Back to: MICROBIOLOGY 200 LEVEL
Welcome to class!
Welcome back, superstar! It’s always a joy to have you here. You’re doing so well, and your dedication is what will make you stand out as a future scientist and problem solver. Today’s topic is one that connects everything we’ve been learning so far — how genes change and how those changes shape entire species over time. Let’s look at the Role in Genome Evolution and Mutation and break it down into something simple and very real.
Role In Genome Evolution And Mutation
Have you ever looked at an old family album and noticed how your parents, grandparents, and even siblings have little differences — maybe a different nose shape, skin tone, or height? These differences come from mutations and changes in the genome (the complete set of DNA in an organism). Over time, as these changes build up, they lead to evolution — slow but steady improvements or adaptations that help organisms survive.
In microorganisms like bacteria, these changes happen quickly and often, helping them survive harsh environments, like antibiotics. Let’s see how it all works.
What is Mutation?
A mutation is a change in the DNA sequence.
It can happen naturally during DNA replication or due to external factors (mutagens).
Mutations can be beneficial, harmful, or neutral.
Types of Mutations:
Point mutation: A single base in DNA is changed (like changing one letter in a word).
Insertion: Extra DNA is added.
Deletion: A piece of DNA is removed.
Sometimes, these mutations don’t affect the organism at all. Other times, they can make bacteria resistant to antibiotics or allow them to use new food sources.
What is Genome Evolution?
Genome evolution is how the structure and size of the DNA in an organism changes over generations.
This can happen through:
Mutations
Gene duplications
Horizontal gene transfer (transformation, transduction, conjugation)
Mobile genetic elements (like transposons)
How They Are Connected
Mutations create small, random changes.
If a mutation is helpful (like resistance to heat or antibiotics), it is kept and passed on.
Over time, many of these changes add up, leading to new traits, behaviours, or even new species.
In Bacteria:
Evolution happens very fast because they reproduce quickly.
A single mutation can help a bacterium survive a drug — and that gene spreads to others.
Real-Life Example
The rise of multi-drug resistant tuberculosis (MDR-TB) is an example of genome evolution. Mutations allowed the bacteria to resist antibiotics. Now, newer drugs are needed to treat these stronger strains.
Summary
- Mutations are changes in DNA that can affect how organisms live and grow.
- They can be caused by replication errors or environmental factors.
- Mutations fuel genome evolution, which is the long-term change in an organism’s DNA.
- In bacteria, evolution happens fast, helping them adapt to new environments.
- Mutation and genome evolution are key to survival, resistance, and diversity.
Evaluation
- What is a mutation and how does it occur?
- Mention two types of mutations and explain them.
- How do mutations contribute to genome evolution?
- Give an example of a disease that shows bacterial evolution in action.
- Why do bacteria evolve faster than humans?
You’ve done wonderfully today. Understanding mutation and genome evolution is a big step toward mastering how life adapts and survives. Keep this up and you’ll be equipped to solve real-world health and environmental problems. Remember, Afrilearn is here with you, every step of the way. See you in the next exciting class!