Chromosome Mutations – II
Mutations involving changes in the nucleotide
Reviewed by: Mary Anne Clark, Ph.D.
This page is a continuation of the previous tutorial, Chromosome Mutations – I.
Alteration of a DNA Sequence
The previous examples of mutation have investigated changes at the chromosome level. The sequence of nucleotides on a DNA sequence are also susceptible to mutation.
- Deletion
Here, certain nucleotides are deleted, which affects the coding of proteins that use this DNA sequence. If for example, a gene coded for alanine, with a genetic sequence of C-G-G, and the cytosine nucleotide was deleted, then the alanine amino acid would not be able to be created, and any other amino acids that are supposed to be coded from this DNA sequence will also be unable to be produced because each successive nucleotide after the deleted nucleotide will be out of place. - Insertion
Similar to the effects of deletion, where a nucleotide is inserted into a genetic sequence and therefore alters the chain thereafter. This alteration of a nucleotide sequence is known as frameshift - Inversion
Where a particular nucleotide sequence is reversed, and is not as serious as the above mutations. This is because the nucleotides that have been reversed in order only affect a small portion of the sequence at large - Substitution
A certain nucleotide is replaced with another, which will affect any amino acid to be synthesized from this sequence due to this change. If the gene is essential, i.e. for the coding of hemoglobin then the effects are serious, and organisms in this instance suffer from a condition called sickle cell anemia.
All of the genetic mutations looked at through the last 2 pages more or less have a negative impact and are undesired, however, in some cases they can prove advantageous.
Genetic mutations increase genetic diversity and therefore have an important part to play. They are also the reason many people inherit diseases.
The next tutorial looks at the mutation at the gene level.
 | CHROMOSOMAL MUTATION MATCH-UP ACTIVITY A critical-thinking match-up activity on chromosomal mutation! This matching-type test is useful in tracking the student’s skills in recognizing the different kinds of chromosomal mutations. Subjects: Genetics & Evolution |
You will also like...
Temperature Regulation in Animals
This tutorial elucidates body temperature regulation. Know the details here to learn how the body sets the body temperat..
Still Water Animals
Animals living in aquatic habitats have diversified and evolved through time. They eventually occupy ecological niches a..
Growth Patterns
This tutorial describes the sigmoid curve, annual plant growth, tree growth, human growth, and insect growth as the grow..
Freshwater Ecology
Freshwater ecology focuses on the relations of aquatic organisms to their freshwater habitats. There are two forms of co..
Freshwater Community Energy Relationships – Producers & Consumers
This tutorial looks at the relationship between organisms. It also explores how energy is passed on in the food chain an..
Abiotic and Biotic Factors
This tutorial deals with the abiotic factors of the freshwater environment that determine what sort of life would be sui..