Skip to 0 minutes and 0 seconds There are many different reasons why people want to look at genomes or genomic information, and it really depends, I suppose, on who is doing the asking and what question they might have. Researchers have always been interested, ever since they’ve known about genomic information, to learn more about what information is in a particular genome and what that means to the development of that particular organism. People working in healthcare they’re very interested in the genomic changes that can affect people’s health or how they react to different medications. And individuals themselves are very curious about their own genomes and what that means, either in terms of their own health or where their genomes actually came from.
Skip to 0 minutes and 37 seconds Since we’ve known about the sequence, say in human genomics about the whole human genome sequence following from the Human Genome Project, we have a greater understanding of what information is in our genome and now we’re asking very specific questions. In general what we’re looking for when we analyse a genome, in particular in healthcare, are changes that have occurred in that genome. So in a human genome we have 3.2 billion bases, these are the chemical letters that make up our DNA, and we’re looking for any changes that are there that are different from we call the reference genome. It’s estimated that we have about 0.2-0.1% differences, that’s 3 million changes that we’re looking at, which is actually quite large.
Skip to 1 minute and 20 seconds What’s important to know is not all of those changes are detrimental to health, so differences in height, differences in eye colour, differences in hair colour, etc, are all down to our genome. Some of these changes may be pathogenic, which means that they can be attributed to the condition that someone may have, or may mean that someone is more likely to develop that condition in the future. Other changes, they will be called benign changes, which means that it has no effect on their health at all, but it may be the cause of this natural variation that we’re seeing between us.
Why do we want to know about genomes?
Before we start looking in more detail at the genome and what it means for our health, Dr Michelle Bishop, one of our course educators, introduces us to a range of reasons why different people and professions want to know about genomes.
- why scientists have been driven to find out more about genomes;
- why healthcare professionals might make increasing use of information about a person’s genome in healthcare; and
- why individuals are choosing to learn more about their genetic make-up.
Michelle explains that:
- there are around 3.2 billion chemical letters in the human genome and around 99.9% of our genome is identical to other people’s;
- in healthcare we are focused on the relatively small number (approximately 3 million) of changes or variants present in an individual genome. We will explore what we mean by DNA changes/variants later this week;
- not all variation is bad. Variation in the genome is responsible for the natural variation we see between us - for example eye colour and hair colour - but sometimes this variation can be ‘pathogentic’ (disease-causing). This is the focus of genomic analysis in healthcare.
Michelle introduces a few words and terms in this film, such as ‘bases’ and ‘reference genome’, which you may not be familiar with; please don’t worry, these will be clarified as you move through the course and begin to learn more about how genomics - and whole genome sequencing specifically - is used to help patients.
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