The discussion centers around a recent study suggesting that human ancestors experienced a significant population bottleneck approximately 900,000 years ago, reducing their numbers to around 1,000 individuals. Participants explore the implications of this finding, the methodologies used in the study, and the potential environmental and evolutionary factors involved. The conversation touches on genetic analysis, fossil records, and historical population dynamics.
Participants express a range of views, with no consensus reached on the implications of the bottleneck, the reliability of the data, or the correlation with global events. Multiple competing interpretations of the findings and their significance remain present in the discussion.
Participants note limitations in the study's assumptions, including the dependence on fossil records and the potential filtering of genetic signals from populations outside Africa. The discussion reflects ongoing uncertainties regarding the historical context of the bottleneck and its broader implications for human evolution.
I wonder what the uncertainties are on that number, or would that number be a lower bound.BWV said:1000 individuals
As I understand it from the description in Arstechnica, this number (about 1300) is the approximate number of individuals that contributed genetically to the population in a way that is reflected to our lineage today. Or, in other words, if you trace the ancestors of any human today back in time, it will eventually contain a subset of only those 1300 individuals. At least, that is how I understand it.Astronuc said:I wonder what the uncertainties are on that number, or would that number be a lower bound.
As I understand it, this bottleneck in the population on the African continent as detected up by the new analysis model is not (yet) correlated with any global change that has been picked up by other means or in other populations. Also, it is not clear to me if the new analysis "on purpose" has filtered out genetic "signals" from populations that already had left Africa around that time but later mixed back into the gene pool (e.g. Neanderthals) or not, but I did get away with a clear understanding this analysis only speaks about the African population at around 900k years ago, meaning if remaining global population had no such bottleneck the cause of an African bottleneck likely has to be fairly local.BWV said:1 MYA had a homo erectus population spread out across Eurasia, so hard to picture a widespread extinction.
if you define ‘speciation’ as a branch where the new organism can no longer create fertile offspring with the old organism (like donkey and horse) - then perhaps some genetic change made a population of early humans no longer able to breed and create fertile offspring with the rest of the population at that time?Filip Larsen said:As I understand it, this bottleneck in the population on the African continent as detected up by the new analysis model is not (yet) correlated with any global change that has been picked up by other means or in other populations. Also, it is not clear to me if the new analysis "on purpose" has filtered out genetic "signals" from populations that already had left Africa around that time but later mixed back into the gene pool (e.g. Neanderthals) or not, but I did get away with a clear understanding this analysis only speaks about the African population at around 900k years ago, meaning if remaining global population had no such bottleneck the cause of an African bottleneck likely has to be fairly local.