Its Time for Intelligent Design
[Music]
i’m an engineer
and one of the first examples of
engineering i can think of
something that happened in high school a
group of students including me
were asked to build a bridge between two
tables
using some saran wrap some newspaper and
some tape and not
a lot else we thought about it for like
five seconds
and we decided we were going to build a
bridge based on
newspaper triangles because we thought
those were very strong
and what we ended up making looked like
this as i think you can imagine
this paper bridge was not very good it
didn’t work at all
what i learned from this experience was
two things first off
making something that’s a good idea
making it robust
requires some thought secondly don’t
build bridges out of paper
it’s not the right choice and won’t work
well
fast forward to the present day i just
finished my phd at mit
in biological engineering so i don’t
build bridges
i build bacteria that work differently
and have
new functions often when i tell people
this
like my uber driver or my dentist
i get the response aren’t you playing
god
this is a really good question and i
often brush it off so
today i want to set the record straight
and i want to actually give an answer to
this question
biology is really beautiful and
wonderful and it’s inspirational
and it’s also imperfect like the paper
bridge
that i built badly in high school
biology isn’t robust
and it could be composed of better
materials
we can and we should make biology better
the first thing to know about
engineering living systems
is that it feels super different than
engineering anything else
biological engineering is like
discovering that a
super messy alien spaceship has like
crash landed on earth
and we need to go through every
component and backwards engineer it
so that we can understand like the
tiniest bit about how it works
and have some chance at managing to
change
what it does biological systems are so
foreign
so alien they work and are structured in
ways that are so completely different
than the way human engineered systems
are built
that it feels a lot like an alien
spaceship
and in fact that’s because biological
systems weren’t made by humans
organisms are absolutely the most
sophisticated machines we know of
and they came about after four billion
years
of random chance no humans
and it shows right in addition to the
beauty and wonder of biology
it’s also unfinished and imperfect
and today i want to talk about two types
of imperfection
in biological systems that are the same
as the problems with that bridge
i made in high school first biological
systems
are not always very robust and second
they could be composed of much more
suitable materials
so first i want to give you an example
of a
really really dumb mistake in the human
genome
that gives people cancer normal healthy
cells
have lots of little molecular machines
called proteins
that they use to do all the normal
things that cells need to do to be alive
there are proteins that replicate your
dna um there’s proteins in your eyes
that sense light
proteins in plants that help them absorb
sunlight
proteins they basically do all the
chemical heavy lifting
in in living systems proteins are
physically composed of a bunch of
building blocks which are called amino
acids
so to make a protein you string the
building blocks together
and that string will fold up into like
the functional version of the protein
that performs some sort of function
these molecular machines are so central
to having a happy healthy cell
that it’s super important that your body
is able to manufacture
them correctly and also pass on
instructions
for how to do that to your descendants
and
in fact your genome is composed of those
instructions each gene in your genome
encodes instructions
for how to make a protein when you go
out in the sun you get a sunburn
it will physically damage your dna
which sometimes will mess up the
instructions for how to make one of
these proteins
and and here’s where the problem comes
in one of the most
important types of proteins that
protects you from cancer are proteins
that basically do quality control
they double check to make sure the cell
is operating right
and protect you from cancer so mistakes
in the dna
for how to make those proteins those
mistakes are especially bad and
especially likely to cause you cancer so
over here on chromosome 9 of the human
genome there’s two proteins
both of them are essential quality
control proteins both of them protect
you from cancer
and there’s something like fishy about
how
their the instructions are written down
which is that the instructions are
written down like
on top of each other but offset by just
a little bit
using like physically the same piece of
dna
and that means that any mutation in that
part of chromosome 9 is super likely to
mess up
either one or both of these super
essential quality control proteins
in fact mutations in this area of
chromosome 9
cause lymphoma and carcinoma which are
both types of cancer
from an engineering perspective this is
just an infuriatingly bad mistake
just scooch one of the proteins over
like they don’t have to be encoded on
top of each other
in a genome that’s three billion bases
of dna long how can you possibly not
have space
to encode these two essential qc
proteins separately
to me this area of the human genome is
like
painfully embarrassing over billions of
years of evolution genomes will
accumulate these errors
it’s just heartbreaking because any
human engineer would catch this
no one would engineer this deliberately
it sucks because
this mistake has caused there to be a
ticking bomb
in the genome of everyone watching this
a ticking bomb that nature left us
as a present to discover and i think
this would be a note
i would thus put on the human genome
report card mostly good but also
gigantic mistakes
it’s quite a paradox there’s so much
beauty and
so many fantastically elegant solutions
that
nature has presented us but they come
alongside huge mistakes
things nature didn’t get around to
fixing and i think we
tend to hesitate to criticize biology
because of its beauty on the whole that
does us all a disservice
because we let our awe
of living systems prevent us from
recognizing that there are
fixable problems that we could improve
upon
and i think when people think about
human genome editing
they get really carried away in
contemplating the morality
of like parents editing their children
to be tall and blonde and good at
basketball
and that’s not what’s going to happen
human genome editing is going to be used
to correct
egregious issues with the human genome
that arose because
our genome is the result of 4 billion
years of random chance
in the history of the universe no one
has ever sat down
and been like how should this work what
would work well
let’s engineer this in a way that makes
sense and is a good idea
no one has ever done that and that’s the
person i want to be
i want to be the person who engineers
nice clean robust genomes and i want to
do it with some rigor
and really careful thought i want to add
some
intelligent design if you will into how
living organisms are built
so in fact during my phd i worked on
making biological systems better
i wanted to make a systematic change
that would allow biology to be more
extensible
one of the big limitations of biology
are the basic building blocks themselves
so there are only 20 different types of
amino acids and when you look at the
amino acids
chemically speaking they’re actually
kind of boring
like one very easy way to see this is to
look at them on a periodic table
out of all this good stuff only five
chemical elements
appear in proteins this would be like
if the alien biology spaceship landed on
earth and we find that it’s entirely
made out of
paper it’s perhaps amazing and
inspirational that they managed to get
so far
light years with so little but at the
same time like
maybe we could get some heavy metals up
here because they’re like good for
things
so in grad school i worked on genetic
code expansion
which is where we’re trying to expand
biology to include
more interesting building blocks that
have new properties i
told you before that genes write down
instructions for how to create proteins
and the way these instructions are
written is actually very simple
the gene is just composed of a list of
three-letter names or codons
for each amino acid in the order that
they should be added to the string which
will fold up into your protein
what i worked on during my phd is
creating bacteria that have
both a very simple and also like very
fundamental change
they use longer names to refer to
building blocks
so they use four base codons rather than
three base codons
longer names means more possible names
and thus more possible amino acids and
that would be amazing
do you want to make proteins that break
down plastic bottles
use new amino acids proteins that are
next generation versions
of therapeutics like insulin or
interferon
those can be improved again with new
amino acids
if you want to make new types of cancer
therapeutics
that aren’t possible today you have to
use new amino acids
expanding biology to be more chemically
sophisticated
this is the future and so to answer the
question i posed at the beginning
aren’t you playing god the answer is yes
we’ve been gifted with an amazing
starting point a natural world
that’s full of plants and animals and
people and now we can take it from here
we can take these systems and smooth out
the sharp edges
that nature didn’t get around to fixing
and we can make our own genome more
robust
in order to prevent cancer we can expand
the fundamental chemical basis of life
so that we can use biology to build
better stuff we can
and we should finally intelligently
design
life