Genetic Counseling
Genetic counseling is the process in which parents (who are at risk for their child
having a genetic disorder) are advised the procedures and risks that come with having a
child. It is a genetic counselors job to indicate the possibility of transmission, and how
severe the case can be. This topic is very prominent in modern society and involves a large
group of people. Counseling mainly involves people with genetic disorders inherited in
their family; however it can be useful in a population in determining a recurring disorder in
a large population. Genetic Counselors are often present at prenatal clinics as well as adult
genetic centers and are a valued assistant to physicians. Any person is able to make an
appointment with a genetic counselor if a risk is discovered through a prenatal test or
diagnosis. During an appointment, counselors are supposed to give non-biased, vital
information to ensure the parents understanding of the chances for different disorders to
be expressed. Often times testing proves to be accurate and reveals conditions which are
easily solved when treated properly.
Cloning
Cloning is the process utilized to create a genetically identical organism through nonsexual means. There are essentially two main types of cloning: artificial embryo twinning and
somatic cell nuclear transfer. Artificial embryo twinning is considered to be the more natural
approach with regards to cloning. Identical twins are formed when a zygote splits into two cells
each of which contains identical genetic information. Artificial embryo twinning is done by
manually separating a very early embryo into two distinct cells. These cells develop and grow on
their own, and are eventually placed in an alternate (or surrogate) mother where they are carried
to term and delivered. In a somatic cell nuclear transfer, the nucleus of a somatic cell is removed
and preserved. The nucleus of the host’s egg cell is removed and is thrown away. The lone
nucleus is then integrated with the enucleated egg cell. The egg cell with its now, new nucleus
resembles a freshly fertilized zygote. Similar to artificial embryo twinning, it is now placed in a
surrogate mother, carried to term and delivered. There are many uses for cloning, including the
mass production of organisms with certain particular qualities which you otherwise risk breeding
out. It remains unclear what the world of cloning entices for us, however, one thing is for sure,
we can expect it to be a part of our daily lives in the near future.
Well laid out diagram of somatic cell nuclear transfer (above).
Genetic Engineering/Selective Breeding
Genetic engineering/selective breeding is the technological way of changing the genetic makeup of cells and
movement of genes to make new organisms. Animals, plants, and bacterium are all affected by this modern process
of creation. The purposes of this engineering are to create clones of the ideal plant or animal disease curing, better
survival, and convenience for society (such as food and environment). For example, Pamela Ronald, a professor of
plant pathology at the University of California-Davis, developed a flood-tolerant strain of rice seed because the rice
crops in China were constantly flooded. Using a gene of the wild rice in Mali that can withstand water for 17 days,
Ronald helped support thousands of impoverished farmers in China.
The process of genetic engineering is like taking a recipe out of a cookbook and placing it in another cookbook. The
first step is to find an organism that naturally contains the desired traits. The next step is called mapping, where the
scientist finds and isolates the genes with the desired traits. Then, the scientist makes several copies of the isolated
gene using a technique called PCR (polymerase chain reaction). After that’s done, there are different ways to insert
the desired genes into an organism. The most common method used for plants is using certain bacteria (like
Argobacterium); the gene is inserted into the bacteria, which naturally delivers it into the cells of recipient plants.
Then, the scientist checks if the inserted genes function as expected in the organism and they appear in the progeny
of the organism as well.
With genetic engineering, risks also come along with the benefits. Genetically-altered crops could contain unknown
substances or unwanted traits that could be potentially harmful to our health. But usually they are uncommon since
those crops are only altered to a certain degree so breeding a crop that could be harmful to our health is not as
common and the engineers would test it first to make sure it is safe to consume before putting it on the market.
However, they could be harmful to the environment because of the alteration. They could become invasive or
parasitic to other organisms. If this gets serious, a species of organism could go extinct because of these genetically
altered plants or they could cause ecological disasters which indirectly affects us humans. For example, millions of
U.S. farmlands are infested with weeds because of genetic engineering. Many farmers began to use Monsanto's
"Roundup Ready" trait on their farms to increase profit. However, it is engineered to tolerate the herbicide and
several weed species has grown to have stronger resistance against herbicides.
Genetic Engineering Process
Genetically Engineered Crops
Epigenetics
Epigenetics, literally “above genetics”, is the study of hereditary changes in gene activity
caused by environmental factors rather than changes in DNA sequence. The changes in gene
expression are shown in the phenotype rather than the genotype, meaning that there may be a
visible change in appearance. However, these changes do not involve an alteration of the
nucleotide sequence.
Examples of mechanics that produce epigenetic changes include histone modification and
DNA methylation. Histones are a family of basic proteins that associate with DNA in the nucleus
and help condense it into chromatin. Histone modifications affect chromosome function by
altering the electrostatic charge of the histone, which leads to their structural change or their
binding to DNA. DNA methylation is a biochemical process involving the addition of a methyl
group (CH3) to the cytosine or adenine DNA nucleotides. It alters the expression of genes in cells
as they divide and differentiate from embryonic stem cells into specific tissues, but does not alter
the integrity of the actual genetic material.
The influence of epigenetics is evident in everyday life. People that eat healthy, exercise
daily, refrain from smoking and drinking, will have a healthier appearance than those that don’t.
People that have a stable job and experience less stress will also look better than those that are
struggling to get by and under lots of pressure. As a result, people that maintain a good lifestyle
will have fewer wrinkles, acne, and will most likely be less susceptible to diseases such as
cancer.
This man’s face is a perfect example that shows the impacts of epigenetics. He was a
trucker who drove the same route every day, and the sun hit the same side of his face his whole
life. This caused the skin of the left side to appear older and wrinkled compared to the right side
of his face.
Epigenetics has an effect on every organism; the effect environment plays on an
individual is inevitable. One individual can express a completely different appearance in two
different environments This goes to explain how even identical twins grow dissimilar as a result
of their respective environments.
In vitro fertilization
Definition
In vitro fertilization (IVF) is a process where an egg is fertilized by sperm outside of the
body.
Process
There are five basic steps to IVF:
1. Medicines are given to the woman to stimulate the production of eggs.
2. The eggs are removed from the woman’s body through surgery
3. The sperm of the man is secured and used to fertilize the highest quality eggs
retrieved from the female in a laboratory
4. Following the insemination, the egg develops into an embryo, which is monitored
and taken care of in an appropriate environment
5. The embryo is placed back into the woman’s womb. This step generally occurs 3-5
days after insemination occurs
Why it is Performed
In vitro fertilization is performed to allow a woman to become pregnant. It is an effective
process used to treat various cases of infertility, generally between couples who are unable
to conceive a child through sexual intercourse.
Risks
There is a risk of multiple pregnancies when more than one embryo is placed in the womb,
which may lead to premature birth and low birth weight.
Risks of egg retrieval include bleeding and damage to structures surrounding the ovaries,
as well as infection. The patient may also experience various symptoms and reactions to
anesthesia.
IVF is also a very expensive process, and may cost in excess of 12,000 - 17,000 dollars.
Artificial Insemination
Artificial insemination is a technique that can help treat certain
kinds of infertility in men and women. This process gives the
couple a chance to conceive a child. In this procedure, sperm are
inserted directly into a woman's cervix, fallopian tubes, or uterus.
This makes the trip shorter for the sperm and bypasses any
possible obstructions, increasing the chances of fertilization to
occur.
Who Does This Apply To?
Artificial insemination is a common technique used for couples in which the male has a very low
sperm count or sperm that aren’t strong enough to swim through the cervix and up into the
fallopian tubes. This technique also applies to women who have endometriosis or abnormalities of
any of their reproductive organs. Furthermore, women with “unreceptive cervical mucus” are good
candidates for this procedure. In these women, the mucus surrounding the cervix is hostile to
sperm and does not allow sperm to pass through to the fallopian tubes. However, this procedure
allows the sperm to pass the cervical mucus entirely making the trip much easier.
Procedure
When the female is ovulating, the partner is asked to provide a sample of semen. Within one hour of
ejaculation, the sperm is “washed”. Washing consists of
liquefying the sperm at room temperature for 30 minutes in
order to enhance the chances of fertilization. After this step, a
harmless chemical is added to the semen to separate the most
active sperm. Then, a centrifuge is used to collect the best
sperm. During this process the most active semen rise up to
the top of the tube and these sperm cells are the ones that are
used in the procedure. Once the sperm have been collected,
the cells are inserted into the female’s cervix, fallopian tubes,
or uterus by the use of a catheter. After the sperm are
introduced, the most active sperm cells make their way to the
female egg. When a sperm cell has been selected, the process
of fertilization begins, leading to the formation of a zygote, which eventually leads to the
development of a fetus.
Additional Facts
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Involves little- to-no side effects and is a simple procedure
Often recommended as the first type of treatment for infertility due to these reasons
Success rates range from 5 to 25 percent
Older age of woman, poor sperm and egg quality, and endometriosis are some factors that
lessen the chance of success
Fetoscopy
A fetoscopy is a rarely used technique that uses a scope to examine and perform procedures on a
fetus when in a situation with a high possibility of giving birth to a baby with birth defects (often first
seen through ultrasound). It’s basically a visual assessment of any abnormalities during pregnancy.
Although not done often, fetoscopies are used for several different diseases and has been used to perform
surgical procedures and collect biopsies. Generally performed under anesthesia and in an operating room,
a small skin incision of 1 mm is made to allow a scope to enter. Once it enters, a doctor will perform the
procedure needed or collect what’s needed. Disease conditions that routinely utilize this technique as
treatment are Twin-Twin Transfusion Syndrome, Amniotic Band Syndrome, and Congenital
Diaphragmatic Hernia. The test is also used to check for the presence of spina bifida, a type of neural tube
defect. Fetoscopies have risks (injuring and losing the fetus), but risks and benefits can be weighed
between the patient and doctor.
Amniocentesis
Amniocentesis (also known as an amniotic fluid test) is a procedure in which the fetus/embryo is
tested for diseases and or conditions before it is born. There is amniotic fluid in the amniotic sac
which helps to nourish and protect the baby. This amniotic fluid in turn contains the genetic
information that the baby will be born with. In this procedure, doctors put a needle into the
amniotic sac and extract a bit of the amniotic fluid while performing an ultrasound. They carefully
extract the fluid while looking at the ultrasound to make sure the needle doesn't harm the placenta
or the baby. Lastly, the baby is monitored to make sure his/her heartbeat is normal and that the
procedure isn't putting too much pressure on the baby. If anything abnormal surfaces during the
procedure, it is stopped immediately as safety is always number one. Once the extraction is
finished, it can be tested for genetic disorders or abnormalities such as neural tube defects, Down
syndrome and other conditions as it contains the same genetic information that the baby will be
born with.
This procedure is usually performed in the second trimester when the embryo is about
fifteen to eighteen weeks old. Amniocentesis may be highly recommended by doctors for some
mothers who are 35 years or older as older women are linked with having a greater chance of
having children born with Down syndrome. Also this procedure can be recommended if mothers
have had any previous children born with birth defects, or coming from a family with a history of
genetic disorders. This procedure can help rule out any other complications that the child may be
born with so that doctors can have some insight and be prepared for the delivery.
Lung development is another key reason for performing this procedure, which would occur
in the third trimester. Doctors can once again test the amniotic fluid to determine whether or not
the baby’s lungs have developed sufficiently to keep the baby alive. Overall this procedure is
extremely helpful for doctors, the parents and most importantly the baby as it can be that saving
grace. Using amniocentesis, doctors can prevent these abnormalities or at least be prepared for
them, possibly being the difference between life and death. This used to be a complicated
procedure, but with medical advancement it has become so efficient and effective. It is
recommended everywhere.
Stem Cells
What are Stem Cells?
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Stem cells are a special type of undifferentiated cells that have the ability to differentiate into
specialized cell types. In other words, stem cells are simple cells which have the ability to become
more complex in order to fulfil a more specific function.
Activate when necessary, such as during injury or disease.
Exist in various types of tissues (brain, bone marrow, skeletal muscle, skin, liver, etc)
2 main types: adult stem cells, which can renew/divide indefinitely but are multipotent, oglipotent
or unipotent, and embryonic stem cells, which are formed only during development of the embryo
but are totipotent or pluripotent.
Stem cells can be further classified into 5 different categories based on how many different cell
types they can differentiate into.
Type
Description
Examples
Totipotent
Can differentiate into any cell type.
Zygote formed at fertilization
Pluripotent
Can differentiate into almost all cell
types.
Stem cells derived from the
mesoderm, endoderm and ectoderm
germ layers formed early on in
embryonic development.
Multipotent
Can differentiate into a closely
related family of cells.
Hematopoietic stem cells can divide
into white or red blood cells.
Oligopotent
Can differentiate into very few cell
types.
Adult lymphoid cells
Unipotent
Can only produce cells of their own
type. They have the property of cell
renewal, so are technically
considered stem cells.
Muscle stem cells
Diagram of a
pluripotent stem
cell and its
possible
differentiations.