Providing a sensible answer is dependent on arriving at a sensible interpretation of the question. I’ll assume that it is aimed at understanding to what degree farming or non-farming lifestyles have had an influence on the selection of genes that you carry. I assume that “farming lifestyle” includes people who don’t actually farm, but obtain food from farmers, one way or another.
On that basis, and assuming you are a typical inhabitant of a society that hasn’t recently engaged in much hunting/gathering (maybe some fishing, but not dominant), I would say that about 1⁄30 of your ancestors were of a farming lifestyle. That is, if you trace back what the selective influences were on your ancestors, about 1⁄30 of it was selection for reproduction in a farming community. I get the 1⁄30 by dividing 300,000 years of homo sapiens into 10,000 years of agriculture.
I don’t think the population sizes at different times, and collapse of the pedigree (some of your ancestors being the same people), make any difference. It might make a difference if the number of children per person varied, since each child is a new object for selection, but I think this may be rather constant until very recent times. And of course, the number of children who survive to reproduce themselves is close to two at all times. (The population has grown over time, but at nowhere near the rate it would if, say, three children per couple survived to reproduce themselves.)
Now, depending on how quick evolution can act, the fact that the 1⁄30 of the selection influence is the most recent1⁄30 could be crucial.
I’ll assume that it is aimed at understanding to what degree farming or non-farming lifestyles have had an influence on the selection of genes that you carry.
This was not my question, but you’re free to answer a different one! :)
Ahh, but without a purpose, how can one tell what the question actually is?
You could be asking about who you get by tracing back births and matings over the last 300,000 years that led to you. But do you then count people more than once if they show up more than once in this back trace?
Or are you really asking where your genetic material came from? It’s quite possible that none of your genetic material came from one of your great-great-great-great-great-great-great-grandfathers. Genes aren’t selected independently to be included or not in sperm or egg, but instead come in larger chunks (I think a few hundred of them), which means that it’s entirely possible for the entire genetic contribution of one “ancestor” to by chance be lost in relatively few generations (of course, that means that some other ancestor contributes more than one might have thought). If you define “ancestor” as “person some of whose genes I have”, then the number of distant ancestors you have is much less than you might have thought.
In the above, I’m tracing back where from a physical point of view the genes came from. But of course, the fact that the genes of some ancestor did not by a physical process result in any genes in you does not imply that you don’t have some of the exact same genes as them—which you may have obtained from some other ancestor. Does that count?
In that case, it’s non-farmers by a good margin. Our ancestry goes back well over a billion years, mostly in species with short generation times. Farming goes back roughly ten thousand years in a single species with a ~25 year generation time.
Now, depending on how quick evolution can act, the fact that the 1⁄30 of the selection influence is the most recent1⁄30 could be crucial.
This is an important insight, if that’s the reason behind the question. If you break one’s genetic heritage into 30 equal slices, 29 of which are hunter-gatherer, one of which is farming, and the last fragment is a rounding error too short for evolution to matter. You’ll likely find that evolution is punctuated by reactions to large changes in what makes for fitness in the environment. The first slice (change from little cooperation and very low cultural adaptations to cooperative hunter-gatherer tribes with some amount of cultural knowledge transfer) likely saw a fair bit of change. The second through 29th slices saw continued adaptation to previous adaptations, but no major disruptions at the evolutionary/genetic level. The 30th slice saw a huge environmental change, and a somewhat different selection pressure.
The most recent 1⁄30 could EASILY have more impact than the 28 10000-year segments before it.
Providing a sensible answer is dependent on arriving at a sensible interpretation of the question. I’ll assume that it is aimed at understanding to what degree farming or non-farming lifestyles have had an influence on the selection of genes that you carry. I assume that “farming lifestyle” includes people who don’t actually farm, but obtain food from farmers, one way or another.
On that basis, and assuming you are a typical inhabitant of a society that hasn’t recently engaged in much hunting/gathering (maybe some fishing, but not dominant), I would say that about 1⁄30 of your ancestors were of a farming lifestyle. That is, if you trace back what the selective influences were on your ancestors, about 1⁄30 of it was selection for reproduction in a farming community. I get the 1⁄30 by dividing 300,000 years of homo sapiens into 10,000 years of agriculture.
I don’t think the population sizes at different times, and collapse of the pedigree (some of your ancestors being the same people), make any difference. It might make a difference if the number of children per person varied, since each child is a new object for selection, but I think this may be rather constant until very recent times. And of course, the number of children who survive to reproduce themselves is close to two at all times. (The population has grown over time, but at nowhere near the rate it would if, say, three children per couple survived to reproduce themselves.)
Now, depending on how quick evolution can act, the fact that the 1⁄30 of the selection influence is the most recent 1⁄30 could be crucial.
This was not my question, but you’re free to answer a different one! :)
Ahh, but without a purpose, how can one tell what the question actually is?
You could be asking about who you get by tracing back births and matings over the last 300,000 years that led to you. But do you then count people more than once if they show up more than once in this back trace?
Or are you really asking where your genetic material came from? It’s quite possible that none of your genetic material came from one of your great-great-great-great-great-great-great-grandfathers. Genes aren’t selected independently to be included or not in sperm or egg, but instead come in larger chunks (I think a few hundred of them), which means that it’s entirely possible for the entire genetic contribution of one “ancestor” to by chance be lost in relatively few generations (of course, that means that some other ancestor contributes more than one might have thought). If you define “ancestor” as “person some of whose genes I have”, then the number of distant ancestors you have is much less than you might have thought.
In the above, I’m tracing back where from a physical point of view the genes came from. But of course, the fact that the genes of some ancestor did not by a physical process result in any genes in you does not imply that you don’t have some of the exact same genes as them—which you may have obtained from some other ancestor. Does that count?
Not every question has to have a purpose! :) Imagine that this is intellectual interest only, at least to me.
No? This question would be trivially easy if you did lol.
No. I personally wanted a literal answer to my literal question.
In that case, it’s non-farmers by a good margin. Our ancestry goes back well over a billion years, mostly in species with short generation times. Farming goes back roughly ten thousand years in a single species with a ~25 year generation time.
The question specified the restriction to humans in the last 300,000 years.
I’m confused about the disagree votes. Which specific sentence do you disagree with?
Note you can now line-item react to highlight specific disagreement!
Very cool!
This is an important insight, if that’s the reason behind the question. If you break one’s genetic heritage into 30 equal slices, 29 of which are hunter-gatherer, one of which is farming, and the last fragment is a rounding error too short for evolution to matter. You’ll likely find that evolution is punctuated by reactions to large changes in what makes for fitness in the environment. The first slice (change from little cooperation and very low cultural adaptations to cooperative hunter-gatherer tribes with some amount of cultural knowledge transfer) likely saw a fair bit of change. The second through 29th slices saw continued adaptation to previous adaptations, but no major disruptions at the evolutionary/genetic level. The 30th slice saw a huge environmental change, and a somewhat different selection pressure.
The most recent 1⁄30 could EASILY have more impact than the 28 10000-year segments before it.