The secret of the bat genome Emma Teeling
what I want you all to do right now is
to think of this mammal that I’m going
to describe to you the first thing I’m
going to tell you about this mammal is
that it is essential for our ecosystems
to function correctly if we remove this
mammal from our ecosystems they simply
will not work that’s the first thing the
second thing is that due to the unique
sensory abilities of this mammal if we
study this mammal we’re going to get
great insight into our diseases of the
senses such as blindness and deafness
and the third really intriguing aspect
of this mammal is that I fully believe
that the secret of everlasting youth
lies deep within its DNA so are you all
thinking so magnificent creature isn’t
it
who here thought of a bat I can see half
the audience agrees with me and I have a
lot of work to do to convince the rest
of you so I have had the good fortune
for the past 20 years to study these
fascinating and beautiful mammals
one-fifth of all living mammals is a bat
and they have very unique attributes
bats as we know them have been around on
this planet for about 64 million years
one of the most unique things that bats
do as a mammal is that they fly now
flight is an inherently difficult thing
flight within vertebrates has only
involved three times once in the bat
once in the bird and once in the
pterodactyls and so with flight it’s
very metabolically costly bat have
learned and evolved how to deal with
this but one other extremely unique
thing about bats is that they are able
to use sound to perceive their
environment they
use echolocation now what I mean by
echolocation the emitter sound from
their larynx out to their mouth or
through their nose this sound wave comes
out and it reflects and echoes back of
objects in their environment and the
bats then hear these echoes and they
turn this information into an acoustic
image and this enables them to orient in
complete darkness indeed they do look
very strange we’re humans we are visual
species when scientists first realized
that bats are actually using sound to be
able to fly in orient and move at night
we didn’t believe it for a hundred years
despite evidence to show that this is
what they were doing we didn’t believe
it now if you look at this bat it looks
a little bit alien indeed the very
famous philosopher Thomas Nagel once
said to truly experience an alien life
form on this planet you should lock
yourself inside a room with flying at
locating bat in complete darkness and if
you look at the actual physical
characteristics on the face of this
beautiful horseshoe bat you see a lot of
these characteristics are dedicated to
be able to make sound and perceive it
very big ears strange nose leaves but
teeny tiny eyes so again if you just
look at this bat you realize sound is
very important for its survival most
bats look like the previous one however
there are a group that do not use
echolocation they do not perceive their
environments using sound and these are
the flying foxes if anybody has ever
been lucky enough to be in Australia
you’ve seen them coming out of the
Botanic Gardens in Sydney and if you
just look at their face you can see
they’ve much much larger eyes and much
smaller ears so among and within bats is
a huge variation in their ability to use
sensory perception now this is going to
be important for what I’m going to tell
you later during the talk now if the
idea of bats in your belfry terrifies
you and I know some people probably
are feeling a little sick looking at
very large images of bats that’s
probably not that surprising because
here in Western culture bats have been
demonized really of course the famous
book Dracula written by a fellow
Northside Dubliner Bram Stoker probably
is mainly responsible for this however I
also think it’s got to do with the fact
that bats come out at night and we don’t
really understand them were a little
frightened by things I can perceive the
world slightly differently than us bats
are usually synonymous from some type of
evil events they are the perpetrators in
horror movies such as this famous
Nightwing also if you think about it
demons always have bat wings whereas
bird they typically or angels have bird
wings now this is Western society and
what I hope to do tonight is to convince
you of the Chinese traditional culture
that they perceive bats as creatures
that bring good luck
and indeed if you walk into a Chinese
home you may see an image such as this
this is considered the five blessings
the Chinese word for bat sounds like the
Chinese word for happiness and they
believe that bats bring wealth health
longevity virtue and serenity and indeed
in this image you have a picture of
longevity surrounded by five bats and
what I want to do tonight is to talk to
you and to show you that at least three
of these blessings are definitely
represented by a bat and that if we
study bats we will get nearer to getting
each of these blessings so well how can
a bat possibly bring us wealth and as I
said before bats are essential for our
ecosystems to function correctly and why
is this bats in the tropics are major
pollinators of many plants they also
feed on fruit and they disperse the
seeds of these fruits bats are
responsible for pollinating the tequila
plant and this is a multi-million dollar
industry in Mexico so indeed we need
them for our ecosystems to function
properly
without them it’s going to be a problem
but most bats are ferocious insect
predators it’s been estimated in the US
and a tiny colony of big brown rats that
they will feed on over a million insects
a year and in the United States of
America right now bats have been
threatened by disease known as white
nose syndrome it’s working its way
slowly across the u.s. and wiping out
populations of bats and scientists have
estimated that 1300 metric tons of
insects a year are now remaining in the
ecosystems due to the loss of bats bats
are also threatened in the u.s. by their
attraction to wind farms again right now
batter looking a little bit of problem
they’re going to there they are very
threatened in the United States of
America alone now how can this help us
well it has been calculated that if we
were to remove bats from the equation
we’re going to have to then use
insecticides to remove all those pest
insects that feed on our agricultural
crops and for one year in the US alone
it’s estimated it’s going to cost 22
billion US dollars
if we remove bats so indeed bats then do
bring us wealth they maintain the health
of our ecosystems and also they save us
money so again that’s the first blessing
bats are important for our ecosystems
and what about the second what about
health inside every cell in your body
lies your genome your genome is made up
of your DNA your DNA codes for proteins
that enable you to function and interact
and be as you are now since the new
advancements in modern molecular
technologies it is now possible for us
to sequence our own genome in a very
rapid time and a very very reduced cost
now when we’ve been doing this we
realize that there’s variations within
our genome so I want you to look at the
person beside you let’s have a quick
look and what we need to realize is that
every 300 base pairs in your DNA you’re
a little bit
and one of the grand challenges right
now in modern molecular medicine is to
work out whether this variation makes
you more susceptible to diseases or does
this variation just make you different
again what does it mean here what does
this variation actually mean so if we
are to capitalize on all of this new
molecular data and personalized genomic
information that is coming online that
we will be able to have for the next few
years we have to be able to
differentiate between the two so how do
we do this
well I believe we just look at nature’s
experiments so through natural selection
over time mutations variations that
disrupt the function of a protein will
not be tolerated over time evolution
acts as a sieve it SIVs out the bad
variation and so therefore if you look
at the same region of a genome in many
mammals that have been evolutionary
distant from each other and are also
ecologically divergent you will be a
better understanding of what the
evolutionary prior of that site is ie if
it is important for the mammal to
function for survival it will be the
same in all of those different lineages
species taxa so therefore if we were to
do this want me to do with sequence that
region in all these different mammals
and ascertain if it’s the same or if
it’s different so if it is the same this
indicates that that site is important
for function so a disease mutation
should fall within that site so in this
case here if all the mammals that we
look have have a yellow type genome at
that site it probably suggests that
purple is bad this could be even more
powerful if you look at mammals they’re
doing things slightly differently so say
for example the region of the genome
that I was looking at was a region
that’s important for vision if we look
at that region in mammals that don’t see
so well such as bats and we find that
backs that don’t see so well have the
purple type we know that this is
probably what’s causing this disease
so in my lab we’ve been using bats to
look at two different types of diseases
of his other senses we’re looking at
blindness and why would you do this
340 million people are visually impaired
and 45 million of these are blind so
blind us is a big problem and a lot of
these blind disorders come from
inherited diseases so we want to try and
better understand which mutations in the
gene causes the disease also we look at
deafness one in every 1,000 newborn
babies are deaf and when we reach 80
over half of us will also have a hearing
problem again there’s many underlying
genetic causes for this so what we’ve
been doing in my lab is looking at these
unique sensory specialists the bats and
we have looked at genes or cause
blindness when there’s a defect in them
jeans are cause deafness when there’s a
defect in them and now we can predict
which sites are most likely to cause
disease so bats are also important for
our health to enable us better
understand how our genome functions so
this is where we are right now but what
about the future
what about longevity this is where we’re
going to go and as I said before I
really believe that the secret of
everlasting youth lies within the bat
genome so why should we be interested in
aging at all but really this is the
picture drawn from the 1500s of the
Fountain of Youth
aging is considered one of the most
familiar yet the least well understood
aspects of all of biology and really
since the dawn of civilization mankind
has sought to avoid it but we are going
to have to understand it a bit better in
Europe alone by 2050 there’s going to be
a 70% increase of individuals over 65
and 170 percent increase in individuals
over 80 as we age we deteriorate and
this deterioration causes problems for
the society so we have to address it so
how could the secret of everlasting
youth actually lie within the bat genome
does anybody
hazard a gasps over how long this bat
could live for who put up your hands who
says two years nobody won
how about ten years some how about 30
how about 40 okay it’s a whole varied
response this bat is my Otis Bronte I
it’s the longest living bat it lives for
up to 42 years and this bat still alive
in the wild today but what would be so
amazing about this well typically in
mammals there is a relationship between
body size metabolic rate and how long
you can live for and you can predict how
long a mammal can live for given its
body size so typically small mammals
live fast die young think of a maze but
bats are very different as you can see
here on this graph in blue these are all
other mammals but bats can live up to
nine times longer than expected despite
having a really really high metabolic
rate and the question is how can they do
that
there are 19 species of mammal that live
longer than expected given their body
size than man and 18 of those are bats
so therefore they must have something
within their DNA that Able’s them deal
with the metabolic stresses particularly
of flight
they expand 3 times more energy the
mammal of the same size but don’t seem
to suffer the consequences or the
effects so right now in my lab we’re
combining state-of-the-art back field
biology go ahead and catching the
long-lived bats with the most up-to-date
modern molecular technology to
understand better what it is that they
do to stop aging as we do and hopefully
in the next five years I’ll be giving
you a TED talk on that aging is a big
problem for Humanity and I believe that
by studying bats we can uncover the
molecular mechanisms that enable mammals
achieve extraordinary on cavity if we
find out what they’re doing
perhaps through gene therapy we can
enable us to do the same thing
potentially this means that we could
halt aging or maybe even reverse it
and just imagine what that would be like
so really I don’t think we should be
thinking them it’s flying demons of the
night but more as our superheroes and
the reality that bats can bring us so
much benefits if we just look in the
right place they’re good for our
ecosystem they allow us understand how
our genome functions and they
potentially hold the secret to
everlasting youth so tonight when you
walk out of here and you look up in the
night skies and you see this beautiful
flying mammal I want you to smile thank
you