Ming Gao – A Celebration of Faculty Research ~IUN~


Hello. So, I would like to introduce to you this special cells
in our body called a germ cells and tell you why sex reproduction relies on them
and how do we make them. Well for our species to continue we need sex and for
us to perform sex females and males need to produce sex cells. That is obviously eggs from the female sperm from the male, but how does our
body produce those cells? Well to look at that question let’s take a step back and
take a look at how we grew up in the first place. We all start here. This is
our birth date 0 on the top. The union of an egg and the sperm form a 1 cell
fertilized egg. That one cell divide and grow to a early embryo which is like a
little ball of thousands of cells. From there, cells begin to differentiate. Some
cells becomes our body parts, head, arms, legs. A special group of cells, they
become germ cells in our body and those germ cells exist in our body and as we
become sexually mature germ cells are the only cells in our body that can
produce sex cells. So the germ cells are the cells in our body that carry on the
responsibility and enable us to repeat the cycle of life, but one important
question remained that is from the ball to the early fetus
how do we decide which cells become other parts of our body and how do we
determine which cells are destined to become the germ cells? To study that
question, we use the model organism called Joseph Allah, the fruit flies, the
little tiny guys you find in your garbage can if you forget to clean your
garbage, these guys surprisingly, fruit flies are 78% genetically similar to us
and the many biological processes like sexual reproduction works the same way
as humans. So let’s look at how flies determine their germ cells. This is how
flies do it. A female fly lay an egg and in the same time she would put a special
liquidy material called a germ plasm in the rear end of the egg and as the egg
developed to a ball of thousands of cells most of the cells in the front end
will become other body parts and only those cells in the rear,
they contain germ plasm in them and they are destined to become germ cells and
carry on the responsibility of producing the next generation. So we wonder what is
in that germ plasm and what makes it so powerful that it can determine a cell’s
fate to be germ cells? People looked at fly’s egg and germ cell under microscope
at 200 time magnification to see what it looks like and then under 1000 time
magnification at even 50,000 time magnification under electron microscope
and those germ plasm appear as tiny little granular particles and further
analysis revealed that these particles are aggregates of two types of molecules. Proteins and RNAs. RNAs are just small genetic messages. Well what they’re
called are not important. What’s important is what these molecules can do. What they can do is they can program an early stage embryo cell and tell them to
become germ cells by turning on the germ cell formation genes in them. So this
is how flies do it. A female fly lay an egg and she put those germ plasm
molecules in the cells in the rear and these molecules turn on the germ cell
formation Gene’s only in those cells and program them to become germ cells, while
other cells they don’t contain the germ plasm so they become the normal body
parts. It turns out not just flies does that happen in humans too, yes, but not
only humans. From simple animals like earthworms, flies, frogs, to more complex
mammals like Mouse and humans, we all contain these molecules and we all use
them to determine the formation of germ cells. So these molecules are cross the
field of evolution it’s a very conserved mechanism for germ cell formation
and for animal reproduction in my lab at IUN we further pursue the questions of
what exactly in that germ plasm molecules? What exactly are those
molecules? What are those RNAs proteins? How do they work together? How do they
interact in a cell for the cell to output the correct program? So the cell
turn on the right gene and then turn off the wrong ones to become the germ cells
so we can continue to exist. People also surprisingly found that these germ
plasm molecules are present in other type of stem cells and even in cancer
cells. If we understand how germ plasm works, can we even apply the knowledge to
understand how cancer cells form? How other stem cells
form and potentially use our knowledge to cure cure cancer and genetically
engineer stem cells to cure human disorders like germs are related
infertility? That’s all the, well not all, but some of the outstanding
questions I’m pursuing. So for you to take home,
sex reproduction relies on germ cells. Thank you. [Applause]

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