Over the past several years Genetics has become a leading link to understanding how our
body works. By mapping out deoxyribonucleic acid, or DNA, scientists plan to find cures
for various diseases, develop better, more efficient drugs, grow new organs, evaluate
environment hazards, and eventually build a human being.
Inside of every single cell in our bodies there are 46 chromosomes that are made
up of DNA. Half of your chromosomes are inherited from each parent, DNA is strung
along the chromosomes. DNA is the living instructional manual found in all living
organisms. The building block letters of DNA are Adenine, (A), Thymine, (T), Cytosine,
(C), and Guanine, (G). These are repeated over and over again about 3 billion times in our
body alone. DNA can be subdivided into genes, with each gene carrying the information
on how to produce a unique protein. Each gene consists of three of the building blocks
placed together. Along the stretches of DNA, genes tend to occur in clusters, like cities
separated by vast emptiness. When the DNA is collected all together you have a genome.
In the past scientists believed that there was more than 100,000 genes in the
human genome, but recent studies by Celera Genomics and many other scientist based
teams, have found that the number
information has made some biologists ecstatic and has wounded the pride of others.
“There are many people who are bothered by the fact that they don’t seem to have (many)
more than twice as many genes as a fruit fly,” said Eric Lander, director of the Whitehead
Institute Center for Genome Research. “It seems to be some kind of affront to human
dignity.” The 30,000 genes in our body compared to the 13,600 in the fruit fly does seem
to raise questions about why we have the abilities to do so much more when we don’t
have that many more genes in our genome. Even though all creatures share the same DNA
code, some people still believe that there is a step-change between the rest of nature and
humans that separates us from them.
The Human Genome Project, starting in the 1980’s, is a research program
designed to construct a detailed genetic and physical map of the human genome,
determine the complete sequence of human DNA, localize 30,000 to 35,000 genes, and
perform similar analysis on the genomes of several other organisms.
Every species has its own genome. Every individual animal within a species has its
very own specific genome. Unless you are an identical twin your genome is different from
everyone on earth – and from everyone who has ever lived. Even though you have your
own distinct genome, it is still recognizable as a human genome.
Analyzing the human genome will give us insights into why people like the foods
they do, why certain people die of heart disease and others of cancer, and why some
people are outgoing and others are paralyzed by shyness. We will also be able to know
what body shape your children will have, the number of calories they are able to burn off
in rest, and the types of sports they will excel at and enjoy. Studying the genome can
related to a number of things, you can study the whole genome, or only a small part. You
can study the sequence, or function of a specific gene.
We are able to observe what happens when something goes wrong with a gene,
and how it affects our life and body. Certain diseases are cause by mutations in a particular
gene such as Blindness, cancers, bowl disorders, Leprosy, arthritis, Turner’s syndrome,
Down Syndrome, and many other types of diseases. These genetic diseases are caused by
changes (mutations) in the DNA sequence of a gene or a set of genes. This can happen at
any given time, from when we are a single cell to when we are close to 100 or older. Some
scientists believe that there are specific disorders genes that cause the disease, but it is a
mutation that causes the normal genes to operate improperly. So to clarify all the mishap it
is better to say that there are mutated genes that cause genetic disorders.
In some diseases such as Down Syndrome and Turner’s Syndrome, entire
chromosomes, or large segments of them, are missing, duplicated, or otherwise altered.
Single-Gene disorders result when a mutation causes the product of a single gene
to be altered or missing. Sickle-cell Anemia is an example of this type of disorder.
Mutations in the beta-globin gene cause the blood cells to become distorted and take on a
sickle shape. This makes traveling through the blood vessels hard and they begin to clog in
the narrow passages, causing various problems within the body depending on where the
clog is at.
Multifactorial disorders result from mutations in multiple genes, often coupled with
environmental causes. The complicated bases of these diseases make them strenuous to
study and treat. Some examples of this type of disorder are heart disorders, diabetes, and
cancers. Certain kinds of thyroid cancers are accumulated by malfunctioning genes, such
as Familial papillary thyroid cancer, and Medullary thyroid cancer (Article #5). Cancer is
caused by certain changes in our DNA sequence. But cancer is not developed by one
mutated gene, its the accumulation of many defected genes. This can happen through
inheritance of mutations or addition of new mutations during the life span of an organism.
Additions of new mutations can come from exposure to the sun, UV rays, infection by
certain viruses, spontaneous mutations and changes in copying the DNA during the aging
process. The genetic basis of cancer is possible by the cancerous cell dividing at
inappropriate times. This could mean that the cells either do not receive the signal to stop
dividing or they do not require outside signals to start dividing, so they divide when they
feel like it. When cancerous cells come in contact with other neighboring cells they do not
stop dividing like normal cells do, but they pile up and form a tumor. Cancerous cells also
have the ability to invade healthy tissue, leading to the spread of cancer throughout the
Scientists were able to pin down the exact gene that is responsible for prompting
people’s internal wake-up alarms. A mutation in this gene can cause the person to wake
up at very inappropriate times and causes them to become tried in the middle of the
afternoon. The mutation was found in the human Per2 gene on Chromosome 2. This is
common to many people the statistics show 1 in every 10,000 all the way up to 1 in every
100,000 people. There are a large quantity of people that don’t realize that it is a disorder
so they never come in for treatment (Article #3)
Colourblindness is another of the many generic disorders. It is found in the X
chromosomes which is passed down from the female, never the male. If a woman with the
gene that entitles Colourblindness has a girl, the X chromosome of the baby will cancel
out the colourblind chromosome (X) a majority of the time. There is a slim chance that
when the X chromosome of the baby is weak the colourblind X will prevail and the girl
will be born colourblind. Females are the only carriers of this generic trait, very rarely does
a female get the trait. If that same woman were to have a boy, the X chromosome will
predominate the Y chromosome and the boy will indefinitely be colourblind. The ratios of
this disease are very different for men and women, 1 in 12 for men, and 1 in 250 for
women. Inherited genetic mutations arise about twice as often in men as in women
Scientists have found that a retinal gene appears to be responsible for at least some
of the cases of macular degeneration, or blindness. The gene, which plays a role in the
metabolization of a fatty acid called DHA, has become defective and does not perform its
assignment accordingly. This suggests that people with the defected genes may have
trouble using the fatty acid in normal cell mechanisms. This leads to the deterioration of
the macula, a central part of the retina responsible for sharp, central vision. The loss of this
vision limits what a person can do, such as driving which is no longer acceptable, they
have trouble reading, and they lose all peripheral vision. This defective gene is past down
from generation to generation. To help cut back on the problems that can be caused by
eating foods that are high in DHA, such as salmon, shellfish, eggs, tuna, liver, and many
more (Article #2)
The entire genetic sequence of the disease labeled Leprosy has been deciphered.
This shows that with genetic sequencing of different organisms, such as the Leprosy
Bacterium, is extremely helpful in finding new, efficient treatments and drugs. In the case
of Leprosy it also help scientists to calculate how to grow the bacterium in a laboratory
which was impossible up to now (Article #8).
Ankylosing Spondylitus, or spinal arthritis is also formed from gene mutation. The
gene attacks the spine making it rigid as a poker, the extreme case, to just not allowing to
move easily, the moderate case. With learning how the gene is able to make this happen
we will be able to treat this, and maybe even cure it (Article #7).
Other disorders are not caused by malfunctioning genes or abnormal
chromosomes, but certain viruses can infect a gene and that gene will multiply with that
infections written in it. AIDS is a worthy example of this type of disorder or disease.
AIDS is cause by an infection with the HIV virus. The HIV virus infects an organism
incorporating its own DNA into the chromosomes of the infected cell. When this cell
divides, the viral DNA is inherited by all the daughter cells of the infected cell. So in a way
the infected cell now has a genetic disorder, caused by the introduction of a new DNA into
its chromosomes. The viral DNA will not transfer onto the next generation because the
sperm and egg cells of the organism are not daughters of the infected cell.
Scientists have recently been able to manipulate a skin cell to turn into heart tissue.
This can be radically helpful in the production of islet cells that produce insulin needed for
diabetes. The scientists “turned the clock back” on the skin cells to produce stem cells,
which have the ability to develop into any desired type of cell, from nerve to liver to
muscle. Then they manipulate the stem cell to become a heart tissue. This could be a
breakthrough for diabetic people, eliminating the daily insulin shots, and making live just a
little it easier (Article #18).
Tests with possible cures are been research continually, such as with tobacco
plants that contain a human gene. The gene interleukin10 can be massed produced to help
treat bowl disorders. Using genes from other living organisms are growing more common
in science (Article #4).
To stop the wide shortage of organ transplants needed, scientists have started
researching “humanized” pig organs. The birth of a litter of genetically modified pigs have
started this research. Each of the pigs has a “marker gene” introduced into its genetic
code. This produces a knock-out pig, where scientists will knock out the gene that leads
to the human immune system. This will eliminate the rejection of the pig’s organs when
placed in the human body. The process is called Xenotransplants, and it could start in as
little as 4 years (Article #19)
In the same sense scientists have been able to turn a plant’s leaves into petals,
allowing nurseries to produce plants that bear flowers where leaves were. This is possible
by five genes that are manipulated, either by traditional breeding, or by genetic
engineering. Breeders will be able to make colourful double flowers in which stamens and
leaves grow into petals and enhance the fragrance. This not only could help the nurseries
but the drug industry as well, by allowing them to grow greater quantities of therapeutic
chemicals that come from flowers (Article #17).
Additional traits can be discovered by sequencing the genes. Not only will
scientists be able to see whether or not you have a fatal disease, but they will be able to
envision what type of body type your child will have, what kind food they will have a taste
for and whether they will be outgoing or paralyzed with fear about leaving the house.
There are innumerable amount of traits that we will be able to see when we look at a
persons genes. What kind of sports they will like, whether they will be overweight or
underweight, how many calories they burn at rest, and whether they are a psychopathic
killer (Article #9). We will be able to know ahead of time what kind of lives our children
will lead, in some ways this is a good thing because it will prepare us for what type of
parenting we have to do. But in other ways if we find out what likes and dislike our child
will have we will have the choice, if we want this child or not, this exact thought raises
many questions about the morality of genetic sequencing.
Scientists have just encountered the gene that controls the height of humans also
governs life and death, meaning that short people are genetically programmed to live
longer than tall people. Using Nematobe C.Elegan, worm-like creatures, scientists
eliminated these genes and the result is either mutant giant, or dwarf worms. They
discovered that the genes that were “knock out” which produce growth hormones, also
influence life expectancy. The lower levels of growth hormones, the longer the life
expectancy. Even though it was only tested on C. Elegans, human have the same
insulin-based growth system, so it applied to humans as well (Articles #20,25).
A discovery has been made that there is a gene that explains why moderate
drinking can prevent heart attacks. This gene, or variants of it, makes the body break
down alcohol very slowly which raises the levels of heart-protecting “good cholesterol” in
the blood. Drinkers with this gene were found to have a sharply lower risks of heart
attacks than those that dispense alcohol at a faster rate. The gene produces enzymes called
alcohol dehydrogenase that breaks down alcohol. The gene either breaks down the alcohol
quickly or slowly. You inherit one of the genes from each parent, so you can have two fast
genes, two slow genes, or one of each. Those who have two slow genes and average one
drink a day have a 85% less risk of a heart attack than those who have two fast genes and
hardly drink. With conditions such as obesity, overdose of alcohol, smoking, and a history
of heart illness the risk was still 35% lower (Article #16).
Jurrassic Park the movie directed by Steve Speilberg, based on a book by Michael
Crichton, has raised many questions about the correctness of taking DNA found in fossils
and decoding it. Geologists right now are extracting the DNA from prehistoric bugs’
stomach. If the chance that the DNA turns out to be belonging to a dinosaur they want to
decoded it and possibly clone a dinosaur. Cloning is made from a single adult cell joined
with an egg cell, the genes of which have been removed, so all the geologists need from
the DNA of a dinosaur is the adult cell, and an egg cell. If the geologists decide not to
clone the dinosaurs then they will use the DNA to find out a little more about dinosaurs
and the environment in which they lived (Article #10).
Apart from just studying the DNA and sequencing the genes, the knowledge of the
DNA can be used in fighting crimes. Any type of body fluid and cells can be used to find
out who was present at the scene of a crime. Evidence such as sperm, blood, pubic hair,
skin cells, and saliva can be taken into a lab and studied to find out who exactly it belongs
to. This is accomplished by searching a computer from a DNA Databank. A DNA
Databank keeps records on the DNA of everyone they possibly can, for use in such
situations as a crime scene investigation. Once the investigators have a list of possible
people that are suspected, they now go and get a swabbing of the inside of their mouths
for further testing. People have rejected this, calling it an invasion of privacy. They believe
that if employers were to be able to have access to the DNA Databank they would know
all about their employee including diseases or disorders, characteristics and traits. Meaning
that if your employers looks at your DNA and finds that you have a history of heart
disease in your genes and they believe that you are not fit for the job they can fire you on
that account. This is a downfall of keeping DNA files on hand, they can be used against
people, not just to help them (Articles #11,12,13,14,15)
Scientists have not just been mapping the code of human and animals, but of plants
as well. They have been able to genetically modify plants to help them survive longer and
produce better food, flowers, or fragrance depending on what they want enhanced.
Genetically Modified foods have become more common in recent years. It was mostly
grains that have been engineered with genes from non-grain species that make the plants
resist insects or tolerate pesticides. So a farmer can spray his crops with a pesticide and
have it kill everything in its field except his harvest. There are some problems with this,
such as allergies in humans. Scientists have yet to figure out whether or not people can
develop allergies towards GMOs, but some people don’t want to take the chance. The
pesticide resistant plants could jump to wild plants, creating “super-weeds” or could harm
valuable insects by making their food unfit to eat, such as the Monarch butterfly. The
Genetically Modified Atlantic and Pacific salmon are growing faster than normal salmon, if
the super-salmon were to escape from the production plantations, they could mate with
normal salmon and corrupt their whole genetic pool. There is also problems with patent
genetically modified plants, if a person suspects that his neighbor was stealing his
super-seeds, the only way to prove he’s not is to spray his field. If the crop dies then he is
not stealing the crops, but he lost all that years harvest. If the crop lives, then the company
can sue the neighbor. So you can see that there is a number of problems that could arise
with releasing the GMOs. Some Health officials don’t agree with Genetically Modified
foods, claiming that it is unhealthy and dangerous to humans and the environment, if not
properly controlled. Right now in Canada they are looking for better ways to control
GMOs and the sale of them. Officials believe that their will be a lot of problems with
GMOs and how people will react to them being on the shelf, they think that there will be
destruction of fields and food products just like the reaction in Europe last year.
After figuring out the genome of humans there is still Protenome, a complete
listing of the 250,000 or so proteins that the 35,000 genes are capable of making. Proteins
can vary in health and disease, and the long chains of amino acids do not string out but
curl up on themselves in complex 3D shapes, making it indefinitely harder to break the
code. “Most of biology happens at the protein level, not the DNA level,” Dr. Craig Venter
of Celera Genomics points out. Scientists not only have to figure out what the listing of
proteins is but how they change in disease and how they fold. This is dubbed the “Greatest
unsolved problem in biology.” (Article #27)
As you can see there is still a long way to go in finding out everything there is to
know about Genetics. But when we do find out everything about Genetics and the human
body, there is nothing left to the imagination, and a part of that will be sorely missed.