. However, if these instructions are the blueprints for making more viruses, then a cell may become a baby factory, devoting more and more of its energy to manufacturing these genetic messengers. This can be fatal for a cell, as viral production can start to supercede normal cellular activities which support our life. If too much time is spent pumping out these tiny genetic envelopes, then the cell will not have the energy to do its regular job and it will die. If enough cells in our body are affected by this same process, then they may all die, and our health will be at risk

There is nothing moral or immoral about a virus. In the end, conservation, like everything else in life, is a double edged sword. It is designed to safeguard and protect us, yet it can, at times, backfire against and cause harm to us. The need for viruses is indisputable. They are nature’s agents of genetic conservation, and they play a crucial role in the evolutionary integrity of all life forms. Even modern science recognizes their importance in carrying genetic information, as viruses are used to deliver gene therapy today. However, viruses can, at certain times, also lead to the unintentional downfall of the very organisms they are designed to protect. Viruses are not designed to be bad, they are designed to serve the evolutionary process of life. Yet, in that design lays the potential for harm, and this is why bad viruses happen to good people.





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