tests can be broadly classified into three types. These tests help in
determining the pattern of the genes and their alignment. Different types of
genetic tests are recommended by doctors for different reason. Read on to know
in detail about these tests.
Doctors recommend different types of genetic
tests depending on the reason that necessitates the test. Broadly there are
three types of genetic test, and quite obviously all of them are related to
gauge the pattern of the genes and how they align with the condition that the
doctor fears to be present or not present in the patient. They are as follows.
- Gene Test – The DNA and RNA are tested in this type of genetic testing and they are usually obtained from individual genes. They need to be of a relatively shorter length.
- Chromosome Test – DNA belonging to the longer length are tested here. They are a part of the whole chromosomes.
- Biochemical Test – In this type of genetic testing, either the protein level of the enzyme activity of the person is tested.
of Genetic Testing
The purpose and necessity of the tests are discussed
test is conducted obtaining a sample of the individual’s blood or any other
bodily fluid like saliva or tissue. The DNA and RNA are tested as the doctor
basically searches for a disorder pattern that might be present in the test
results. This helps him to ascertain whether the signs of the disease that he
had suspected are also present in the person.
Often a gene can have a missing or additional section
that makes it unique. These are major changes that the gene test can figure
out. There can also be smaller changes taking place within the DNA strand like,
the subunit or the chemical base stands changed. This changes can happen when a
section is missing, added or altered.
Genes that have numerous copies are also identified
along with those individual genes that are hyperactive or those that are not
functional at all. Gene tests also determine the genes that have been entirely
lost in the individual.
The DNA of the individual is determined through gene
test in a number of ways. For instance, a DNA probe can be conducted on a short
string of DNA that has its base sequence that can bond with another sequence of
an altered gene. The probes are identified with the fluorescent tags. This
helps in seeking out its compliment in the individual’s genome. The moment it
finds it altered gene, it binds with it and the alteration is tracked with the
help of the florescent tag.
Gene test also requires DNA or RNA sequencing. Here
the DNA or RNA of the individual’s sample is compared through a base by base
sequencing with a normal version of a DNA or RNA sequence.
The nucleus of a cell contains the chromosome which
happens to be the large DNA containing structure. We have 22 pairs of autosomes
and 1 pair of sex chromosomes giving it a total of 23. The chromosomal test
gives an insight into the individual’s chromosomes which includes their
definite structure, number and arrangement.
There can be a number of changes that can take place
like a pair or pairs being totally absent; some can get expanded, while some
can even switch to a different chromosomal location. All of these can be
identified through the chromosomal test. There are two types of chromosomal
offers the entire chromosome structure of the individual, beginning from the
largest to the smallest. The test reveals the full detail of any possible
alteration in a specific chromosome number along with the ensuing alterations
in the DNA structure.
Analysis – This is an abbreviation of ‘fluorescent in situ hybridization’
test uses fluorescent DNA probes. There can be sections of chromosomes that can
be missing or have extra copies. The FISH analysis identifies these changes.
The key proteins play a major role in the
disease condition or the manifestation of the sign and symptom of the same.
Through a biochemical test the doctor gains an insight into the activities of
these key proteins.
The secret of protein buildup lies in the DNA code. You can understand that the
genes are not functioning in the expected manner when there is an abnormal
amount of protein or there is a change in the protein.