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Heredity: Genetic Mutations

Heredity involves the transmission of genetic characters from parents to offspring through the segregation and recombination of genes during meiosis and fertilization, resulting in offspring that are similar to others of their kind but also exhibit some variations from the particular mix of genes and their interaction with the environment. Genetic mutations can occur through changes in DNA base pairs, such as substitutions, insertions, deletions, duplications, frameshifts, and repeat expansions, and can alter the resulting protein's function.

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48 views2 pages

Heredity: Genetic Mutations

Heredity involves the transmission of genetic characters from parents to offspring through the segregation and recombination of genes during meiosis and fertilization, resulting in offspring that are similar to others of their kind but also exhibit some variations from the particular mix of genes and their interaction with the environment. Genetic mutations can occur through changes in DNA base pairs, such as substitutions, insertions, deletions, duplications, frameshifts, and repeat expansions, and can alter the resulting protein's function.

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AgronaSlaughter
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© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Heredity

The transmission of genetic characters from parents to offspring: it is dependent upon the
segregation and recombination of genes during meiosis and fertilization and results in the genesis
of a new individual similar to others of its kind but exhibiting certain variations resulting from
the particular mix of genes and their interactions with the environment.
the genetic characters so transmitted.

Genetic Mutations
This type of mutation is a change in one DNA base pair that results in the
substitution of one amino acid for another in the protein made by a gene.

Nonsense mutation (illustration)

A nonsense mutation is also a change in one DNA base pair. Instead of substituting
one amino acid for another, however, the altered DNA sequence prematurely
signals the cell to stop building a protein. This type of mutation results in a
shortened protein that may function improperly or not at all.

Insertion (illustration)

An insertion changes the number of DNA bases in a gene by adding a piece of DNA.
As a result, the protein made by the gene may not function properly.

Deletion (illustration)

A deletion changes the number of DNA bases by removing a piece of DNA. Small
deletions may remove one or a few base pairs within a gene, while larger deletions
can remove an entire gene or several neighboring genes. The deleted DNA may
alter the function of the resulting protein(s).

Duplication (illustration)

A duplication consists of a piece of DNA that is abnormally copied one or more


times. This type of mutation may alter the function of the resulting protein.

Frameshift mutation (illustration)


This type of mutation occurs when the addition or loss of DNA bases changes a
gene's reading frame. A reading frame consists of groups of 3 bases that each code
for one amino acid. A frameshift mutation shifts the grouping of these bases and
changes the code for amino acids. The resulting protein is usually nonfunctional.
Insertions, deletions, and duplications can all be frameshift mutations.

Repeat expansion (illustration)


Nucleotide repeats are short DNA sequences that are repeated a number of times in
a row. For example, a trinucleotide repeat is made up of 3-base-pair sequences, and
a tetranucleotide repeat is made up of 4-base-pair sequences. A repeat expansion is
a mutation that increases the number of times that the short DNA sequence is
repeated. This type of mutation can cause the resulting protein to function
improperly.

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