Genetic variants in non-coding DNA can influence phenotype
Lesson details
Learning outcome
I can explain how a genetic variant in a non-coding part of the genome can influence an organism’s phenotype.
Key learning points
- When a cell copies a gene to make mRNA (the instructions to make a protein), this is called gene expression.
- Only around 1-2% of the genome is genes; the rest contains code that controls gene expression.
- A genetic variant in a non-gene (so called "non-coding") section of the genome can affect gene expression.
- Non-coding DNA affects gene expression because it is where RNA polymerase starts copying the gene for protein synthesis.
- Genetic variants in non-coding DNA can impact gene expression and therefore an organism’s phenotype.
Keywords
Gene - A section of DNA that holds the genetic code for a protein.
Protein - A chemical substance whose structure is coded for by the genetic code in genes.
Gene expression - The process in which genes are copied during the first step in protein synthesis.
Genetic variant - Produced when a mutation causes a change in the genetic sequence of a gene or non-coding section of DNA.
Phenotype - The physical characteristics of an organism.
Common misconception
All DNA is genes that code for proteins; and that our characteristics are only affected by our genes
Most of the DNA is non-coding (non-genes), and controls when genes are expressed (i.e. when proteins are made). Changes (genetic variants) in non-coding DNA can affect characteristics (phenotype) as they control whether a gene is expressed or not.
Teacher tip
Edit this slide deck dependant on exam board and ability. There is opportunity to research the role of epigenetics and new treatments for diseases once pupils understand that the expression of genes can be changed even though the base sequence within the genes stays the same.
Equipment
None required.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Match each word to its correct meaning.
Something capable of causing a change in the genetic code.
A change in the genetic code.
The process of copying a gene and making mRNA.
Using the genetic code of mRNA to make a polypeptide.
Q2.Match the number to the description.
The number of types of nucleotide base in DNA.
The number of nucleic acid strands in a molecule of DNA.
The number of nucleic acid strands in a molecule of mRNA.
The number of nucleotide bases in a triplet code.
Q3.Which of these is not a type of mutation?
Q4.Allele 1 has mutated to become allele 2.
Allele 1 code: ATT CCG GAC TAT ATA CGC CCC.
Allele 2 code: ATT CGG GAC TAT TAT ACG CCC C.
How many mutations have there been in allele 1
Q5.Put the statements in order to describe how a gene in the nucleus is used to make an enzyme that controls a chemical reaction in the cytoplasm.
Q6.A change in the 3D structure of a protein may lead to a change in an organism such as a different eye colour. What word do biologists use for physical characteristics such as eye colour?
Assessment exit quiz
6 Questions
Q1.Genes are instructions to a cell on how to produce which type of molecule?
Q2.DNA that isn’t used to determine the structure of a protein is called DNA.
Q3.What does the term 'gene expression' mean?
Q4.Put the events in the synthesis of a protein in the correct order.
Q5.Changes to the non-coding DNA nucleotide sequence can happen due to copying errors or because of environmental factors such as chemicals in cigarette smoke. What are these changes to the DNA called?
Q6.There are several ways changes to non-coding DNA can affect an organism's phenotype. Match the change to the description of how it can alter phenotype.
Cells constantly grow and divide leading to tumour formation.
Transcription is prevented and the protein can’t be produced.
Gene remains inactive and protein is not produced.
To help you plan your 10 biology lesson on: Genetic variants in non-coding DNA can influence phenotype, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 10 biology lesson on: Genetic variants in non-coding DNA can influence phenotype, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 4 biology lessons from the DNA and the genome unit, dive into the full secondary biology curriculum, or learn more about lesson planning.