In March 2013, Mat and Bella are heading to Utrecht to for a conference about genetics education in the 21st century. A couple of similar conferences have taken place in the last few years – ‘Rethinking science curricula in the genomics era‘ and one with a longer title.
To prepare for the conference, we have been asked to answer these two questions:
- ‘What knowledge of genetics is relevant to those individuals not professionally involved in science?’ and
- ‘Why do you consider this knowledge relevant?’ .
A couple of interesting questions, so we thought we’d share our interesting answers:
What knowledge of genetics is relevant to those individuals not professionally involved in science?
- All cellular organisms have a genome – a complete set of instructions, encoded in the chemical DNA, for that organism to grow, develop and live
- Our genomes are inherited from our parents – 50% from each; if we have children, we pass on 50% of our genome to them
- DNA is a chemical made up of four constituent parts (nucleotides) that are abbreviated to A, T, C and G and can be considered DNA’s alphabet for writing the instructions it encodes
- Reading the letters of DNA is known as ‘sequencing’; we can sequence a genome in a couple of days
- A specific instruction is termed a ‘gene’ and it acts as a template to produce another chemical, usually a protein that performs a specific role; proteins help organisms grow, develop and work; genes and their products contribute to the physical characteristics of an organism
- Only a small fraction (<2%) of the genome is made of genes encoding proteins; much of the remainder is likely to have has some function in regulating the output of the protein-encoding genes
- Genes are regulated (turned on and off, and up and down) very carefully in cells; if genes are not carefully controlled it can lead to disease, including cancer in humans; there is a wide variety of regulatory mechanisms, which can respond to internal changes and environmental influences; epigenetic changes are a special type of regulation which overlie the genome; in some cases epigenetic changes can be inherited through generations
- Differences in single letters of the DNA alphabet are called ‘variants’ and occur naturally throughout the genome – apart from identical twins, no two individuals share identical genomes; there are at least 10 million variable sites in the human genome, so at least 3,000,000 differences between the genomes of any two individuals
- Variation between genomes (different genotypes) accounts for some of the physical variation (different phenotypes) within a population
- In humans, some gene variants (changes in the letters that spell out an instruction) can lead to health problems; usually a change in a gene does not actually cause disease, but it may lead to an increased (or decreased) likelihood of developing a condition (such as type 2 diabetes, or breast cancer); occasionally, gene variants do directly cause a disease by significantly changing or removing a protein, for example, cystic fibrosis or Huntington disease
- As well as influencing how likely we are to develop certain conditions, our genes can also affect our response to medicines; many future medicines could be developed around the idea of ‘pharamacogenetics’ – drugs that only work in people with a certain genetic make-up; by definition, such drugs would only be effective in a proportion (possibly a minority) of the population and not everyone would stand to benefit from them
- Both historically and in the future, knowledge of genetics has major ethical, legal and social implications
Why do you consider this knowledge as relevant?
The approach we are outlining above represents a departure from traditional teaching of genetics in UK schools. However, we feel this change is important given that the pace of research in this field is so high that we run the risk of failing to appropriately equip students with the knowledge and understanding they will need to make sense of the genetics they encounter in the world around them.
From our perspective as ‘a centre for genetics in healthcare’, in the future people are most likely to encounter genetics through a clinical setting or direct to consumer (DTC) genetic testing. The above points would be relevant to both these groups. DTC companies already offer genetic testing kits that analyse whole genomes for just a few hundred pounds/euros. The constantly falling cost of genome analysis, whether by SNP arrays or next generation sequencing technologies, means that people’s personal genomic information is going to become ever more accessible to them in the near future.
However, in spite of the hyperbole from some quarters, it is currently unclear what the value of this ‘whole genome’ information will be. Therefore, it is important that people are able to assess the value of a list of ‘facts’ about themselves relating to their likelihood of developing certain diseases throughout their lives. Such facts will be difficult to reconcile with their experience of genetics as taught in school, which is currently based around a simple model of deterministic dominant and recessive alleles. Furthermore, as the importance of non-coding DNA (as evidenced by the ENCODE project) is elucidated, it seems likely that non-coding variants will also affect our health through altering gene expression – focusing solely on protein-coding genes will fail to convey the importance of non-coding DNA and non-coding RNAs.
We believe there should be a shift away from genetics based on the transmission of genes and instead focus on sequence genomics – the sequence of DNA that underpins cellular organisms. Such an approach to genetics is fundamental and will not change.