… lived during the “bottleneck” in human population about 70,000 years ago?
I read just now that it was about 2,000, so I checked with TATE and they said 1,000-10,000.
But is there really any good evidence for this?
And if the people coming out of Africa interbred with Neanderthals and others around the World, does it even make sense to talk about a single population living in Africa?
The Rev Dodgson said:
… lived during the “bottleneck” in human population about 70,000 years ago?I read just now that it was about 2,000, so I checked with TATE and they said 1,000-10,000.
But is there really any good evidence for this?
And if the people coming out of Africa interbred with Neanderthals and others around the World, does it even make sense to talk about a single population living in Africa?
I dunno. You didn’t include links to your research.
roughbarked said:
The Rev Dodgson said:
… lived during the “bottleneck” in human population about 70,000 years ago?I read just now that it was about 2,000, so I checked with TATE and they said 1,000-10,000.
But is there really any good evidence for this?
And if the people coming out of Africa interbred with Neanderthals and others around the World, does it even make sense to talk about a single population living in Africa?
I dunno. You didn’t include links to your research.
That’s because I want alternative views on the question, but here is a link anyway:
https://en.wikipedia.org/wiki/Main_Page
hth.
More importantly, weren’t there like just 2 at the time of the wet bottleneck 4500 years ago¿
SCIENCE said:
More importantly, weren’t there like just 2 at the time of the wet bottleneck 4500 years ago¿
would have been grim if they didn’t like each other.
JudgeMental said:
SCIENCE said:More importantly, weren’t there like just 2 at the time of the wet bottleneck 4500 years ago¿
would have been grim if they didn’t like each other.
I thought SCIENCE was referring to:
Once before the world began
God was sitting in the sky
He began to get some mud together
O I wonder why
First he made a man
And then he made a woman
Mr. Adam and miss Eve
They began to be quite good friends
As I can well believe
… but wasn’t that about 6000 years ago?
allegedly.
JudgeMental said:
SCIENCE said:More importantly, weren’t there like just 2 at the time of the wet bottleneck 4500 years ago¿
would have been grim if they didn’t like each other.
Apparently, there was 8 people on Noah’s ark, married couples, so presumably at least a couple of them liked each other.
captain_spalding said:
JudgeMental said:
SCIENCE said:
More importantly, weren’t there like just 2 at the time of the wet bottleneck 4500 years ago¿
would have been grim if they didn’t like each other.
Apparently, there was 8 people on Noah’s ark, married couples, so presumably at least a couple of them liked each other.
We apologise for being religiously uninformed and ignorant but claim that it’s well within the engineering safety factor so it’s all good.
SCIENCE said:
captain_spalding said:
JudgeMental said:
would have been grim if they didn’t like each other.
Apparently, there was 8 people on Noah’s ark, married couples, so presumably at least a couple of them liked each other.
We apologise for being religiously uninformed and ignorant but claim that it’s well within the engineering safety factor so it’s all good.
I’ve always been bothered by questions about the state of naval architecture and the state of the science of ship stability in Noah’s day.
Either there was more in the plans for that ark than the Bible lets on, or he pulled off one of the biggest flukes of all time.
SCIENCE said:
captain_spalding said:
JudgeMental said:
would have been grim if they didn’t like each other.
Apparently, there was 8 people on Noah’s ark, married couples, so presumably at least a couple of them liked each other.
We apologise for being religiously uninformed and ignorant but claim that it’s well within the engineering safety factor so it’s all good.
Looks like I got it wrong as well.
Clearly Noah and family are not Adam & Eve, so maybe your 4500 years is about right.
roughbarked said:
I dunno. You didn’t include links to your research.
Sorry we didn’t do this research but here’s a link to some regardless.
An order of magnitude range is pretty precise considering the inherent uncertainty in these studies.
It seems H sap sap was always much more numerous than Neanderthals, Denisovians or “unknown antique African sapiens subspecies”. Maybe (and I’m speculating as a lay person) the other groups also went through a bottleneck if it was due to a global climate event or something.
Should be noted that there have been papers that re-evaluate the evidence and suggest that the genetic evidence of bottlenecks could be equivalent to other changes. I know enough about the topic to understand the arguments and the evidence, but not enough to have a worthwhile opinion on which is the stronger argument.
https://academic.oup.com/mbe/article/17/1/2/975516
https://academic.oup.com/mbe/article/29/7/1851/1070885
The Rev Dodgson said:
roughbarked said:
The Rev Dodgson said:
… lived during the “bottleneck” in human population about 70,000 years ago?I read just now that it was about 2,000, so I checked with TATE and they said 1,000-10,000.
But is there really any good evidence for this?
And if the people coming out of Africa interbred with Neanderthals and others around the World, does it even make sense to talk about a single population living in Africa?
I dunno. You didn’t include links to your research.
That’s because I want alternative views on the question, but here is a link anyway:
https://en.wikipedia.org/wiki/Main_Page
hth.
:)
captain_spalding said:
SCIENCE said:captain_spalding said:
Apparently, there was 8 people on Noah’s ark, married couples, so presumably at least a couple of them liked each other.
We apologise for being religiously uninformed and ignorant but claim that it’s well within the engineering safety factor so it’s all good.
I’ve always been bothered by questions about the state of naval architecture and the state of the science of ship stability in Noah’s day.
Either there was more in the plans for that ark than the Bible lets on, or he pulled off one of the biggest flukes of all time.
All it had to do was float, it didnt need to get uderway.
Peak Warming Man said:
captain_spalding said:
SCIENCE said:We apologise for being religiously uninformed and ignorant but claim that it’s well within the engineering safety factor so it’s all good.
I’ve always been bothered by questions about the state of naval architecture and the state of the science of ship stability in Noah’s day.
Either there was more in the plans for that ark than the Bible lets on, or he pulled off one of the biggest flukes of all time.
All it had to do was float, it didnt need to get uderway.
All it had to do was float the right way up for forty days and forty nights, without (apparently) any means of propulsion or steering, in the middle of a storm that lasted nearly six weeks.
Achieving that would require a bit more planning than ‘Make for yourself an ark of gopher wood. You shall make the ark with compartments and smear pitch on it, both inside and out. Now this is how you shall make it: the length of the ark 300 cubits, its breadth 50 cubits, and its height 30 cubits’.
captain_spalding said:
Peak Warming Man said:
captain_spalding said:I’ve always been bothered by questions about the state of naval architecture and the state of the science of ship stability in Noah’s day.
Either there was more in the plans for that ark than the Bible lets on, or he pulled off one of the biggest flukes of all time.
All it had to do was float, it didnt need to get uderway.
All it had to do was float the right way up for forty days and forty nights, without (apparently) any means of propulsion or steering, in the middle of a storm that lasted nearly six weeks.
Achieving that would require a bit more planning than ‘Make for yourself an ark of gopher wood. You shall make the ark with compartments and smear pitch on it, both inside and out. Now this is how you shall make it: the length of the ark 300 cubits, its breadth 50 cubits, and its height 30 cubits’.
And the lion shall lay down with the lamb.
captain_spalding said:
All it had to do was float the right way up for forty days and forty nights, without (apparently) any means of propulsion or steering, in the middle of a storm that lasted nearly six weeks.
Got dem feels tho’.
The Rev Dodgson said:
… lived during the “bottleneck” in human population about 70,000 years ago?I read just now that it was about 2,000, so I checked with TATE and they said 1,000-10,000.
But is there really any good evidence for this?
And if the people coming out of Africa interbred with Neanderthals and others around the World, does it even make sense to talk about a single population living in Africa?
Through the ages, there have been many bottlenecks for living creatures, with mass extinctions being the most extreme. The Toba eruption, which occurred about 70,000 years ago is one such event that influenced human genetic diversity, yet in Africa there is considerable diversity in populations of the San peoples or Bushmen of the southern portion of the country, thereby indicating that there were pockets where the aftereffects of the Toba eruption were less severe and more survivable.
Some animals also show signs of a bottleneck during this period, which is not unusual especially for those with limited distribution where local catastrophic conditions can greatly reduce populations, which happens in various parts of the world at different times. However, genetic diversity varies greatly between species which again illustrates the fickle nature of these dramatic events and their effect on different species in different places.
Regarding Homo sapiens survival during this period there was certainly a considerable reduction in population size, but people were distributed far and wide, plus there were several different Homo species surviving at the same time that only disappeared after we arrived in their territory and well after the Toba eruption.
I suspect that the Toba eruption like other catastrophic events generated advantages (maybe a more advanced cognitive ability) in our species, permitting a few populations with a limited genetic diversity, to develop and prosper to conquer the world (out of Africa) along with other Homo species.
captain_spalding said:
SCIENCE said:captain_spalding said:
Apparently, there was 8 people on Noah’s ark, married couples, so presumably at least a couple of them liked each other.
We apologise for being religiously uninformed and ignorant but claim that it’s well within the engineering safety factor so it’s all good.
I’ve always been bothered by questions about the state of naval architecture and the state of the science of ship stability in Noah’s day.
Either there was more in the plans for that ark than the Bible lets on, or he pulled off one of the biggest flukes of all time.
I heard he bought the plans for the ark from some guy named Gilgamesh
for a few shekels and a goat
Ogmog said:
captain_spalding said:
SCIENCE said:We apologise for being religiously uninformed and ignorant but claim that it’s well within the engineering safety factor so it’s all good.
I’ve always been bothered by questions about the state of naval architecture and the state of the science of ship stability in Noah’s day.
Either there was more in the plans for that ark than the Bible lets on, or he pulled off one of the biggest flukes of all time.
I heard he bought the plans for the ark from some guy named Gilgamesh
for a few shekels and a goat
Interesting, thanks for that.
An ark is a box
Not a boat
Peak Warming Man said:
Ogmog said:
captain_spalding said:I’ve always been bothered by questions about the state of naval architecture and the state of the science of ship stability in Noah’s day.
Either there was more in the plans for that ark than the Bible lets on, or he pulled off one of the biggest flukes of all time.
I heard he bought the plans for the ark from some guy named Gilgamesh
for a few shekels and a goat
Interesting, thanks for that.
Early interest in the Epic of Gilgamesh was almost exclusively on account of the flood story from Tablet XI. It attracted enormous public attention and drew widespread scholarly controversy, while the rest of the epic was largely ignored. Most attention towards the Epic of Gilgamesh in the late nineteenth and early twentieth centuries came from German-speaking countries, where controversy raged over the relationship between Babel und Bibel (“Babylon and Bible”).
In January 1902, the German Assyriologist Friedrich Delitzsch gave a lecture at the Sing-Akademie zu Berlin before the Kaiser and his wife, in which he argued that the Flood story in the Book of Genesis was directly copied from the Epic of Gilgamesh. Delitzsch’s lecture was so controversial that, by September 1903, he had managed to collect thousands of articles and pamphlets criticizing this lecture about the Flood another about the relationship between the Code of Hammurabi and the biblical Law of Moses. The Kaiser distanced himself from Delitzsch and his radical views and by the fall of 1904, Delitzsch was reduced to giving his third lecture in Cologne and Frankfurt am Main rather than in Berlin. The putative relationship between the Epic of Gilgamesh and the Hebrew Bible later became a major part of Delitzsch’s argument in his 1920–21 book Die große Täuschung (The Great Deception) that the Hebrew Bible was irredeemably “contaminated” by Babylonian influence and that only by eliminating the human Old Testament entirely could Christians finally believe in the true, Aryan message of the New Testament.
The Rev Dodgson said:
… lived during the “bottleneck” in human population about 70,000 years ago?I read just now that it was about 2,000, so I checked with TATE and they said 1,000-10,000.
But is there really any good evidence for this?
And if the people coming out of Africa interbred with Neanderthals and others around the World, does it even make sense to talk about a single population living in Africa?
There is clear evidence for this. The genetics of modern humans in continents other than Africa (and that includes Australian Aborigines) shows a similarity that dates back to about 70,000 BC. This does not include Neanderthals, who left Africa much earlier. My knowledge comes from a TV documentary rather than from scientific research.
The original evidence was mitochondrial, ie. Along the female genetic lineage only. I don’t know off hand if that’s been expanded to full genomes. Let’s look up Google Scholar.
First hit (same article two links)
https://royalsocietypublishing.org/doi/abs/10.1098/rspb.2009.1473
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2842629/
Evidence that two main bottleneck events shaped modern human genetic diversity
W. Amos* and J. I. Hoffman
There is a strong consensus that modern humans originated in Africa and moved out to colonize the world approximately 50 000 years ago. During the process of expansion, variability was lost, creating a linear gradient of decreasing diversity with increasing distance from Africa.
Immediately following a sharp population decline, rare alleles are lost faster than heterozygosity, creating a transient excess of heterozygosity relative to allele number, a feature that is used by Bottleneck to infer historical events. We find evidence of two primary events, one ‘out of Africa’ and one placed around the Bering Strait, where an ancient land bridge allowed passage into the Americas.
That article doesn’t tell us much about either dates or numbers, so search back earlier.
Cavalli-Sforza L. L., Piazza A., Menozzi (1994) History and geography of human genes Princeton, NJ: Princeton University Press
Now this is a book. So may not be easily available online. Try https://books.google.com.au/books?hl=en&lr=&id=FrwNcwKaUKoC&oi=fnd&pg=PP1&dq=info:laDBa9_mAZIJ:scholar.google.com/&ots=Hp3TQcHy73&sig=uH-dz1y7YBXHZIbZYuuH2w8S0wg&redir_esc=y#v=onepage&q&f=false
That book isn’t the answer either. It’s a multivariate analyses based on all sorts of properties such as cranial shape. From the book. Dang, won’t cut and paste from Google books on Android.
Anyway, earliest fossil ancient modern humans are 95,000 years at Nazareth. 67,000 years in China. 55,000 years in Australia. 35,000 years in America.
I seem to have reached a dead end here. Let’s try a different tack.
https://www.annualreviews.org/doi/abs/10.1146/annurev.genet.41.110306.130407
Chapter: Speciation and Out-of-Africa bottlenecks. Behind a paywall.
Keep trying.
https://www.science.org/content/article/how-we-lost-our-diversity
With the recent publication of a large data set of 763 microsatellite markers—short stretches of DNA that are repeated in the genome—from 53 populations in the Human Genome Diversity Project, evolutionary geneticists William Amos and Joe Hoffman of the University of Cambridge in the United Kingdom had enough genomic data to test both models. Using a software program called BOTTLENECK.
No – that’s just a summary of the paper I quoted earlier.
Many scientists have suggested that those who left Africa went through a bottleneck, where only a small number of individuals had offspring.
“Many scientists”, now that’s frikkin’ useless.
https://www.ox.ac.uk/research/genetic-studies-reveal-diversity-early-human-populations-%E2%80%93-and-pin-down-when-we-left-africa
By interrogating the distribution of mutations between African and non-African genomes, two of the papers just about agree that the genetic bottleneck caused by the migration out of Africa occurred roughly 60,000 years ago.
https://www.nature.com/articles/325031a0
Mitochondrial DNA and human evolution
Rebecca L. Cann, Mark Stoneking & Allan C. Wilson
From Nature magazine. 1987.
Behind a paywall.
I’m not getting anywhere. I’m beginning to suspect that the work you quote was first published in a conference, rather than in a journal accessible to Google Scholar.
The authors reconstruct the history of our evolution by focusing on genetic divergence among human groups. Using genetic information accumulated over the last fifty years, they examined over 110 different inherited traits, such as blood types, HLA factors, proteins, and DNA markers, in over eighteen hundred, primarily aboriginal, populations. By mapping the worldwide geographic distribution of the genes, the scientists are now able to chart migrations and, in exploring genetic distance, devise a clock by which to date evolutionary history.
Moll: go to this web page to get past paywalls for research papers:
https://sci-hub.zidianzhan.net/
Start again with Wikipedia.
https://en.m.wikipedia.org/wiki/Early_human_migrations
The so-called “recent dispersal” of modern humans took place about 70–50,000 years ago. It is this migration wave that led to the lasting spread of modern humans throughout the world.
A small group from a population in East Africa, bearing mitochondrial haplogroup L3 and numbering possibly fewer than 1,000 individuals, crossed the Red Sea strait at Bab-el-Mandeb, to what is now Yemen, after around 75,000 years ago.
So references 58 to 62 look promising. Try 61.
61 Zhivotovsky; Rosenberg, NA; Feldman, MW; et al. (2003). “Features of Evolution and Expansion of Modern Humans, Inferred from Genomewide Microsatellite Markers”. American Journal of Human Genetics. 72 (5): 1171–1186. doi:10.1086/375120. PMC 1180270. PMID 12690579.
62 Stix, Gary (2008). “The Migration History of Humans: DNA Study Traces Human Origins Across the Continents”. Scientific American.
OK, so publicised in Scientific American, which is how it became so well known.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1180270/
Sub-saharan not middle east, but we’re getting closer.
The hunter-gatherer populations of sub-Saharan Africa show a minor, very recent expansion in size, although it is not statistically significant. Table 2 indicates that the sub-Saharan African farming populations expanded earlier than did the populations of Eurasia and East Asia and that the effective size of the former populations prior to expansion was rather small, <2,000, or a census size of perhaps 6,000 by the “triple rule” of Cavalli-Sforza et al. (1994).
One possibility is that, rather than a single exit from Africa with subsequent migrations to other regions, a few different waves of ancient migration out of Africa might have occurred in the peopling of the world, one of which was to Oceania; this is in agreement with the suggestion of Jin et al. (1999). Alternatively, with a single wave of migration, this distribution of private alleles could be explained by long-term isolation of these Oceanic populations.
So reference 61 does not have the information we want. What about Reference 62?
https://www.scientificamerican.com/article/the-migration-history-of-humans/
“Fifty or sixty thousand years ago a small band of Africans—a few hundred or even several thousand—crossed the strait in tiny boats, never to return.”
The information we want is there. In Scientific American in 2008. Where did they get it from?
In February two papers, one in Science, the other in Nature, reported the largest surveys to date of human diversity.
Noah A. Rosenberg of the University of Michigan at Ann Arbor and lead author of the Nature paper.
The Nature paper is at
https://deepblue.lib.umich.edu/bitstream/handle/2027.42/62552/nature06742.pdf?sequence=1
This paper gives great graphs of modern human ancestry. But does not give any information on the number of people who left Africa.
So our last hope for the Scientific original source is a paper in Science magazine from February 2008, authors unknown.
The Science article is here. website femininebeauty?
http://femininebeauty.info/f/science.human.genome.variation.2008.pdf
Worldwide Human Relationships Inferred from Genome-Wide Patterns of Variation
Jun Z. Li, 1,2*† Devin M. Absher, 1,2* Hua Tang, 1 Audrey M. Southwick, 1,2 Amanda M. Casto, 1
Sohini Ramachandran, 4 Howard M. Cann, 5 Gregory S. Barsh,1,3 Marcus Feldman, 4‡
Luigi L. Cavalli-Sforza,
Not there.
The evidence for how many people migrated out of Africa seems to appear in Scientific American in the year 2008 without any hard published evidence to back it up.
It may be false.
mollwollfumble said:
Start again with Wikipedia.https://en.m.wikipedia.org/wiki/Early_human_migrations
The so-called “recent dispersal” of modern humans took place about 70–50,000 years ago. It is this migration wave that led to the lasting spread of modern humans throughout the world.
A small group from a population in East Africa, bearing mitochondrial haplogroup L3 and numbering possibly fewer than 1,000 individuals, crossed the Red Sea strait at Bab-el-Mandeb, to what is now Yemen, after around 75,000 years ago.
So references 58 to 62 look promising. Try 61.
61 Zhivotovsky; Rosenberg, NA; Feldman, MW; et al. (2003). “Features of Evolution and Expansion of Modern Humans, Inferred from Genomewide Microsatellite Markers”. American Journal of Human Genetics. 72 (5): 1171–1186. doi:10.1086/375120. PMC 1180270. PMID 12690579.
62 Stix, Gary (2008). “The Migration History of Humans: DNA Study Traces Human Origins Across the Continents”. Scientific American.
OK, so publicised in Scientific American, which is how it became so well known.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1180270/
Sub-saharan not middle east, but we’re getting closer.
The hunter-gatherer populations of sub-Saharan Africa show a minor, very recent expansion in size, although it is not statistically significant. Table 2 indicates that the sub-Saharan African farming populations expanded earlier than did the populations of Eurasia and East Asia and that the effective size of the former populations prior to expansion was rather small, <2,000, or a census size of perhaps 6,000 by the “triple rule” of Cavalli-Sforza et al. (1994).
One possibility is that, rather than a single exit from Africa with subsequent migrations to other regions, a few different waves of ancient migration out of Africa might have occurred in the peopling of the world, one of which was to Oceania; this is in agreement with the suggestion of Jin et al. (1999). Alternatively, with a single wave of migration, this distribution of private alleles could be explained by long-term isolation of these Oceanic populations.
So reference 61 does not have the information we want. What about Reference 62?
https://www.scientificamerican.com/article/the-migration-history-of-humans/
“Fifty or sixty thousand years ago a small band of Africans—a few hundred or even several thousand—crossed the strait in tiny boats, never to return.”
The information we want is there. In Scientific American in 2008. Where did they get it from?
In February two papers, one in Science, the other in Nature, reported the largest surveys to date of human diversity.
Noah A. Rosenberg of the University of Michigan at Ann Arbor and lead author of the Nature paper.
The Nature paper is at
https://deepblue.lib.umich.edu/bitstream/handle/2027.42/62552/nature06742.pdf?sequence=1
This paper gives great graphs of modern human ancestry. But does not give any information on the number of people who left Africa.
So our last hope for the Scientific original source is a paper in Science magazine from February 2008, authors unknown.
The Science article is here. website femininebeauty?
http://femininebeauty.info/f/science.human.genome.variation.2008.pdf
Worldwide Human Relationships Inferred from Genome-Wide Patterns of Variation
Jun Z. Li, 1,2*† Devin M. Absher, 1,2* Hua Tang, 1 Audrey M. Southwick, 1,2 Amanda M. Casto, 1
Sohini Ramachandran, 4 Howard M. Cann, 5 Gregory S. Barsh,1,3 Marcus Feldman, 4‡
Luigi L. Cavalli-Sforza,Not there.
The evidence for how many people migrated out of Africa seems to appear in Scientific American in the year 2008 without any hard published evidence to back it up.
It may be false.
I might be wrong, but wasn’t this thread about how many people survived the ‘bottleneck’ not how many left Africa at the time?
mollwollfumble said:
The Rev Dodgson said:
… lived during the “bottleneck” in human population about 70,000 years ago?I read just now that it was about 2,000, so I checked with TATE and they said 1,000-10,000.
But is there really any good evidence for this?
And if the people coming out of Africa interbred with Neanderthals and others around the World, does it even make sense to talk about a single population living in Africa?
There is clear evidence for this. The genetics of modern humans in continents other than Africa (and that includes Australian Aborigines) shows a similarity that dates back to about 70,000 BC. This does not include Neanderthals, who left Africa much earlier. My knowledge comes from a TV documentary rather than from scientific research.
The original evidence was mitochondrial, ie. Along the female genetic lineage only. I don’t know off hand if that’s been expanded to full genomes. Let’s look up Google Scholar.
First hit (same article two links)
https://royalsocietypublishing.org/doi/abs/10.1098/rspb.2009.1473
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2842629/Evidence that two main bottleneck events shaped modern human genetic diversity
W. Amos* and J. I. HoffmanThere is a strong consensus that modern humans originated in Africa and moved out to colonize the world approximately 50 000 years ago. During the process of expansion, variability was lost, creating a linear gradient of decreasing diversity with increasing distance from Africa.
Immediately following a sharp population decline, rare alleles are lost faster than heterozygosity, creating a transient excess of heterozygosity relative to allele number, a feature that is used by Bottleneck to infer historical events. We find evidence of two primary events, one ‘out of Africa’ and one placed around the Bering Strait, where an ancient land bridge allowed passage into the Americas.
That article doesn’t tell us much about either dates or numbers, so search back earlier.
Cavalli-Sforza L. L., Piazza A., Menozzi (1994) History and geography of human genes Princeton, NJ: Princeton University Press
Now this is a book. So may not be easily available online. Try https://books.google.com.au/books?hl=en&lr=&id=FrwNcwKaUKoC&oi=fnd&pg=PP1&dq=info:laDBa9_mAZIJ:scholar.google.com/&ots=Hp3TQcHy73&sig=uH-dz1y7YBXHZIbZYuuH2w8S0wg&redir_esc=y#v=onepage&q&f=false
That book isn’t the answer either. It’s a multivariate analyses based on all sorts of properties such as cranial shape. From the book. Dang, won’t cut and paste from Google books on Android.
Anyway, earliest fossil ancient modern humans are 95,000 years at Nazareth. 67,000 years in China. 55,000 years in Australia. 35,000 years in America.
I seem to have reached a dead end here. Let’s try a different tack.
https://www.annualreviews.org/doi/abs/10.1146/annurev.genet.41.110306.130407
Chapter: Speciation and Out-of-Africa bottlenecks. Behind a paywall.
Keep trying.
https://www.science.org/content/article/how-we-lost-our-diversity
With the recent publication of a large data set of 763 microsatellite markers—short stretches of DNA that are repeated in the genome—from 53 populations in the Human Genome Diversity Project, evolutionary geneticists William Amos and Joe Hoffman of the University of Cambridge in the United Kingdom had enough genomic data to test both models. Using a software program called BOTTLENECK.
No – that’s just a summary of the paper I quoted earlier.
Many scientists have suggested that those who left Africa went through a bottleneck, where only a small number of individuals had offspring.
“Many scientists”, now that’s frikkin’ useless.
https://www.ox.ac.uk/research/genetic-studies-reveal-diversity-early-human-populations-%E2%80%93-and-pin-down-when-we-left-africa
By interrogating the distribution of mutations between African and non-African genomes, two of the papers just about agree that the genetic bottleneck caused by the migration out of Africa occurred roughly 60,000 years ago.
https://www.nature.com/articles/325031a0
Mitochondrial DNA and human evolution
Rebecca L. Cann, Mark Stoneking & Allan C. Wilson
From Nature magazine. 1987.Behind a paywall.
I’m not getting anywhere. I’m beginning to suspect that the work you quote was first published in a conference, rather than in a journal accessible to Google Scholar.
The authors reconstruct the history of our evolution by focusing on genetic divergence among human groups. Using genetic information accumulated over the last fifty years, they examined over 110 different inherited traits, such as blood types, HLA factors, proteins, and DNA markers, in over eighteen hundred, primarily aboriginal, populations. By mapping the worldwide geographic distribution of the genes, the scientists are now able to chart migrations and, in exploring genetic distance, devise a clock by which to date evolutionary history.
I wasn’t questioning the date, although it seems there is more variation in the date of the bottleneck than I thought. It was the size of the bottleneck I had in doubt, and it seems there isn’t much reliable evidence for that.
The Rev Dodgson said:
I wasn’t questioning the date, although it seems there is more variation in the date of the bottleneck than I thought. It was the size of the bottleneck I had in doubt, and it seems there isn’t much reliable evidence for that.
I totally agree. Unless the author of the Scientific American article has some private knowledge that we don’t know about, the size doesn’t seem reliable. The private knowledge could be direct scientific measurement by the author, an unpublished article, or a conference paper. Conference papers often don’t get written up in major journals.
> I might be wrong, but wasn’t this thread about how many people survived the ‘bottleneck’ not how many left Africa at the time?
So far as I know, the two are identical. The bottleneck is found in all people who are now out of Africa, but not in any people who are in Africa. There are different bottlenecks in Africa itself. And different migrations out of Africa. But this one migration out of Africa seems top be the largest bottleneck.