Category Archives: Evoluton

Why don’t you love what I love?

This is first of multiple blog posts I hope to do regarding the discussions at Science Online 13. There are more detailed methods I want to get into but I am using this as a primer for the discussion.

A lot of the sessions at Science Online revolved around the theme of how to communicate science effectively, when to use personal narrative, how to get citizens involved in science and how to get people passionate about science like you are passionate about science.  I was interested in all of these because I am a high school science teacher and making difficult scientific concepts understandable is my job.

As I listened to the scientists talk at the various sessions I learned quite a bit about the struggles they were going through. First I want to say, I hear you. There is nothing worse than having to listen to something you love so much get diluted and simplified. It is probably like a five star chef having his meal reduced to a bland entree where all the subtle flavors and ingredients are removed. But sometimes we need to realize the people we are talking to, the people who are eating that meal, have not acquired the taste for it and want the meal they enjoy as opposed to the meal they need to learn to enjoy.

At one point I was doing research on Komodo dragon behavior at the National Zoo.  I loved speaking in the complex jargon of reptile behavior  because I was speaking with others that understood it and we could better convey our thoughts. This is a necessity in scientist to scientist communication, nothing can be left open for interpretation. However when my mom asked me about the research and what I was doing I had to radically change the style and tone to effectively communicate with her.  This is a phenomenon called “code switching” and it is most prevalent in interracial or intercultural communication. It is now something scientists need to learn to do.

None of my friends are really that into reptiles, and none of them really care about how many tongue flicks or claw rakes we recorded that day. Believe me, I wanted them to, I desperately wanted them to ask me and genuinely care about my answer. I mean this was a study to see if Komodo dragons exhibited play behavior, something that is on the more interesting spectrum of the reptile research scale.   I experienced this daily while conducting the study with two other scientists at the National Zoo.

There is an unexplainable phenomenon in the zoo world, people will pass by an exhibit with an incredibly unique animal in it with barely a glance, but put a human in there, even with just a squeegee cleaning glass and the next thing you know there is a crowd watching intently to see what the human will do next.  Now imagine this, in front of the dragon cage at the reptile house at the National Zoo you have two scientists in chairs roped off so people can’t get too close, then a third is in the cage interacting with a dragon. This is the five alarm fire of the zoo world. People desperately trying to see what is going on, literally rubbernecking a scientific experiment.  Invariably someone would always ask, “So what are you guys doing?” and I would go into the detailed explanation of the experiment , because they were there and they asked and I presumed they really wanted to know. Plus I loved Komodo dragons and wanted everyone to love them like I did.  It was here I discovered the different degrees of  “wanting to know”.  But I found that the majority of the time I was diluting this impressive animal to an understandable set of basic behaviors because the complexity was lost on the general public and they didn’t care about the specific jargon I was using, they wanted the simple grilled cheese version of the answer, not the five course meal with various sauces and reductions.

Believe me, this sucks. I often couldn’t figure out why everyone didn’t love Komodo dragons as much as I loved them. But 11 years ago I made a conscious decision to change that. I left research to become a high school science teacher because for me it was about getting the awareness out to young people and to champion for an underappreciated group of animals.

So after a decade in a classroom and many, many, many mistakes I feel I have found a decent balance as a science communicator.  I admit I have an unfair advantage, I have real time metrics in front of me on a daily basis. I get to utilize various forms of explanations and see how they are received by my audience. I get to see what works and what doesn’t and then refine them two or three more times that day until I have them perfected.  Not only that but my audience often replies back with brutal and blunt honesty, high school students will let you know if you are coming across in a condescending manner. A lot of people, and myself included , are unaware that their methods of explanation often have a condescending tone to them. It is not purposeful, but sometimes unavoidable when the person is in the position of explainer. It takes a while to pick up on your own cues and attempt to avoid them.

If you really wanted to get offended, try discussing something you passionately love and put a lot of work into what you think is a great lesson only to be met with yawns, blank stares, glances at the clock, and snoring. It takes a lot of strength to not take it personal, even when it is.

I also get quantitative and qualitative data in the form of papers, tests, quizzes, labs, etc. that tell me just how effective I was at communicating the subject matter. I can look through years of teaching and find my weak subject areas and focus on improving them.

So where does this all fit? Well the one thing a teacher has to know before they begin a lesson is “what is my end goal? What do I want to achieve with my communication? Do I want to explain? Do I want to educate? Do I want to inform? Do I want to infect? Do I want to extrapolate?” All these come with much different methods of communicating.

In science education I can’t avoid the jargon, but I need to know when to drop it into play. If I throw complex words right out from the get go and say “memorize the words” then I lost them, but if I come up with a great analogy or metaphor that the students can relate to and then slide the word in there I have them hooked. I need to sell them on cell division before I introduce mitosis. I need to make them feel like they were asking me if there was a specific word for what I was describing instead of telling them the word and describing what it means.

A subtle trick I use to hook my students is to discuss the material a few different ways and on one of the attempts pretend I am searching for the right word and let them fill in the blank for me.  This makes them feel like they are contributing to the explanation process and lets me know they are getting it. I know this is not helpful in science writing, but it is helpful when discussing science with non science people.

My end goal with my students is to get them interested in science.  At this point as juniors in high school it is not important to me that they understand every detail of biology, but that they have an interest in understanding it. Because if they have an interest, they will be open to learning the more complex material that will help them better understand what they are interested in.  I have seen this with freshman students taking conceptual physics that are literally begging their teacher to learn trigonometry so they can better understand this cool stuff they are witnessing. Yes, begging to learn trigonometry. Why? Because they were hooked by the simple grilled cheese sandwich and wanted to see if they could make it tastier not realizing they were developing a complex meal.

This is why the first thing I do in Chemistry is drop a gummy bear into molten potassium chlorate. Hook the students with a dazzling example and make them want to learn more.

I truly believe that the role of the scientist is changing. With the advent of blogging, twitter, and social media scientists are becoming accessible to the general public, and we want to be accessible because we love our science and want people to love it as much as we do.  But we need to realize if they did love it as much as us we would be talking to a fellow scientist, not a layperson.

This is why I felt the need to go up to Carl Zimmer at the conference and thank him. Often times when I couldn’t figure out how to effectively do my job, he would do it for me. I have never seen a group of inner city high school science students stay so focused on the life cycle of a blood fluke than when he was talking about them on RadioLab.  Whether the information was 100% correct was irrelevant because it led to a discussion that  led to questions, that led to researching, that led to understanding. Now they know more about parasites than most people. If I said to them “We are gong to learn about the following parasites…..” and went on to explain each one I would have lost them. But using Carl and Radiolab I had them asking to learn more. And this,  this is what science communication is all about. Generating enough interest to lead to understanding.


Filed under education, Evoluton

Thank You Charles….

Regardless of your beliefs and whether you choose to accept evolution or not, Charles Darwin is a man who deserves your respect.  Most people know who he is and that he published The Origin of Species, but very few know the pain, anguish, and suffering that went into publicly releasing this information 153 years ago today.

In 2009 Aqila wanted to go to England to see Blur play a concert in Hyde Park.  I was in, under one condition, we take a day for me to go Darwin’s home in Kent and pay homage to a man who suffered so I could understand.

Darwin was a well to do Brit with an aristocratic status who bounced around careers never content on where he landed.  Because Captain Fitzroy wanted someone of his social standing on board the HMS Beagle he allowed Darwin to come along the voyage of the Beagle as a naturalist while he spent 5 years mapping coastlines. Darwin was a young 22 when he left on the HMS Beagle and spent the next 5 years collecting specimens from all over the world while suffering from seasickness the entire time.

He returned from this historic voyage at the age of 27…..he did not publish his theory until 23 years later.  He spent  less time alive before boarding the Beagle than he did working on his theory for publication.  But it wasn’t lack of evidence that prevented him from publication, it was fear of retribution.  It would be social suicide for someone of his class to go against God, in fact when he confided in friends about his theory it was done in hushed meetings in backrooms or the privacy of his home for fear of being overheard.

As he worked on his theory and the evidence began to fall into place he grew increasingly worried about the implications of his work.  He knew he was sitting on the answer to the question of all questions, but was the world ready for it? He wrestled with this for over a decade, the majority of the time being spent at Downe House in Kent where he was surrounded by the English countryside with plenty of space for experiments in the natural world and his hobby of pigeon breeding and horticulture.  It is this place, Downe House, that is the true birthplace of the theory of evolution. The real cornerstone of this being the sand path that looped the grounds.

Darwin would do five loops on the sand path a day to exercise both his body and mind.  At this point he was suffering both physically and mentally from the stress of work.  He would often get so upset he couldn’t eat and would vomit.  He found the calm of walking the path allowed his body to let his brain work on the details of his theory.

In 1844 he outlined an essay explaining his theory which he then called Descent With Modification and even went so far as to leave a letter to his wife Emma saying to publish the essay if he should die unexpectedly.  This is a 14 years before The Origin of Species was published……14 years.  He knew this was his life’s work, he knew this was what he would be remembered for, he knew the importance of this information…..but even so, he would not publish it.  So he spent the years publishing different essays and monographs on everything from geology to barnacles, all the while keeping the single most important scientific discovery in human history to himself and a few close friends.

Imagine you stumbled upon the answer to how the Universe began but couldn’t tell anyone.

One of the turning points in Darwin’s decision to finally publish was the death of his daughter Annie in 1851.  It crushed him and he blamed himself because he married his first cousin and believed his children suffered from the closeness in relation. He had trouble accepting a God that could be so cruel…he even vocalized this when describing parasitic wasps. An insect that paralyzes insects and lays their eggs in them to provide live food when they hatch.

He continued to suffer and was told by doctors that if he did not stop working so hard he would die from the stress…..but Darwin didn’t stop. He dealt with the physical pain, no doubt well accustomed to physical discomfort while working from five years of seasickness on the Beagle. So he walked his path five loops a day and he wrote.  In 1856 confidant and close friend Charles Lyell told him to put these works together in one book called Natural Selection.  Through the year of 1857 he organized his book and then in June of 1858 he received an essay to read from a young English scientist working in Malaysia who through his observations had developed the exact same theory as Darwin himself years earlier.

Darwin was crushed.  Decades of work only to get beaten to the punch at the last minute.  Because of his own fear and insecurity he would be forever lost in the annals of history and all the pain in suffering would be for naught.

Wallace was not looking for publication but Darwin offered to publish both their essays together.  Was it cowardly of Darwin to wait until someone else could be a target for the backlash? Maybe, but courage isn’t doing something without fear, courage is doing something in the presence of fear.  A fear so great it was physically destroying him.

In June of 1859 they presented the information to the Linneaen Society, strangely the presentation raised very little response.  During this time Darwin’s health declined drastically and he struggled to finish The Origin of Species.  His friends encouraged him to keep working and finish it for publication.

So he he walked…five loops on the sand path.

On November 24, 1859 all 1200 published copies of The Origin of Species sold out.

Then came the storm. Richard Owen, the head of the British Museum of Natural History and well respected scientist of the time attacked Darwin and his theory in public forum.  Darwin’s nightmare began to unfold as he was bullied publicly by both Owen and his following as well as local newspapers, even going so far as to portray a drawing of Darwin as part monkey part man.

But Darwin was no longer alone.  With all the cards on the table other scientists began to support him, most notably is one of my favorite characters in science, Thomas Huxley, nicknamed “Darwin’s Bulldog”.  He had the tenacity and confidence to attack Owen’s establishment head on in public.  Most notably in the Oxford debate on evolution in 1860, which Darwin did not attend.  Samuel Wilberforce spearheaded the religious side of the debate and it was here that Huxley solidified his role as Darwin’s defender.

The topic of descending from apes was being scoffed at by the religious side, how ridiculous a person who have to be to believe this.  It is believed that the culmination of this debate came when Wilberforce, believing he could shake Huxley said “..whether it was through his grandfather or his grandmother that he claimed his descent from a monkey.”

Without missing a beat Huxley replied “I wound not be ashamed to have a monkey for my ancestor, but I am ashamed to be connected with a man who used his great gifts to obscure the truth.”

Roughly saying “You have a great gift of intelligence and you choose to use it to hide the truth”.

Whether it played out like this word for word is up for debate, but this was the gist of their back and forth.

Darwin, now removed from the front lines of debate continued to work for the next 20 years and publish more work on everything from carnivorous plants to the animal mind. He also published 6 more editions of The Origin of Species along with the historical Descent of Man in 1870.  He kept a full garden, a greenhouse full of carnivorous plants, bees, orchids…

…and he walked, five times a day on the sand path.

His health continued to decline and in 1882 surrounded by his family Darwin died of heart failure. He was slated to be buried in St Mary’s Church yard in Downe, but the head of the Royal Society William Spottiswoode petitioned for him to have a state’s funeral and laid to rest in Westminster Abby close to John Herschel and Sir Isaac Newton. An honor held only for heads of state and people of national significance.

The petition was accepted and,  Charles Darwin, a man who was convinced he would become the worlds most hated man was honored with a states funeral and was carried to his grave by close friends Thomas Huxley, Alfred Russel Wallace,  William Spottiswoode, and Joseph Hooker.

My pilgrimage to England started here, at Darwin’s resting place where I expected to find an ornate monument to Darwin, but was greeted by a modest stone that simple says ““CHARLES ROBERT DARWIN BORN 12 FEBRUARY 1809. DIED 19 APRIL 1882.” It was a fitting grave for a man who preferred to be in his study than in the spotlight.

I just sort of stood for awhile, looking for some sort of emotional response, but nothing of significance came forth.  It was just a stone, there were crowds of people, crying children, and little atmosphere for reflection.

The next day we then took a train, two buses, and walked 30 minutes down a narrow road with no sidewalks to Downe House. We took the tour of the house with a small group and I began to feel a tinge of emotion, as we toured from room to room seeing the actual spot Darwin worked I started to get a surreal feeling. The reality of where I was, the significance of this spot to me personally, began to set in.  My whole life has been guided by work that was penned in this very spot.

But it was Darwin’s path where it finally set in.  I began to walk it, I felt an initial giddiness but as I moved further from the house and other people I began to feel it. As I walked the path my mind began to wander, I thought of Darwin walking this path as I am now, I thought of natural selection, the origin of humans, and the greatness of his theory…..but then my mind wandered and the world around me slipped away….I was in CCD, in the sixth grade, a nun was scorning me for talking about evolution during class….8th grade forced to sit alone in CCD to reflect why I shouldn’t ask the nun how God created us when we evolved from primates…I saw myself stomping through ponds collecting anything living and placing them in a coffee can complete marveling at the variety of nature, not able to articulate the beautiful words of Darwin… from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved…I was entering college to pursue a career in science…I was sitting in the Smithsonian studying Komodo dragon behavior….I was teaching evolution to seniors in a class I designed as the head of science at a private school called Evolution and Comparative Anatomy….and here I am in England….my life, my whole life guided by a theory that was born right here….I became completely overwhelmed…I thought of Darwin waking this path, suffering intense physical and mental pain as he mentally penned the words of his life’s work.

I wanted so badly to tell Darwin thank you, that his work answered the question that no one could answer for me during my young life….I knew it could never be and as I kicked a stone on the path on my final lap, I remembered a snippet I read about how Darwin would put a small pile stones down and would kick them aside as he walked so he didn’t have to be bothered mentally to remember what lap he was on….. and it came full circle……there I was kicking stones on the sand path at Downe House….and for a moment….I was as close to Darwin as I could be.  I picked up the rock I kicked and held it, the only tangible connection I could have and kept it.

So as I sit here in a rocking chair in the back of the living room of my parents house during my Thanksgiving visit.  My wife and family are watching TV and occasionally asking me what I am so intensely focused on…I guess I was just trying to find a way to simply say…

….Thank you Charles, I am eternally grateful. Your suffering put mine to rest.

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Filed under Evoluton

Mothers, A Molecular Look

I was sitting down trying to figure out the best way to honor Mother’s Day with a blog post.  Sure I could show cute pictures of animals and their babies (but I have done that before), but I decided I am going to do it my way….

At this juncture in human history almost every person knows about DNA, or by its formal name Deoxyribonucleic acid.  DNA is the ingredients list for life (notice I did not say instruction manual, this is a common misconception, DNA merely lists the parts but does not explain how to put them together).  We all know the story, half of your DNA comes from your father and half of your DNA comes from your mother and a brand new never before seen human arises from this six foot long molecule.

Some of you may be sophisticated enough to know that the DNA molecule is shaped in the form of a double helix.  If you can’t visualise that, here is an image of DNA….
It is a little cartoony for my taste but you will see why I chose that specific one in a moment.  So if you laid this double helix out flat it would look like a ladder.  The rungs of the ladder are base pairs and they join in the middle  of the rung through a hydrogen bond.  There are four base pairs in DNA, four, for every living organism in the world there are only four different base pairs, Adenine, Thymine, Guanine and Cytosine, that means that whether you are a bacteria or a human your parts list is all written in the same language.   As you read this the DNA in your body is dividing and replicating over and over again hundreds of millions a time per day.  Every single one of your somatic cells (every cell but sperm and egg cells) has a strand of DNA residing in it.  So why not the sperm and egg cell? The sperm and egg cannot have a complete set of DNA because if they did when they met they would have twice the amount they need to produce an offspring. So our bodies half the DNA in our reproductive cells in a process called meiosis so that when the sperm meets the egg they will form one new whole DNA strand…..aka you.  This is important because this what gives sexually reproductive organisms so much variety, the constant recombination of DNA.

So there it is, your father gives half and your mother gives half.

Well not quite.

So lets jump back a minute, every eukaryotic cell, basically every organism besides bacteria, has a double helix shaped DNA molecule. So what does Bacteria have? Circular DNA.  It is simple, easy to replicate, and limited in what it can do, but as you can tell bacteria are doing just fine.  Bacteria do not recombine DNA, they simply continually make new copies of themselves, changes occur due to copying mistakes in the DNA.

Here is the look of an average bacterial DNA.

For our purposes the words are not important, what is important is the shape, circular.  So that is one of the major differences between us (humans) and bacteria, the shape of our DNA.  However like I said earlier, both bacteria and human DNA are written in the same language, but again, not important for where I am going with this……which leads us to the last piece of the puzzle that this blog has become…..lets talk about mitochondria.

For those who do not know, mitochondria is a tiny organelle (this means a structure inside of a cell, like organs in your body) in our cells that produces a material called ATP. Why is it important? Because ATP is literally the reason you can move, breath, pump blood, fight disease etc.  ATP is the battery of the cellular world.  It fuels every cell in your body.   Here is a little look at this wonderful little organelle.

Now this is where things get really interesting.  In mitochondria there is something strange, hiding in this structure is DNA.  It is unusual enough to find DNA inside an organelle, but it gets even stranger.  Don’t forget all human DNA is in the shape of a double helix. Well the mitochondrial DNA (mtDNA) is not in the shape of a double helix.  Surprisingly enough the shape of your mitochondrial DNA is in fact, circular!  Why is it circular you ask? Great question.  Let me show you a picture of mitochondrial DNA. 

Does it look familiar? It should because as you can probably put two and two together it has the exact same shape as bacterial DNA, one of earth’s oldest living organisms.   This is also why mitochondrial DNA is shaped differently than nucleic or regular DNA.  The origins of mtDNA stem directly from bacteria DNA.  Mitochondria were at one point their own cell before being modified.  In fact there are similar genes between the two.  Without getting into too much detail there are certain cellular processes, for instance ATP production and electron transport that are the same in every organism, so it makes sense that the gene to do this will be the same for every organism. For our purposes this is true.  The genes on human mitochondrial DNA are very ancient and linked to electron transport chains and protein synthesis.  Interestingly enough mitochondria does not recombine with your normal DNA.  It does the same thing as bacteria DNA, makes copies of itself.

So we know how circular DNA got into mitochondria, but how did the mitochondria get into us? The short of it? Way back in the day eukaryotes being so much bigger than bacteria could easily ingest them into their cell and essentially trap them there.  The mitochondria being such a wonderful producer of energy developed a synthesis with the larger cell.  Now our cells have little mitochondria in them.  Which as you now know, we desperately need to survive. So here we see evolution in action.   But I know what you are thinking “thanks for the science lesson but what does this have to do with Mother’s Day?”

Great question.

So now that you know about the mitochondria in your body and it’s circular DNA I want you to hold that thought while I explain reproduction to you. Now I know most of you might think they don’t need a lesson in reproduction, but I am not talking about the “Sometimes when a man and woman love each other they express that love physically…..” speech.  No, I am going to explain to you exactly how this works.

As you know you get half of your DNA from each parent, and this half is contained in either a sperm or an egg depending on the sex.  But how does this happen and why is it important?  Let’s look at males first, because as in most instances, they are just simpler.  A male produces sperm, which in essence is nothing more than a DNA transport vessel with a one time use.  So how is sperm produced? Well when the cell begins to divide it does something with the DNA, it copies it. So now the cell has two strands of DNA.  Then the cell splits into two cells with one DNA strand in each, then those two cells divide again making 4 sperm cells with four halves of DNA.  From one cell we get four sperm.  Here is a simple diagram.

Now, lets maintain a level of maturity here as I discuss the actually sperm cell.  This cell is very unique, and highly modified to do one thing. Deliver the DNA.  Much like a man, there are no frills here.  Precious cargo in a container and bare bones, stripped down vehicle built to move. The sperm cannot be weighed down with nonessential structures.  It is the cafe racer of the cell world.  What this means is that the cell does not have a long lifespan because it does not have what it needs to carry out sustainable functions.  It only has what it needs to survive for 24-48 hours.

However structurally it is pretty amazing, it truly is a feat of evolutionary engineering.  Lets take a closer look at it.  As you can see in the diagram the head is where all the importan material (DNA) is kept.  The rest of this cell is made solely for the purpose of transport.  Now let me quiz you for a second.  Having just learned about mitochondria and how they produce ATP, why do you think we find a bunch of it clustered in the mid-piece?Hopefully you thought “Well mitochondria produce ATP, ATP is fuel, so ATP is going to power the flagellum (tail) of the sperm so it can propel itself.”  If you said this then you are correct.  However remember the sperm is on its own with only 24-48 hours supply of materials.  After that it can no longer produce ATP and dies.  Unless it reaches the egg and the head of the sperm is absorbed into the egg leaving out the mid-piece and tail and fertilization occurs.

Which leads us to females, and just like women, nothing is simple.  But I am going to break it down for you in a way that will make it somewhat easy to understand.   To begin with we need to understand how an ovum (egg) is produced for reproduction and how exactly this relates to the female cycle. Bear with me men, I know it is awkward but that is because it is mysterious to us, and thus can be used against us by women.  So if you educate yourself on the workings of it you can actually use it to your advantage.  I can’t tell you how many times a woman has said to me “You’re a man you don’t know anything about it.” To which I reply, “Do YOU know anything about it?” Side note: women do not appreciate this.  Amazingly enough most women have no idea what is actually going on.  Sure they can tell you the basics, but not the important details that actually leads to the effects they feel.

So lets educate.

A woman is born with every single egg she will ever produce in her lifetime.  Let me say that again, at birth a female’s ovaries have in them ever single egg she will ever produce.  That means she carries them with her throughout her whole life and like most things the longer they go unused the more damaged they can become from environmental pathogens (chemicals, disease, etc.).

So seems simple enough, all the eggs are there, much simpler than men right? Wrong.  Because just like the vessel that transports these eggs a lot of preparation must occur to go out. Like the sperm the egg needs to make sure it has only half a strand of DNA so the egg in preparation to leave the ovary must undergo a change.

A normal human female goes through a 28 day cycle.  The first 7 days is dedicated to shedding the unused materials that were prepped for pregnancy, this is the time when interactions with females are best avoided, and jokes should be kept to zero.  Then on the 8th day they enter the follicular phase, this is the preparation of the uterus to receive a fertilized egg.  This takes about another six to seven days and then the female enters the ovulation phase.  This is what I want to focus on.

When the uterus is ready the female body releases FSH, which is the Follicle Stimulating Hormone.  This triggers the final preparation of the egg before being released into the fallopian tubes.    FSH is responsible for one of my favorite words in biology…..oogenesis.  That is not a misspelled word, it is pronounced oh-oh-genesis.  Oogenesis is the female equivalent to spermatogenesis.  Like you learned, from one cell in a male they can produce four sperm cells.  Not so, in a female one cell will only produce one egg cell.  However it needs to go through the division process to get the DNA molecules down to a single half strand.  The following diagram will make this a little easier.  Unlike the spermatogenesis we get one egg cell and three polar bodies, which do not contain enough materials to make a functional cell.

The one egg cell needs as much as the material as possible because it is going to be receive nothing but DNA from the sperm so it is responsible for having all the life support needed to make sure once fertilization occurs the newly formed zygote can carry out cellular division.  So all the important organelles needed to carry out cellular activity are contained within the egg cell including the ever important mitochondria.

Think about that for a minute. Now add that to what you have learned about the sperm, mitochondria, DNA, and fertilization.

Do you see where this is going? Remember my previous statement. “So there it is, your father gives half and your mother gives half…..well not quite.”

When the sperm fertilizes the egg, the only thing the egg takes in is the DNA. The rest of the materials, including the mitochondria in the mid-piece are spent and left outside. More importantly, just like bacterial DNA, mitochondrial DNA only recombines with itself……..mitochondrial DNA only recombines with itself……..mitochondrial DNA only recombines with itself….

Yes, that is exactly what I am saying. Every human being on earth is carrying with them the same little circle of DNA that came from their mother, and their mother, and their mother, and their mother, and their mother, and so one and so forth until we get back to her……Mitochondrial Eve.  The mother we can all be traced back to, she is estimated to have lived more than 200,000 years ago, and for all this time her little circle of mitochondrial DNA has been passed from mother to child over and over and over again without any influence or recombination with the DNA of the father.

One unbroken molecular chain linking us all to our mother.

As I sat trying to figure out what I could write to make my mother feel special on a day when so many other children are doing the same thing I wanted to do something that would go beyond the normal praise.  I wanted to do something to make her realize how truly important her role is as a mother.

So mom, while you are exceptional at being a mother to a rather unique son, I wanted you to realize that you have accomplished the most important task in life, something no man can ever do, you connected me to every human on earth and kept that 200,000 year-old unbroken molecular chain intact.

Thank you.


Filed under Evoluton