Mutation
Gene Mutation
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Chromosome Mutation
Definition: Chromosome structure mutations are alterations that affect whole chromosomes and whole genes rather than just individual nucleotides. These mutations result from errors in cell division that cause a section of a chromosome to break off, be duplicated or move onto another chromosome.
A genetic mutation is a change in a sequence of the DNA. The DNA sequence gives cells the information they need to perform their functions. Some mutations can lead to genetic disorders or illnesses.
Cause
Short definition: a chromosome mutation affects the chromosome and genes as a whole. This mutation creates irregular chromosome patterns which can end up in the wrong places or go through the wrong process.
Genetic mutations may occur during cell division when cells divide and replicate. There are two types of cell division:
Mitosis: The process of making new cells for your body. During mitosis, your genes instruct your cells to split into two by making a copy of your chromosomes.
Meiosis: The process of making egg and sperm cells for the next generation. During meiosis, chromosomes copy themselves with half the amount of chromosomes as the original (from 46 to 23). That’s how you’re able to get your genetic material equally from each parent.
Error in DNA replication: When a cell divides, a copy of DNA is made. However, not every copy of DNA is perfect and a small difference occur. This causes mutation. The more cell divisions there are, the higher chance of errors happening in DNA replication.
Fail in repairation: When a DNA is damaged, a cell would try to repair it or put the strand back together. However, it is possible for the cell to mistakenly substitute the genetic letter. This leads to mutation.
External cause: Heat, radiation or specific chemicals known as mutagens (such as UV light) can damage or cause changes to the covalent bonds between nitrogenous bases in DNA.
Cell division
Genetic mutations occur during cell division. When your cells divide, they hand-write your body’s instruction manual by copying the original document word for word. There’s a lot of room for error during cell division because your cells might substitute (replace), delete (remove) or insert (add) letters while they’re copying. If you have an error (genetic mutation), your genetic instruction manual for your cells may not be readable by the cells, or may have missing parts or unnecessary parts added. All of this can mean that your cells can’t function as they normally should.
Genetic mutations affect other organs.
Cause
A chromosomal mutation happens because of a change in chromosome structures, chromosomal rearrangement, or other chromosomal abnormalities such as a change in chromosome number or missing chromosome.
A genetic mutation changes the information your cells need to form and function. Your genes are responsible for making proteins that tell your body what physical characteristics you should have. If you have a genetic mutation, you could experience symptoms of a genetic condition because your cells are doing a different job than they should be. Symptoms of genetic conditions depend on which gene has a mutation. There are many different diseases and conditions caused by mutations. The signs and symptoms you experience could include:
Physical characteristics like facial abnormalities, a cleft palate, webbed fingers and toes, or short stature.
Problems with cognitive (intellectual) function and developmental delays.
Vision or hearing loss.
Breathing problems.
Increased risk of developing cancer.
Types of chromosome mutation
Inversion: its segments are reversed from end to end.
Some genetic mutations even have a positive effect on humans. Changes in how cells work can sometimes improve the proteins that your cells produce and allow them to adapt to changes in your environment.
An example of a positive genetic mutation is one that can protect a person from acquiring heart disease or diabetes, even with a history of smoking or being overweight.
Mutation I consists of inversion, deletion, duplication, and translocation
We can inherit germline genetic mutations. There are several patterns that genetic mutations can pass from the parent to a child (hereditary) :
Deletion: Also known as partial monosomies, these occur when a piece of a chromosome accidentally gets removed or deleted.
Duplication: an extra copy of a segment or the entire chromosome is present in the nucleus. These are also known as partial trisomies.
Translocation: Translocation chromosomal mutation follows the route of biological translocation. This happens when a segment of a chromosome breaks off and then relocates to a completely different chromosome. This creates fusion chromosomes as one type of chromosome fuses with another.
Autosomal dominant.
Only one parent needs to pass the genetic mutation onto their child for their child to inherit the mutation.
Example of it is marfan syndrome
Autosomal recessive.
Both parents need to pass the same genetic mutation onto their child for their child to inherit the mutation.
Example of this is Sickle cell disease
X-linked.
Babies assigned male or female have an X chromosome. Mutations on the X chromosome can pass in a dominant or recessive pattern, but not every pattern is clear on how the child acquired the mutation from their parents.
Example of it is Thrombocytopenia
Y-linked.
Only babies assigned male at birth have a Y chromosome and can inherit this type. Only one mutation on the Y chromosome needs to pass to the child to inherit the mutation.
Example of it is Webbed feet
Chromosome abnormality: Changes in chromosome structure and abnormality in chromosome numbers.
Codominant.
Each gene has two parts (one from the egg and one from the sperm). They usually work together to create a single trait. But sometimes, they each work separately to produce variations of the trait.
Example of it is Alpha-1 antitrypsin deficiency
Aneuploidy: This mutation either causes the loss or addition of a chromosome by the contortion of the chromosome set. Nondisjunction during meiosis or mitosis usually results in this mutation.
Mutation II aneuploidy and polyploidy
Process mistakes: Mistakes in crossing over or chromosome division can cause mutation.
Lagging in division phase: If some portions of chromosomes "lag" in anaphase, they could be lost during the nuclei reorganization phase (Telophase)
Polyploidy: This mutation causes the creation of two sets of genomes within an organism. It is not usually common naturally however, it can be observed in some plants. It usually causes effects like giantism and the reduction of fertility
External cause: Heat, radiation or specific chemicals known as mutagens (such as UV light) can damage or cause changes to the covalent bonds between nitrogenous bases in DNA.
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