BIO 10 - Module 3 Topic 5

Gene Regulation and Biotechnology

True or False: All DNA actually makes “stuff”

FALSE: Not all of our DNA actually makes “stuff”

What are coding regions?

Exons

What are non-coding regions?

Introns

What DNA regions do not code for proteins?

75% of noncoding DNA occurs between genes, while 25%, called introns, occur within genes

What mechanisms change DNA sequence and organismal function?

1. Mutation

2. DNA Shuffling

3. Horizontal Gene Transfer

4. DNA Gains and Losses Over Time (segway to evolution)

What is the most common error source and how often?

DNA mutation — an average mistake of 1 base pair every 10,000

What declines the rate of DNA mutation to 1 every 1,000,000,000?

proofreading and repair mechanisms

What generates the highest potential impact on the population?

“mistakes” during meiosis — the assortment and cross-over events that impact gene expression

How impactful is mutation?

it can range from small to large

What is DNA mutation?

a change in sequence, or the loss or gain in DNA

How high are the rates of mutation?

extremely low

What is mutation an essential component of?

evolutionary change

What is the most common source of DNA mutation?

error during DNA replication and meiosis

How can DNA mutation be avoided?

cells have DNA repair mechanisms to combat this

True or False: Environmental damage to the DNA can cause mutation

True

When can mutation happen?

1. DNA replication (DNA → DNA)

2. DNA → RNA

3. RNA → protein

Is mutation intentional?

No, it is an accidental change in the sequence

What is the most common source of DNA mutation?

DNA replication

In what ways can single-pair DNA mutations alter protein expression?

1. Silent Mutation

2. Nonsense Mutation

3. Missense Mutation

4. Frameshift Mutation

What is the effect of silent mutation?

there is no effect on the amino acid produced because of redundancy into the Genetic Code

What is the effect of nonsense mutation?

it changes an amino acid codon into a stop codon

What is the effect of missense mutation?

It is still code for an amino acid, but not necessarily the right one

What is effect of frameshift mutation?

results from the insertion or deletion of nucleotides that alter the reading frame

What can DNA shuffling during meiosis do?

it can add or subtract smaller pieces of DNA to a gene

What are the benefits and risks of DNA shuffling?

• incomplete or partial cross-over events

• pieces of different genes can be combined to form new genes with hybrid functions

• it can introduce new combinations of gene sequences into every new generation for evolution

• it can break up “good combinations” that have been generated

When does Horizontal Gene Transfer (HGT) occur?

occurs when genes are transferred directly between organisms, in the lab and in nature

Who can share their genetic codes?

any two major groups of organisms — including humans

Why is HGT an important mechanism?

• spread of antibiotic resistance in bacteria

• evolution of bacteria that can degrade pesticides

• evolution and transmission of virulence factors/viruses

How do genomes compare?

Not all are created equal

How does translation compare among organisms?

it varies

What does non-coding DNA do?

alternative splicing

What is biotechnology?

the use of organisms to make useful products?

What methods utilize or modify organisms to satisfy human needs with biotechnology?

1. Selective breeding — food and others

2. Cellular fermentation products — food and drinks

3. Generic engineering — medicine and food

How did selective breeding start?

Agriculture — using organisms for our needs

What was the earliest biotech enterprise?

domestication of plants and animals (>12,000 years ago)

What did early agriculture do?

• provided controllable means to get food

• early farmers selected and bred crops with the best yield

• allowed humans to settle in place

What are some derivatives of the wild mustard plant?

• kale

• broccoli

• brussels sprouts

• cabbage

• cauliflower

How does cellular fermentation work?

Use of metabolic process (fermentation) to make products — glycose → pyruvate (no oxygen → fermentation) → Aspergillus, Lactobacillus, Saccharomyces

What are the products of fermentation?

acids, gases and alcohol are the (waste) products

What is an example of Aspergillus?

soy sauce

What is are some examples of lactobacillus?

cheese and yogurt

What are some examples of saccharomyces?

beer, wine, and bread

What is an example of genetic engineering?

Genetically Modified (GM) organisms

What is the aim for genetic engineering in genetically modified crops?

to introduce traits that did not exist in the original plant

What are some examples of genetically modifications?

• resistance to pests, weeds, disease, and harsh environments

• reduction of spoilage, better flavor/nutrition value

Name one specific example of beneficial genetic engineering?

Bacillus thuringiensis (Bt) Corn

• insects that eat Bt toxin are killed within a couple days

• the crystal toxin genes have been cloned from the bacterium and introduced into plants

  • allows plants to produce their own Bt that acts against insects

How does Bt toxin affect the environment and mammals

it has been pronounced safe for the environment and mammals — approved for organic farming

What is a concern regarding the Bt toxin?

insects may evolve resistance to the Bt toxin

What are the ethical considerations of genetic modification?

• financial gain can over-rule moral considerations

• there is big money behind curing disease and eliminating gene defects

How difficult is changing genes and genetics?

it is relatively easy