Genetic Bottleneck…one simple theory

Mary Connealy Header

You’re reading about a cowboy. . .which leads you to Wyoming. . .which leads you to a house made purely of fossils. . .which leads you to animal

extinction. . .which led me to something called a genetic bottleneck.


I’d never heard of such a thing.

Here’s the definition of a genetic bottleneck. (It has NOTHING to do with cowboys) A genetic bottleneck is a significant reduction in the size of a population that causes the extinction of many genetic lineages within that population, thus decreasing genetic diversity.

Now what tickled in the back of my brain was endangered species. If there are very, very few of the animals left they tend to all be related. You start running into trouble like you would if a. . .oh. . .a male dog had puppies with one of it’s own daughters. There are tendencies for birth defects, the same reason cousins are forbidden to marry.

So, though I wasn’t familiar with the term, as I read I realized I was familiar with the concept.

Did you know there is a genetic bottleneck for people? Huh? Huh?

Humans have remarkably little genetic diversity, especially in comparison to our closest living relative, the chimpanzee. I read that online. I’d never heard that humans were more or less genetically diverse than other creatures. What does that even mean?

neanderthal manThe genetic bottle neck brings me to creatures like Neanderthal Man, troglodytes, to use a more generic–and no doubt incorrect–term. Cave men.

All of the ‘human-like’ cave men come BEFORE a genetic bottle neck in human history.


Here’s one of the more popular theories about why there aren’t human-like creatures on the earth besides humans. The Toba supereruption occurred between 69,000 and 77,000 years ago in Indonesia, and it is recognized as one of Earth’s largest known eruptions. The related catastrophe theory holds that this supervolcanic event plunged the planet into a volcanic winter, which resulted in the world’s human population being reduced to as few as 1,000 breeding pairs. This created a bottleneck in human evolution.

Okay, now think about it. This is SIXTY-NINE THOUSAND YEARS AGO.volcano

We read all the time about earth history being millions and millions of years old. And yet here they’re saying that about. . .oh. . .70,000 years ago, a drop in the bucket of earth’s history, there might have been as few as 1000 ‘breeding pairs’ (let’s go ahead and humanize this and call them PEOPLE. . .MARRIED PEOPLE) on the planet.

Another place used FIFTY THOUSAND years ago. Another said Neaderthal Man vanished THIRTY THOUSAND years ago.

Okay, now we’re getting down to a very imaginable number because honestly it’s impossible to think of one million and not just be overwhelmed by it.

So, I’ve just got a question.

If the ‘genetic bottleneck’ proves that whatever men survived grew into the current population of the earth. And they’re theorizing a catastrophe of some sort, the Toba supereruption being one possibility. . .I’d like to submit my own theory of why, suddenly as recently as 30,000 years ago human life on earth became SMALL and very genetically similar–sort of like FAMILY. Now I’m no scientist. Not a paleontologist or biologist, but I am a THINKER.

How about (brace yourself) ………..CREATION!


How about if that was the point in the creation of the earth when God made man.

Or (brace yourself again) how about  a Great Flood. Noah and his family. . .now there’s a genetic bottleneck for you.


I’m just saying–all these scientific theories–well, I get it. I get that they’re trying to explain earth history without including miraculous intervention by God. That’s their job. “If God didn’t do it, then how did it happen? Maybe this, what if that…?”

But just once in a while, like when I’m looking at muddy water, I wonder–How long would I need to stare before LIFE would come crawling out. And if it did, how long would I have to stare at a one-celled mud slug before it evolved into a kangaroo and a Swedish Ivy plant?

Think about the land around you, the spectacular spring blooms and the magnificent trees and the Grand Canyon and the sweeping plains of Nebraska and Kansas and buffalo and mountain lions and alligators and carrots and watermelons and bumblebees and cockroaches, ask yourself, if this all did come from some one celled critter crawling out of a prehistoric mud hole, then isn’t that a BIGGER miracle than God just saying, “Let there be light!”

Wildflower BrideAnd I’d also like ONE example from anyone of one living creature that, in recorded history, has evolved. Seriously, I mean I know these things take a long time but c’mon, one thing. One time a chicken laid an egg and a baby was born that could…breathe under water. I can think of some animals that have adapted… adapting is very different from evolving. Where a black and white moth changed to more black than white when London became sooty. But there’s no genetic difference there. 

Either way, out of supposedly millions of years of earth history, i think we can make three statements.

1) Humans only appear in their current form a few thousand years ago.

2) Nothing has evolved since we’ve started paying attention–an no, going extinct doesn’t count.

3) The world around us is a miracle.

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Author of Romantic Comedy...with Cowboys including the bestselling Kincaid Brides Series

36 thoughts on “Genetic Bottleneck…one simple theory”

  1. You are so right, Mary! Thank you for the post and the reminder that life is a miracle from the Lord.

  2. I’m with you, Mary. It takes much more faith to believe that chance made everything happen in such a perfect way than to believe a Creator spoke it into being with divine purpose and a pre-conceived plan.

    I once heard a preacher say that if you were to stumble upon a watch, never having seen one before, and you noticed all the intricate mechanics of the gears and springs and case working together in harmony – your natural inclination would be to look for the watch maker, not to assume all those pieces had somehow fallen together by chance.

    I have a great respect for scientists and those who thirst to explain the unexplainable, but sometimes the simplest answer is indeed the correct one.

  3. Good morning ladies. Hectic morning and I’m just now checking it.

    I’m writing a book right now where they find fish fossils in the high up Rocky Mountains. You’ve probably all heard that.

    It’s true.

    They say those mountains were once under water. So why not Noah? Huh? 😀
    I’m having a lot of fun with my hero and heroine bickering over that…and a few other things…while they occasionally end up kissing.


  4. Very thought-provoking post, Mary. I do agree, that it takes much more imagination to believe in evolution. It just doesn’t make any sense. What would cause a gopher to change into a bird and fly out of his dark hole? Maybe the early creatures were all shapeshifters. 😀

    I prefer to believe God said “Viola!” and the world came to be.

    This genetic stuff got me thinking. My grandmother had ten kids, over half of them boys. None of the males had a son, so that line of the Robinsons died out when my dad died. We’re looking at the same thing happening to my husband’s side of the family, unless one of our sons has a son–and three of the four aren’t married yet. Something to think about.

  5. You know, Vickie, this is weird (maybe we’re related way back) My grandfather was from a family of nine. Four or five of them boys. Of them all, only my grandfather had a son. One male descendent to carry on the name. (not a RARE name so it hardly matters)
    My dad had eight kids, and there are many, many grandchildren but of my three brothers one had two sons and TADA one had five sons. So he’s ‘saving’ the name.
    Good boy. And his wife is a really good sport about it all. 🙂

  6. I get that they sort of change slowly over time.
    I mean look at hybrid flowers, the roses change color and get bigger and smaller.
    All sizes and shapes of tulips and daffodils.

    So, that’s all man-made hybriding, so I get that it can happen. But man-oh-man, that first fish that sprouted lungs and crawled out on dry land. Hmmmmmmmm………..

  7. Wow, Mary! That’s some heavy-duty thinking, lady. But I’m agreeing with everything you say. And your bottle-neck theory really played out during the Egyptian Pharaohs’ time. Those rulers were all caught in a huge bottle-neck of their own making.

    Sounds like your new story is lots of fun. I love it when our characters bicker then kiss and make up.

  8. i cant wait to read it hope soon i am sure it will be just as good as the rest of them i have read.

  9. So have you heard about the Neanderthal bones they did genetic analysis on and now they think MAN shares some genetic material with Neanderthal man. I just sort of want to say….so what?

    The point please?
    And exactly how many of my tax dollars were spent doing genetic testing on Neanderthal bones.

    Not that I don’t respect pure science of course. But that whole….cure cancer thing…are you SURE they have all the money I need.

    Priorities people!

  10. hmmmm, very interesting and thought provoking indeed
    so the bottleneck theory must have been negated by god after the flood because there were only two breeding pairs of everything (except people–though they were all related) and how did that work?

    and could noah have really had 2 of every single animal in the world on the ship?
    birds, bugs, lions and tigers and bears, oh my–i mean there are millions of types of animals in the world…and how did he have enough food for them all?
    so god would have had to re-create many of the animals?

    i absolutely believe in god 100% but i question some of the things in the bible
    don’t shoot me down….i’m really at a point in my life where i’m really searching for what the truth is…
    i know you are a strong believer mary and montanna rose cleared up issues in my mind about men being the head of the household…but i have so many questions

    and i know i kind of got on a tangent here…and maybe it’s not the right place to voice my questions…but i’m on that quest and i just can’t help but ask people who i feel have “it” figured out

  11. I’ve kind of wondered if Noah is just the only one whose story got told. Maybe God saved people here and there. In Africa. In North American. In Asia.
    Besides, why oh why didn’t Noah swat the two mosquitoes, what a missed opportunity.

  12. I don’t think Noah collected two mosquitoes. I’m sure they flew in uninvited. GRIN. He took 125 year to build a boat in the desert but he wasn’t crazeeee.

  13. “why oh why didn’t Noah swat the two mosquitoes”
    And stomp on the two cockroaches. 😀

    Genetic bottleneck is a new term for me, too, Mary. Thanks for improving my vocabulary today.

  14. I heard one time about … like some little bird. I can’t remember what it was. There were two known to still be in existance, on the verge of extinction and they were a father and daughter (was this a bird? Or was it a black footed ferret–good thing I write fiction for a living so I can make this up)
    Anyway, the point was, even if they could get babies, they’d be so highly apt to have disabilities because of the genetic similarity that they weren’t even trying to breed them.

  15. AND, weren’t the Czar’s all bleeders?
    AND, didn’t the regency period in England, where everyone had to marry other lords and ladies, have a terrible infertility rate?
    AND, the white tigers in the Omaha Henry Doorley Zoo, there was something with them. They … FOUND some white tiger that wasn’t related to any of them and it was a HUGE deal because almost all of them had–some disease that they all caught because they were all so inbred.

    Or no, that might be black footed ferrets again. I know those ferrets did something weird.

  16. lol mary…if only we lived a little closer…you’d be the right gal for me to sit next to in church 🙂
    here it seems it’s either catholic or born again–straight laced the bible is black and white and straight from the mouth of god with no exceptions or modifications to the story…and no funnies about it either!

  17. Hmmmm! I thought all men were Neanderthal’s anyways, like Belle’s Anthony! Great post Mary, you can’t help but wonder how much money was spent to find this out!

  18. I think we’d do well together, Tabitha. God gave us the gift of laughter.

    I should have given Anthony a protruding forehead. He deserved it.

    Margaret, go back to work. except, uh…don’t you have to think when you write? I think you’re supposed to, girl.

  19. The black footed ferret population was down to 18 only 7 of which they could use for a breeding program. They were headed for extinction because they ate prairie dogs which ranchers had worked to eradicate. They started reintroducing them in 1996 and they are slowly establishing wild populations. Since 1985 the captive breeding program has produced 7,000 kits. All are descended from the original 7. They are the most endangered animal in the US.

    As for animals that are examples of evolution, it takes thousands and millions of years for species to change. Man hasn’t been watching and recording that long. Two transitional species that show how evolution happens are the northern snakehead fish and the mudskipper. They are both fish, but have primitive lungs and can breath air. They can walk on their fins which they use like legs. These “amphibious” fish are a good example of how life evolved to move from the water to land.
    It takes thousands of years for a shift to take place. A genetic mutation will result in a slight difference. If that difference has an advantage for survival, that individual is likely to survive and pass on its genes. Over many thousands of generations, that gene becomes more and more prevalent and a different type of creature develops. Adaptability does play a big part and has a genetic link.
    The finches in the Galapagos are a good example of this. They are similar in size and coloring, but live on islands which are far enough apart to have kept the populations apart. Over the years, the birds on each island have developed a different sized beak suited to the foods available on the island.
    It is a slow process which is why when we look at the fossil record, the changes have taken millions of years.

    We are taught we are made in the image and likeness of God. Adam and Eve were thrown out of the Garden of Eden. I believe this BUT… It is rather conceited for us to think of God being like us. I feel our souls are the image and likeness of God. The Garden Of Eden could have been part of Heaven. When Adam and Eve were thrown out of the Garden, they were souls cast out to inhabit corporeal bodies which existed on Earth. We spend our lives proving we are worthy to rejoin God at that other level.

    Most scientists believe strongly in their science and the workings of nature. Many of them will be the first to tell you that after studying and seeing all that is around us how can one not believe in miracles and a wondrous being watching over us all.
    Religion and true scientific study are not mutually exclusive.

  20. I’m with Tracy regarding why Noah didn’t swat the mosquitos and cockroaches. I wish he had swatted the two spiders as well.

    Cindy W.


  21. Sorry to be getting here so later today, Mary. Had trouble logging on before. Great post. God has His hand in everything, no matter who believes what on how/when it started. I know there are evolutions that depend on environment and need…e.g. Patricia’s mention of snakefish and mudskippers, but I don’t think there is any evidence (if so I haven’t heard it) of one species changing into another e.g. humans supposed to have been semi/nonhuman apes at one point.

    As for Noah, I don’t see any reason at all for snails LOL. oxoxoxox

  22. Ah, Patricia, there’s my girl.
    And how about giraffes. Don’t you suppose the ones with the long necks survived because they could reach food? So the longer the neck, the longer necked babies they had, since they thrived.

    How do you explain sumo wrestlers.
    Someone take that.

  23. I read somewhere that mosquitoes, filled with blood, are a top notch protein source for many birds. So, okay, FINE! I don’t like it but WHATEVER!!!

    So, bees, honey. I get that. Cockroaches, well they’re something on the food chain I guess. But what about wasps. What do wasps do?

    What exactly would fall through nature’s cracks if there were no wasps.

    I’ve given this considerable thought.

  24. I’m glad you finally brought wasps into the equation. Can’t stand them.

    As for the other stuff, I’ve always been fascinated by geology, but the evolution stuff leaves me cold. I like the way you think. I figure a lot of those questions I can put on a list to ask when I get to heaven – except I won’t CARE anymore, then! 😀

    Now, can we get back to your hero and heroine arguing about fossils and then kissing? 🙂 I remember “back in the day,” when I first started reading Inspirational Fiction, there was VERY LITTLE kissing or PDA of any kind. I like the new Christian Fiction.

    Plus, if there isn’t SOME PDA, then we won’t have a bottle neck, but extinction, like the Shakers… I’m just sayin’

  25. Here’s the first kiss. He just found her. Trapped in a deep pit where she’d climbed down to look for fossils. Left there, stranded, her ladder pulled up, by some unknown stalker.

    I have to get—get—out. Let me go.”
    She was babbling.
    It occurred to him that the right thing to do here was slap her. That’d clear her thinking. Give her a bit of fight, too. It had worked with Ethan years ago. Sort of.
    It’d been more of a punch honestly.
    And now that he thought of it, it hadn’t worked well at all. So…since she was too soft to slap, and sure as certain to soft to punch. He just couldn’t do it. “You’ve got to get ahold of yourself.” Pulling her close, he added, “My name is Rafe. Can you say that?”
    She’d said ladder enough times. “Let’s go.”
    “No!” He gripped her shoulders. “You say my name or we’re not going. You need to calm down. We’re going to be fine, but not if you shake so hard you fall off this ladder.”
    “I’m Rafe.” He shook her hard. “Say it. Prove to me you’ve got the guts to hang on and climb out of this pit.”
    “R—Rafe.” A long slow breath lifted her shoulders. “Rafe. I’m sorry…Rafe. I’m so scared. It’s so dark. I couldn’t get out. My—my Rafe I couldn’t find my Rafe—uh—rope. Rope. I need to get out and I—I—”
    “Stop.” Slapping her just wouldn’t do.
    So he kissed her.

  26. Amen.
    Oh, and nobody took sumo wrestlers. I was waiting for someone’s insight on that 🙂 Maybe they are just a special category of ewwww.

  27. Sumo wrestlers are strictly a man made variation just like size 0 anorexic models.

    I was going to use giraffes in my examples, but didn’t. Your reasons were correct. Any advantage for survival usually takes precedence unless man in his infinite wisdom interferes. Man has taken many genetic mutations that are not beneficial and inbred them for specialty animals that probably wouldn’t survive in nature. We have a tendency for miniature animals – horses and cows come to mind – that really have not much use except as curiosities.

    Hope everyone has a great week.

  28. Wasps are actually predators. Many hunt spiders and caterpillars. Fascinating to watch, but not pleasant. The spiders they paralyze and put into a chamber. They lay an egg on it and seal the chamber. When the egg hatches, the spider is the food source for the larvae. A different variety of wasp lay they eggs on caterpillars. When the eggs hatch, the larvae attach themselves to the living caterpillar and basically suck out nutrition. The larvae usually mature before the caterpillar dies.
    Everything has a place even if we don’t like the creature. The rattlesnake roundups are the perfect example. Thousands of snakes are taken out of the environment by man every year. As a result, the jackrabbit (their main food source) population explodes. The rabbits over run the grazing land, dig more holes and eat too much, impacting the cattle grazing. As a result of rabbit overpopulation, the snake population will increase over the years to balance it off. If we left the snakes alone, nature would keep things in balance and you would have a regular population cycle of the snakes and rabbits. It is the same for most predator/prey species. That brings us back to the black footed ferret which suffered from this kind of interference.

  29. Mary,
    Sorry I’m late. This is facinating to me. I read John Clayton’s “Does God Exist”. He’s an avid athiest turned Christian who tried to disprove the bible and only ended up proving it. Now he spends his life and knowledge educating people on the truths in life. On his site you can find the odds of a big bang happening, the odds of a dna sequence to life, the probability of an ape evolving into a human, etc… He uses modern science and it’s knowledge to prove or disprove theories.

  30. I am a Biologist from Philadelphia; I stumbled on this site by accident and read your article. The answer is: viruses and bacteria. (In response to things that have evolved since we have been aware of evolution.) A multitude of viruses and bacteria, notably those that use a human host, have evolved not just within the span of time since Darwin made his initial publications – roughly 150 years ago – but within our lifetimes. Hence, many hostile bacterial strains today are resistant to penicillin, and erythromycin is now the more commonly prescribed antibiotic. In addition, just within the last two years we saw the H1N1 “Swine Flu” virus – an evolved permutation of what we think of as the “standard” flu virus.

    Disease causing organisms, because they are so much simpler than higher life forms like dogs or cats (which have also shown evolution within the last 150 years, granted that it was guided by humans) evolve much more quickly by comparison, and so they are one of our best examples of the process as it happens right now in an easily observable time frame. This is why doctors have such a struggle combating our more virulent diseases, and why most diseases have not simply been wiped from the face of the earth – they simply evolve into a more potent form, often within a handful of years or even less…

    Just thought I’d answer your question. All the best.

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