From Genes to Genetic Diseases
DNA Research Paper
Ashtyn Brewster (AB10724)
Determining How a Disease Gene Is Mutated
2.
2a.
Cystic fibrosis is an inherited disease that causes a mucus buildup in the respiratory and
digestive systems. The mutated gene that causes cystic fibrosis is called CFTR. CFTR gene’s job is
to provide the cell with instructions for making and providing a channel that transports chloride
ions in and out of the cell. With the mutation the CFTR gene is unable pass the chloride ions and
water through the membrane which causes a build-up of sticky mucus blocking airways. This
causes the body to have trouble breathing and may cause a bacterial infection in the lungs.
2b.
i.
The symptoms and problems of cystic fibrosis include chronic digestive system
problems and damage to the respiratory system.
ii.
The mutated gene that causes cystic fibrosis is the CFTR gene.
3.
4.
4a. The CFTR gene belongs to the family of ABC (ATP-binding cassette transporters) genes.
4b. The CFTR gene is located on chromosome 7q31.2.
4c. The amino acid most commonly mutated to cause cystic fibrosis is F508.
5.
5a.
Genes of the ABC family provide instructions for making proteins that transport and
carry molecules such as fats, sugars, amino acids and drugs across the cell membrane.
5b.
All of the genes in this family are grouped together because they have common
structures that bind to ATP.
From Genes to Genetic Diseases
DNA Research Paper
Ashtyn Brewster (AB10724)
From DNA to Amino Acids
1.
Transcript
Mutation
1408G>A
1516A>G
4002A>G
2694T>G
4521G>A
rsID
rs213950
rs1800091
N/A
N/A
N/A
Codon
Sequence
Change
(DNA)
GTG →
ATG
ATC →
GTC
CCA →
CCG
ACT →
ACG
CAG →
CAA
Codon
Sequence
Change
(mRNA)
GUG →
AUG
AUC ->
GUC
CCA ->
CCG
ACU ->
ACG
CAG ->
CAA
Amino
Acid
Sequence
Change
Effect
Pathogenic
or NonPathogenic
V [Val] →
M [Met]
Changes from
a neutral,
nonpolar
amino acid to
another
neutral,
nonpolar
amino acid.
NonPathogenic
L [Lle] ->
V [Val]
Changes
from a neutral
nonpolar
amino acid to
another
neutral,
nonpolar
amino acid.
NonPathogenic
P [Pro] ->
A [ Ala]
Changes
from a polar,
uncharged
amino acid to
a nonpolar
amino acid.
NonPathogenic
T [Thr] ->
T [Thr]
Changes
from a polar,
uncharged
amino acid to
another
uncharged
amino acid.
NonPathogenic
G [Gln] ->
G [Gln]
Changes
from a polar,
uncharged
amino acid to
another
NonPathogenic
From Genes to Genetic Diseases
DNA Research Paper
Ashtyn Brewster (AB10724)
uncharged
amino acid.
1477C>T
1013C>T
1040G>T
1645A>C
1727G>C
Rs7710217
Rs77409459
Rs77932196
Rs121908757
Rs1800098
CAG ->
TAG
ACC ->
ATC
CGG ->
CAC
AGT ->
CGT
GGA ->
GCA
CAG ->
UAG
ACC ->
AUC
CGG ->
CAC
AGU ->
CGU
GGA ->
GCA
G [Gln] ->
Stop
Ends from a
polar,
uncharged
amino acid.
Pathogenic
T [Thr] ->
L [Lle]
Changes
from a polar,
uncharged
Amino Acid to
a nonpolar
amino acid.
Pathogenic
A [Arg] ->
H [His]
Changes
from a
positively
charged
Amino acid to
another
positively
charged
amino acid.
Pathogenic
S [Ser] ->
A [Arg]
Changes
from a Polar,
uncharged
Amino Acid to
a positively
charged
amino acid.
Pathogenic
G [Gly] ->
A [Ala]
Changes
from a
nonpolar
amino acid to
another
nonpolar
amino acid.
Pathogenic
Pathogenic
Pathogenic
2780T>C
Rs397508435
CTT ->
CCT
CUU ->
CCU
L [Leu] ->
P [Pro]
Changes
from a
nonpolar
amino acid to
a polar,
uncharged
Amino Acid.
3611G>C
Rs121908764
TGG ->
UGG ->
T [Trp] ->
Ends from an
From Genes to Genetic Diseases
DNA Research Paper
Ashtyn Brewster (AB10724)
2128A>T
1651G>A
3212A>C
Rs75115087
Rs121909013
Rs121909037
TAG
UAG
Stop
AAA ->
TAA
AAA ->
UAA
L [Lys] ->
Stop
Ends from a
positively
charged
amino acid.
Pathogenic
G [Gly] ->
S [Ser]
Changes
from a
nonpolar
amino acid to
a polar,
uncharged
amino acid.
Pathogenic
G [Gln] ->
P [Pro]
Changes
from a polar,
uncharged
amino acid to
another polar,
uncharged
amino acid.
Pathogenic
GGT ->
AGT
CAG ->
CCG
GGU ->
AGU
CAG ->
CCG
aromatic
amino acid.
b. Point mutations would have a lesser effect on the change of the amino acid sequence.
i. All of the non-pathogenic alleles have a point mutation.
c.
i. *found fasta sequence*
ii. The nucleotide would have a frame shift mutation or would stay the same.
Testing How the Mutation Matters
3b. I think some of the differences change the number of amino acids brought to the cell, creates
codons without complementary anti-codons, and changes the number of mRNA bases that make up the
codons.
3c. Non-pathogenic alleles do not disrupt the protein’s function because only one allele is changed.
From Genes to Genetic Diseases
DNA Research Paper
Ashtyn Brewster (AB10724)
Vocabulary:
Genes - the basic physical unit of heredity
DNA - an extremely long macromolecule that is the main component of
chromosomes and is the material that transfers genetic characteristics in all life
forms, constructed of two nucleotide strands coiled around each other in a
ladder-like arrangement with the sidepieces composed of alternating phosphate
and deoxyribose units and the rungs composed of the purine and pyrimidine
bases adenine, guanine, cytosine, and thymine
Mutation - a sudden departure from the parent type in one or more heritable
characteristics, caused by a change in a gene or a chromosome.
Genetic disease - A disease caused by the absence of a gene or by products of a
defective gene.
Nucleotides - any of a group of molecules that, when linked together, form the
building blocks of DNA or RNA.
RNA - ribonucleic acid: any of a class of single-stranded molecules transcribed
from DNA in the cell nucleus or in the mitochondrion or chloroplast, containing
along the strand a linear sequence of nucleotide bases that is complementary to
the DNA strand from which it is transcribed - to make an exact copy of (a
document, text, etc.).
Transcription – the act of making an exact copy of (a document, text, etc.).
Translation - the genetic code carried by mRNA is decoded to produce the specific
sequence of amino acids in a polypeptide chain
Amino acids - the building blocks from which proteins are constructed.
From Genes to Genetic Diseases
DNA Research Paper
Ashtyn Brewster (AB10724)
Codon - a triplet of adjacent nucleotides in the messenger RNA chain that codes
for a specific amino acid in the synthesis of a protein molecule.
Hydrophilic - having a strong affinity for water.
Hydrophobic - having little or no affinity for water.
Allele - any of several forms of a gene, usually arising through mutation, that are
responsible for hereditary variation.
Extra Questions:
How does a gene become a protein?
DNA creates mRNA to send to the ribosomes that read it, and converts it to three bases that turn into an
amino acid. A more complex packaging and Tertiary process occur in the Golgi Apparatus. The enzyme is
now ready for use.
In a given gene, what kind of DNA mutation would not change the protein that is made?
A silent mutation would not change the protein that is made.
What makes some amino acids hydrophobic and others hydrophilic?
When an amino acid is hydrophobic, the amino acids tend to go to the inside of a protein.
When an amino acid is hydrophilic, the amino acids tend to go to the outside of a protein.
How common are mutations in the human genome?
The mutation frequency is very low considering the human DNA can most likely correct itself.
Is it very likely or very unlikely that your DNA carries any mutations?
It is very unlikely that your body will carry any mutations.
From Genes to Genetic Diseases
DNA Research Paper
Ashtyn Brewster (AB10724)