DNA Polymorphisms in Medicine

Question 1

Oligonucleotides

Answer 1

Oligonucleotides are short strands of nucleic acids, typically composed of 13-25 nucleotides, which are the building blocks of DNA and RNA. Oligonucleotides can be synthesized in the laboratory with specific sequences of nucleotides, allowing for the creation of custom-designed DNA or RNA sequences.

There are several types of oligonucleotides with different applications, including:

Primers: Short oligonucleotides used as starting points for DNA replication or polymerase chain reaction (PCR) amplification.

Probes: Oligonucleotides labeled with a detectable signal, such as a fluorescent molecule, used to detect specific DNA or RNA sequences.

Antisense oligonucleotides: Short DNA or RNA sequences that can bind to specific messenger RNA (mRNA) molecules and block their translation into protein, potentially providing therapeutic benefit for various diseases.

Aptamers: Oligonucleotides that can bind to specific target molecules, including proteins, with high affinity and specificity, making them useful in diagnostic and therapeutic applications.

Question 2

SNPs

Answer 2

Single nucleotide polymorphism; any two individuals that have thousands of positions in their genome that differ by a single nucleotide;
SNP chip contains many spots of many DNA strands of. A specific DNA region can be present on more than one spot, but many regions are not present on any spot.

Question 3

How many base pair DNA do we have?

Answer 3

Human genome is estimated to contain approximately 3 billion base pairs of DNA

Question 4

How many rare variants do we have in our gene?

Answer 4

150 genes, 1%

Question 5

Polygenic Diseases

Answer 5

Multiple genes collaborate together to produce a phenotype; i.e. a disease requires multiple gene mutations
A polygenic disease is a disease that is associated with mutations in more than one gene. For many polygenic diseases, the mutations associated with the disease do not directly result in a disease phenotype but are, instead, correlated with an increase in the risk of having the disease phenotype.

Question 6

Monogenetic diseases

Answer 6

Huntington’s disease
cystic fibrosis

Question 7

What is the difference between ALL and AML?

Answer 7

ALL (Acute Lymphoblastic Leukemia) and AML (Acute Myeloid Leukemia) are both types of acute leukemia, which are cancers that affect the blood and bone marrow. However, there are some key differences between the two types:

Cell type: ALL is a cancer of the lymphocytes, a type of white blood cell involved in the immune system, while AML is a cancer of the myeloid cells, which give rise to red blood cells, platelets, and other types of white blood cells.

Age of onset: ALL is more common in children, while AML is more common in adults.

Symptoms: The symptoms of ALL and AML can be similar, such as fatigue, weakness, fever, and frequent infections. However, ALL may also cause bone pain and swelling, while AML may cause easy bruising or bleeding.

Question 8

What is the difference between recurrence and metastases?

Answer 8

Recurrence: Refers to the return of cancer in the same location or area where it was originally diagnosed and treated. This can happen if some cancer cells were left behind after treatment, or if new cancer cells have developed from remaining cells that were not eliminated.

Metastasis: Refers to the spread of cancer to a different part of the body from where it originated. This occurs when cancer cells break away from the primary tumor, enter the bloodstream or lymphatic system, and then grow in a different part of the body. Metastases can occur in any part of the body, but common sites include the lungs, liver, bones, and brain.

Question 9

Protein Localization on the Genome

Answer 9

1. Obtain cells with estrogen receptor bound to the genome.
2. Add a chemical that cross-links proteins to DNA.
3. Randomly cut the DNA.
4. Add an antibody that specifically recognizes the estrogen receptor protein.
5. Using one of many biochemical techniques, purify the antibody attached to the estrogen receptor protein with the attached DNA.
6. Isolate the bound DNA from the protein and sequence the DNA.
7. Map those sequences to your reference genome sequence to determine their locations.

This technique is called ChIP-seq, or Chromatin Immunoprecipitation - sequencing