Understanding Genes

My name is Julia Covas, I'm professor of genetics and psychology

at Goldsmiths University of London.

My own research is dedicated to understanding individual differences.

I'm interested in why people differ in their mind and behaviour.

And this course is exactly about this. This question.

We're going to talk about genes, mental health

and development.

So these are really big concepts, and in this course,

we're going to try and link them together.

So in the first session, uh, the first in the first lecture we're going to cover.

Um, just a simple question. What are jeans?

What do we mean by genes or genetic effects?

We will then talk about how genes

interplay or interact with environments

to affect our behaviour.

The third session will be about mental health.

So we're going to ask a question how genes and

the environment affect our mental health and in turn,

how mental health contributes to our development.

We will then look at the specific example of interplay between mental health,

a personality, characteristics and life outcomes such as, for example,

academic achievement.

And finally, we will talk about this really big concept of living in the genomic era.

So today we live in the era of genome,

where we're beginning to understand better and

better how genes contribute to our behaviour,

our mind and our development.

So we will start with the first

question,

what? Our genes.

So this question maybe, like really biological.

And, uh, you know,

one might wonder why Why do we want to go

into such biological concept if we're talking about psychology?

But I think it is really important to

always remember that humans are biological systems.

We have DNA

that makes us humans.

We have this this amazing kind of structure that

I will mention a few more words about,

um DNA,

which we have in every cell of our body

drives the development of our organism and in particular,

in psychology, we're interested in the brain.

So, uh, DNA affects the development of the brain. The brain is a really unique organ.

We think that it's the most complex object in the universe.

So the complexity of our brain is really mild, mind boggling.

So we have d n A.

We have the brain, we have other aspects of our organism,

all of which creates a biological system that in turn,

creates the mind So when we talk about psychological concepts, uh,

concepts that are related to the mind,

So they are a product of our biological system.

But what is really remarkable is that in turn, the mind

affects the biological system that we have.

So the way we think how we feel, what we are experiencing affects in turn, um,

and our biology, including how our genes work.

So it really is a complex, intricate system.

But going back to the question, What are genes?

Well, usually, when people talk about genes,

they think, or maybe remember from biology from school biology.

The genes are these segments of DNA that fulfil a particular function.

They code for protein.

So and then protein is a building block of many things, uh, in our body.

But actually, when we talk about genetic effects on development,

what we were talking about is not just genes, but DNA as a whole.

So human D N.

A is a very long sequence of amino acids, but I will leave it to biology kind of.

We're not going into that we're not going to talk about in this

course about nucleotides or amino acids or proteins or other biological concepts.

I would like to introduce DNA as a kind of at a conceptual level. So D n A is a text.

It's a meaningful sequence of letters nucleotides.

We have a very long sequence of letters, so we have approximately three billion

letters in the sequence, and this is this constitutes our whole whole of our DNA.

So these three billion letters in the sequence sit in

every cell of our body almost in every cell,

so that constitutes a lot of material.

But what is particularly interesting is that the Sikh, like with any text,

the sequence of letters or the sequence of nucleotides carries the meaning.

So the whole of our d. N A.

Is involved in somehow involved in our creating of our organism and in psychology,

we're interested in the mind.

Until very recently, we believed,

actually that only about 2% of our DNA sequence was meaningful,

So this was traditionally referred to as jeans.

So people believed that actually, most of our DNA doesn't do anything.

It was even called junk DNA.

But today we really understood

that DNA that is not

protein coding sequences. So not jeans

nevertheless fulfil some kind of functions.

We just don't understand them very well yet.

So today we refer to our DNA as coding parts of D N A,

which are traditionally known as genes.

So genes code for proteins

and most of our DNA is non coding DNA.

So this is the rest of the sequence,

which does not code for protein but seems to fulfil various other functions.

For example, non coding DNA may regulate

the workings of the genes.

So we have coding and non coding DNA.

None of it is junk.

Today we know that DNA as a whole seems

to be very important and fulfils various functions,

some of which we already understand and some we don't.

So, um, the kind of the big discoveries around about genetics have been, um,

completed at the beginning of the 21st century, where we now live.

So, for example,

the human genome for the first time was

sequenced at the beginning of the 21st century,

and today we're beginning to accumulate more

and more information about how genes work.

But for this particular course, I'd like to introduce another very,

very important concept.

So, so far, we've been talking about human DNA so as a whole.

And you probably know that humans share a lot of genetic material.

All of us all humans are approximately 99.9% identical in the genomic code.

So what does it mean? It means that if Johnny, if DNA is a text,

if we were reading one person's text and

then another person's text and another person's text,

we would actually be reading practically identical text.

So we are so similar. So the sequence of our amino acids in our DNA is identical,

but nevertheless, some of our DNA is not identical.

And these these points in our DNA sequence,

where different people can have different variants or alleles as they're called,

are called polymorphisms.

So these locations in DNA where people can differ are called polymorphisms.

So polymorphism is a very,

very important concept because it is when we

talk about genetic contribution to individual differences.

We actually talk about polymorphisms in our DNA,

so we will come back to this a little bit later in the course.

But this concept is very important to grasp.

So when we talk about, for example,

why do some people experience problems with mental health and other people don't.

Or why do some people run faster than other people?

Or why some people have motivations to do one

thing and other people motivations to do another.

So all of these human behaviours are partly influenced by genes,

and differences between people emerge because of

these polymorphic locations in the DNA.

So

the

when we talk about individual differences and referring to genetic differences,

that's what we're talking about polymorphisms.

So

to conclude this part of the of the course,

I'd like to summarise some key concepts when we

talk about genetic effects on behaviour on thought on,

uh, differences between people,

we refer to the whole of the D N A rather than just jeans

and specifically when we explain individual differences between people were

talking about specific locations in DNA where people can differ.

These locations are referred to as polymorphisms.

We have many polymorphisms in our DNA.

Several million

locations in the DNA have already been identified

that we refer to as polymorphisms.

That means that potentially

millions

of DNA markers, or polymorphisms,

contribute

to complex human characteristics that we will be discussing in the following

session