Any conversation that discusses the validity of the Bible and its claims will most likely turn toward Adam and Eve at some point. These two are used as an example of why the Bible cannot be real. So today I will be diving into some questions about Adam and Eve.
Let’s begin by making sure everyone is aware of the story. Adam and Eve, according to the account in Genesis, are the first two people to ever live. Some people think the story of Adam and Eve is literal, others think it is symbolic. Their names mean human and life. I'm not going into the debate over literal or symbolic. This piece is an interesting train of thought. For what follows I will be proceeding as if the story is literal.
God created Adam, and then created Eve because Adam needed a partner. Adam and Eve had two sons Cain and Abel. Cain killed Abel. Adam and Eve had another son named Seth.
The story goes on to mention Cain and Seth getting married. People immediately begin asking where these mysterious wives came from. The answer is that they were Cain and Seth’s sisters.
Wait? What? There were no other people mentioned in the first few chapters of Genesis.
That is true, so we first have to look at how genealogies work in the bible. I won’t go into a full description, that is something I will save for a later post. The important thing to note here is that women are rarely listed in genealogies. Make of that what you will. The few women mentioned in biblical lists are there because of major events or teaching moments. There are daughters who inherit their father’s property because he has no sons, Rahab the woman from Jericho who helped Israel take the city, Ruth the Moabite woman who showed great care for her mother in law, and others.
Back to the children of Adam and Eve. We have no idea how many children they had. We are only ever given the names of three sons, and one of them dies without any heirs. Following the Biblical narrative, everyone in the world today is descended from Adam and Eve. The claim is typically shot down by mentioning that this would involve incest, as brother married sister and so on, which would lead to mutated genetic freaks of children after several generations.
For those who don’t understand why incest is generally a bad idea, look to genetics. Humans carry many different diseases and disorders which are caused by mutations in the human genome. We inherit these mutated genes from our parents, many are dormant. If two people with dormant genetic diseases have a child, that child has a higher chance that the disease actually manifests. Since siblings inherit traits from their parents, they are more likely to share the same traits with each other. If two siblings have kids, these negative traits have a higher chance of affecting the child. To prevent a species from degrading into a mass of genetic slop, a certain number of healthy individuals with different genetic traits are required to keep the population maintained.
Now we get to the main question that I will be tackling today. Could humanity have survived if everyone was descended from just two people? To give me a baseline, I will be referencing two studies.
Using these as my baseline, we have a minimum population to look for. We need 49 pairs of child producing adults who have 2 or less harmful mutations each.
On the face of it, the incest argument is a decent one. If everyone is closely related for the first few generations, that means negative traits will spread rapidly through the population. However we are working off a modern model and trying to apply it to a past event. As any historian will tell you, the way things work today is not necessarily the way they worked in the past. Trying to use a modern model as proof for the past is dangerous at best.
We need to fix our starting point. In the modern world everyone has at least some genetic mutation, not all are negative. However, Adam and Eve would not have had any of these mutations. As the first two people, created by God, they would have possessed a perfect genetic code. This means that their children had no chance of inheriting negative traits. Harmful mutations are not present in the original group, so they must develop before they can be passed on.
The question then becomes, how fast do these traits appear? As generations progressed genetic mutations would eventually pile up, until we arrive at what we have today. So let’s do some math.
As an estimate, let’s assume there is a harmful genetic mutation in every 100 births. Now we know that not every mutation is bad, red hair, lighter skin, etc. For the sake of this topic though we will assume that every mutation is negative. For the next number we will say that every family has six kids, 3 boys and 3 girls. We assume that any person carrying a mutation will pass it on to half of their children.
Using these criteria, I did some excel math. We don’t see a genetic mutation until four generations after Adam and Eve. The total number of people by the 4th generation is 384, which includes the 162 people born in the 4th generation. This means 3 or 4 people in the 4th generation would have a genetic mutation. This is well within the tolerance of 98 people with 1 or 2 mutations each.
Of course this isn’t the end of our story. The biblical narrative also includes Noah and the flood. Noah, his wife, his sons, and their wives are the only people left alive after the flood. We aren’t starting over with just two people this time, but we would be starting with a population that already includes mutations.
If you follow the genealogy lists in the bible, Noah is nine generations after Adam. Noah’s sons and their wives are the next generations. This means we start with three child producing pairs. Of these six people, 2 of them carry a mutation. This time it would only take three generations after Noah’s kids before the population passed 100 people. In the third generation there are 162 births. Out of those 162, 61 of them have a mutation.
If we exclude everyone with a mutation, that still leaves us with 101 people, or 50 child producing pairs who carry no mutations themselves. This is more than enough to start a population with. If we double the rate of mutation in the estimate we end up with 162 people, 122 of which have a mutation. Double the rate again and we get 280 mutations in the population, which is 1.72 mutations per person. This is still within acceptable range for our estimate.
Obviously this all relies on estimates and assumptions, I would love it if someone with more knowledge of these types of models wanted to weigh in, but I hope it serves to show that the entire population of earth could have come from just two people under the right conditions.
About the Author:
Stephen Mayo lives in Montana with his wife, daughter, corgi, and three cats.
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