Mutation in Field Mice:
Once apon a time there was a mouse named Ralphred, Ralph for short. All the other
mice noticed that there was something different about Ralph. Ralph could digest
anything! Ralph was often seen polishing off a dead branch for dinner. All the other
mice were very worried about Ralph so they decided to take him to a wise old
mouse named Freida. Freida lived up high on a hill so the mice trekked up there
with Ralph to see what she would say about this curious condition. On the way there
Ralph literally ate his hat.
Hmmm… Freida said while peering at Ralph through her horn-rimmed glasses. I
have never seen anything of the like in all of my 40 months of living. I do have some
learning though and I would say that this phenomenon must have been produced by a
mutation. Do you have any children Ralph? In fact, Ralph had two children and both
of them could eat anything, just like him.
Yes, I have two children, Ralph answered. One boy and one girl mouselet, they both
can eat anything, just like me. Freida shifted in her seat.
Well, she started. For this mutation to be passed on to you and your children it must
have occurred in one of your parent’s reproductive organs. I think this mutation is
going to positively effect our species. Make many more children Ralph; this mutation
will be very useful in the winter months.
Ralph came home and told his wife what had happened. I will have to go away for a
little because I want to know more about this mutation from Wise Old Badger. Freida
told me that he would know more. I will be back soon.
Ralph made his way to Wise Old Badger. It took him many days of hard travel and he
even had a scare when an owl swooped very close. Finally he reached Wise Old
Badger’s tree stump.
This is a curious condition and I can explain more about it. This mutation probably
occurred during the transfer of information from the DNA to the ribosomes. Something
must not have been copied right so it created an entirely new protein! This protein
happened to be an enzyme and this new enzyme can break down something that seems
to be in many things that we (meaning most animals, but obviously not you) cannot
seem to digest. I am not sure what this substance is but time will tell if we have figured
it out or not. This is a very good mutation that should stay in your gene pool. This
protein turns cellulose into glucose, which can then be made into ATPs, which give us
the energy we need to live. Your offspring will have a much higher chance of living.
Congratulations! You are a very lucky father.
Thank you! Ralph exclaimed, shaking badger’s paw.
Be very careful on your return trip! Badger warned.
I will. Ralph replied seriously.
~30 years later~
Shanti was swinging on the swings and looking thoughtful. Remember granduncle
Ralph?
Snowball chimed in with: of course! He’s like everyone in this town’s uncle or
grandpapa or something! He followed this little speech with a tumble, head over
heels down the hill. For which the white mouselet had gotten his name.
Yeah, well I’m named after him! Ralph XXI boasted, sitting on the grass and chewing
on a stick.
Tess had to get her say in: Because of his mutation we are thriving, even in the cold
winters when there’s not much food for energy available. She flopped down on the
grass.
Moonbeam added thoughtfully from her spot of sun a short distance away from the
group: We are doing so much better than the shrews. Our town has grown huge!
Chocolate gloated: Yeah, theirs is barely a few huts. She was swinging higher and
higher.
From up in a tree Lemondrop cheered: and it’s all due to Great Uncle Ralph!
Snowflake had been listening in on their conversation. Want to know why? The
white mouse asked. Come inside and I’ll explain it to you. And
Snowflake was almost 4 months old and she had already been to a special school in
a different village where they taught her new and higher knowledge.
Snowflake made her way over to the chalkboard which had a few nibbles and a bite
taken out of it (we can only guess who made that). This is what she drew on the
board:
This is the basic shape of starch. We all have an enzyme (which as you know is a type
of protein) that is meant to break down starch. The enzyme must fit in perfectly to be
able to break apart the starch.
I don’t understand! Snowball characteristically whined, he was the youngest of the
group.
Shhhh! Called Tess, this is interesting!
I guess this is a little beyond you guys, Snowflake admitted. Well, the long and short of
it is that the starch gets broken down into glucose. Once it is glucose it goes through
the 3 steps of cellular respiration to become a molecule called ATP, which is energy
that your body can use. She glanced at Tess, anyone who wants to know more can talk
to me after class.
Snowball let out a discontented squeak and began knowing on his desk.
Snowball! Snowflake rarely shouted but when she did the recipient, more often than
not was Snowball. Please stop knowing on your desk. Snowflake implored. Snowball
stopped but didn’t look very happy about it.
Now, what you need to know is that your mutation has created a new enzyme. This
enzyme can break down cellulose. This is very important because cellulose is what cell
walls are made up of. The thing about cell walls is that they are found almost
exclusively in plants, fungi and some other cellular beings that we don’t eat. Cellulose is
a very starchy substance that before now we couldn’t break down and turn into ATPs.
It would just cycle through our body and end up in our poop.
Eww! Chocolate muttered under her breath.
Tess raised a paw. Snowflake nodded at her. Well, I was wondering how Ralph got
this mutation in the first place, I mean why wasn’t it around before him?? It sounds like
a good idea to me!
Well, Ralph must have gotten it from one of his parents. I don’t know exactly what
happened but somehow there was a mutation in the sexual organs of one of the
parents. This cell was then selected to go through Meiosis, which is a special process in
which one cell splits goes through a complicated process in which it splits twice and
ends up as four cells that each have half the DNA (or information) of the original cell.
Ralph must have gotten one of the four that had the miscopied or mutated information
on it. This cell then met with the cell from the other parent and information was
shared and added back up to become a single cell that divided its self many times to
become Ralph.
By that point everyone except Tess and Moondust, who was staring out the window
but still listening, had fallen asleep.
Because this trait was passed onto most of Ralph’s children, and because it’s still alive
and well in our population it must have been a dominant trait.
Tess raised her paw again. Since everyone else is asleep can I ask about the cellular
respiration now?
Yes, well I guess you can. Cellular respiration has three parts to it, glycolysis, which
produces 2 ATP molecules, the Krebs cycle, which also churns out only two molecules of
ATP and the Electron Transport chain which spits out 32 ATP molecules.
Why bother with the first two if they don’t make many ATPs? Tess’ eyes were shining
in anticipation.
Well, glycolysis breaks down the glucose so that the Krebs cycle can use it and then the
Krebs cycle creates high energy electrons which the electron transport chain then
milks to make their 32 ATPs.
So, it’s all like teamwork, right? Moonbeam piped up from her corner.
Very good, Moonbeam. It is all about teamwork.