What are genes?
Segments of DNA that contain instructions for making proteins
DNA segments consist of what?
Exons and introns
What are exons?
coding regions
What are introns?
noncoding regions that are typically edited out during mRNA editing
Humans have how many genes?
20,000 to 25,0000
Variants if genes are called what? What are they responsible for?
Alleles and they are responsible for differences seen
between
individuals of the same species
What are mutations in genes?
They are any change in the nucleotide sequence
of a gene, which
can affect one or more nucleotides
True or false. Mutations can be beneficial, neutral, or harmful.
True
What are they types of mutations that can occur?
Point mutations, Insertions/Deletions, Frameshift mutations, Duplication mutations, Inversions, Translocations
"pretty interesting fish dive in tanks"
What are point mutations?
It is when a single nucleotide is altered.
What is an example of point mutations?
sickle cell(missense) and Beta Thalassemia(nonsense)
What are the 3 different categories of point mutations?
Silent: Even with the new nucleotide the amino acid
is not changed
Missense: The mutation results in a different amino acid
Nonsense: Creates a premature stop codon, the protein
will be shorter than anticipated, which could render it nonfunctional
What are insertion and deletion mutations?
It is either the addition or loss of one or more nucleotides. It can lead to a frameshift mutation.
What is an example of an insertion mutation?
Tay-Sachs Disease: Occurs when a four base pair insertion in the HEXA gene, which leads to the destruction of nerve cells in the brain and spinal cord.
What is an example of a deletion mutation?
Cystic fibrosis: When a three-base pair deletion in the CFTR gene, which leads to the production of a thick and sticky mucus caused by the misfolded protein
What is a frameshift mutation?
It is caused by insertions or deletions that are not in a multiple
of
three. Creates a completely different protein, which can
hinder it
nonfunctional
What are examples of frameshift mutations?
Duchenne Muscular Dystrophy: Caused by insertions or deletions in the dystrophin gene on the X chromosome. This causes progressive muscle weakness and degeneration
Familial Hypercholesterolemia: Affects the LDLR gene creating a mutation in the LDL receptor, which allows LDL cholesterol (“bad” cholesterol) from passing from the blood to cells for use
What is a duplication mutation?
Segment of DNA is duplicated, resulting in multiple copies
of
that region
What is an example of duplication mutations?
Charcot-Marie-Tooth Disease: Caused by duplication in PMP-22 gene, leading to damage to peripheral nerves. Also known as HMSN and PMA
Huntington’s Disease: Caused by a duplication of CAG repeats in the HTT gene on chromosome 4. This causes deterioration to nerves in the brain when a person reaches their 30s or 40s
What is a inversion mutation?
A segment of DNA is flipped in orientation within the chromosome
What are examples of inversion mutations?
Hemophilia A: Individuals have a lack of blood
clotting
factor VIII, leading to excessive bleeding
Breast cancer, stomach cancer, and T-cell lymphoma
What is translocation mutation?
When a segment of DNA is moved from one location in the genome, including being moved to a different chromosome. When 2 independent genes create a single hybrid gene
What are the examples of translocation mutations?
Chronic Myelogenous Leukemia: A translocations
between chromosomes 9 and 22, creating the BCR-ABL fusion
causing
uncontrolled cell division. Results in bone marrow producing too many
white blood cells
Burkitt Lymphoma: A translocation involving MYC gene and immunoglobulin genes, overexpressing MYC. Usually develops after acquiring immunodeficiency from Epstein-Barr Virus or HIV