Hey there!
I’m Vanessa and you’re just in time, take a seat.
Because I have a story and it begins in Australia, on the island of Tasmania.
This is where biologist Elizabeth Blackburn was born and raised.
“Hello!
My name’s Elizabeth Blackburn.”
She grew up to study biology at the smallest scale–in molecules and cells–using one
of Earth’s smallest creatures: tetrahymena.
Liz had no idea these creatures might hold clues to our health.
Inside our cells, genes are arranged on chromosomes, ladders of DNA that hold instructions for
the building blocks that built you.
To keep the cell from thinking chromosome ends are broken DNA, they have special caps
called telomeres, kind of like the plastic tip at the end of your shoelaces.
Each time your DNA is copied and a cell divides, the telomeres get shorter, until a cell either
dies or stops dividing forever.
But tetrahymena can divide forever, their telomere caps don’t wear down.
By watching these tiny creatures grow, Liz Blackburn and Carol Greider discovered telomerase,
an enzyme that adds new DNA to the ends of telomeres.
Liz and Carol’s discovery of telomerase was so groundbreaking, they won a Nobel Prize.
Humans have telomerase in our cells too!
But mature cell types are very reluctant to let their telomerase act, they kind of keep
it switched off.
As a result, telomeres keep shortening and have been called a “molecular clock”…
As our lives progress, our telomeres get shorter… and that shortening is linked to just about
every major disease of aging.
Scientists thought maybe they could switch on telomerase… if it kept our telomeres
long, our cells might never die, and maybe neither would we.
Telomerase could even be the key to immortality…
But can you really manipulate your cells so you never age?
Recently, scientists found increasing the length of telomeres in lab-grown human cells
made the cells behave like they were much younger.
But telomerase is a double-edged sword.
When we coax cells to overproduce telomerase, they can more easily become cancerous.
In reality, aging is pretty complicated.
The idea that the length of our life is programed in our cells is just one theory to explain
it.
Do shorter telomeres cause aging?
Or does aging cause shorter telomeres?
Both are true, but we don't know which one actually matters in human lives.
What we do know is that normal cell growth isn’t the only influence on telomere length.
Liz and other scientists have found that heredity, chronic stress, domestic violence, depression,
and even consumption of sugar-sweetened beverages are all linked to shortened telomeres.
Telomeres that are too short make us age badly, because they can push the effects of aging
to pile up more quickly.
Even if we could manipulate our cells to be immortal, we’d still have to reverse the
effects of our environment and behaviour.
The effects of our, and others, behaviour and choices can affect us on a cellular level.
Perhaps, theoretically, science could save us from aging.
But can we save us from ourselves?
There are many aspects about being a scientist that are tremendously rewarding, but I'm a
little bit addicted to it.
And I think this is because biology is just extraordinarily interesting, you know.
The complexities, the interesting ways that problems get solved at a molecular and cellular
and organismal level and the level of the brain, is just amazing.