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Lecture 6. altered genes are mutations

The DNA sequences from two individuals of the same species are highly similar - differing by only about one nucleotide in 1,000. A mutation is, most simply, an alteration in a DNA sequence.  This change may or may not lead to a change in the protein coded by the gene.  A change that has no effect on protein sequence or function is termed a polymorphism and is a part of the normal variation present in the human genome.  Often, however, a change in a DNA sequence will result in the disruption of gene function that we term "Clinical Manifestations" in the Clinical Integration Model .  The altered protein that results from a mutation can disrupt the way a gene functions, and this can lead to clinical disease.  How these mutations manifest themselves depends on each individual's unique genetic endowment and interactions with their environment. 

Furthermore, the change may or may not be passed on to subsequent generations.  If, as in non-familial cancer, the mutation occurs in isolated somatic cells , it will not be passed on to subsequent generations.  Only those mutations occurring to the DNA in the gametes (egg or sperm) will potentially be passed on to offspring.  If the mutation is passed on to the offspring, they will carry this mutation in all of the cells in their body.  

Following is a brief review of different types of mutations:

Base pair substitution

Replacement of one DNA base by another in the DNA sequence. Replacement of nucleotide bases can have several possible consequences.

Missense mutation

An amino acid residue in the original protein may be replaced by a different one in the mutated protein.

Nonsense mutation

The codon for an amino acid residue within the original protein is changed to a stop codon, which leads to a premature termination of the protein resulting in a non functional protein.

Silent mutation

  The codon for an amino acid is changed, but the same amino acid is still coded for.  This is possible because some amino acids are coded for by multiple codons.  For example, the sequences UGC and UGU both code for Cysteine.

Frameshift mutation

A deletion or insertion of any number of bases other than a multiple of three bases has a much more profound effect. Such frameshift mutation results in a complete change in the amino acid sequence downstream from the point of mutation, instead of simply a change in the number of amino acids.  

Deletions, insertions, and duplications

Deletions or insertions may be large or small. Large insertions and deletions in coding regions almost invariably prevent the production of useful proteins. The effect of short deletions or insertions depends on whether or not they involve multiples of three bases. If one, two, or more whole codons (three base pairs or any multiple of three) are removed or added, the consequence is the deletion or addition of a corresponding number of amino acid residues.  Sometimes, an entire gene can be inserted (duplicated) or deleted.  The effects of these types of mutations depend on where in the genome they occur and how many base pairs are involved.  

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
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Source:  OpenStax, Genetics. OpenStax CNX. Jul 29, 2009 Download for free at http://cnx.org/content/col10782/1.1
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