Population Histories of the United States Revealed through Fine-Scale Migration

[Jovialis]

The population of the United States is shaped by centuries of migration, isolation, growth, and admixture between ancestors of global origins. Here, we assemble a comprehensive view of recent population history by studying the ancestry and population structure of more than 32,000 individuals in the US using genetic, ancestral birth origin, and geographic data from the National Geographic Genographic Project. We identify migration routes and barriers that reflect historical demographic events. We also uncover the spatial patterns of relatedness in subpopulations through the combination of haplotype clustering, ancestral birth origin analysis, and local ancestry inference. Examples of these patterns include substantial substructure and heterogeneity in Hispanics/Latinos, isolation-by-distance in African Americans, elevated levels of relatedness and homozygosity in Asian immigrants, and fine-scale structure in European descents. Taken together, our results provide detailed insights into the genetic structure and demographic history of the diverse US population.

https://www.cell.com/ajhg/fulltext/S0002-9297(20)30044-6

[Ygorcs]

Interesting! In the population history of the USA what I really found incredibly unique and probably worth studying much more deeply is the unprecedented and almost miraculous population growth that it experienced as early as the 17th century, but particularly in the 18th and early-mid 19th centuries. Even the black enslaved population grew astoundingly in numbers from the early 1700s to the mid 1800s even if the actual number of slaves imported into the USA is estimated to have been not very large (at most 500,000 peolpe). When most of the world experienced "population booms" when they were getting a 0.3% or 0.4% population growth per year, the USA had population growth well above 1.5-2.0% since the 18th century, or else the population numbers it had in the early 1800s could never be explained considering the most reliable estimates for the number of immigrants that came from Europe and Africa to the USA. The death rates must've been particularly low for world standards (why?), but fertility rates in particular must've been incredibly high.

[Angela]

I wanted to refresh my recollection a bit, and here it is:

"The New England colonists included more educated men as well as many skilled farmers, tradesmen and craftsmen. They were mostly farmers and settled in small villages for common religious activity. Shipbuilding, commerce, and fisheries were important in coastal towns. New England's healthy climate (the cold winters killed the mosquitoes and other disease-bearing insects), and abundant food supply resulted in the lowest death rate and highest birth rate of any place in the world (marriage was expected and birth control was not, and a much higher than average number of children and mothers survived).^[5]The eastern and northern frontier around the initial New England settlements was mainly settled by the Yankee descendants of the original New Englanders. Emigration to the New England colonies after 1640 and the start of the English Civil War decreased to less than 1% (about equal to the death rate) in nearly all years prior to 1845. The rapid growth of the New England colonies (total population ≈700,000 by 1790) was almost entirely due to the high birth rate (>3%) and low death rate (<1%) per year.<sup>[6]"

The food was abundant because virtually every family could acquire enough good farm land to feed themselves. Probably 80% of farmers owned their own land. The population density was also much less; less crowding, better hygiene, less spread of disease.

The fact that most of the population lived on self-sufficient farms in self-governing village or town units explains a lot about the predilection of many Americans for small, local government, and their belief in self-reliance.</sup>

[Ygorcs]

Excellent post, Angela. I really doubt the death rates were as low as <1% per year any time before modern medicine, sanitation and technology (in most countries in the world that rate would only be achieved after the 1940s, and even in the USA it was around 1.7% or 17 per thousand in 1900). But I think death rates as low as 3% or even slightly lower than that (very low for the standards of the 17th and 18th century) coupled with unusually large birth rates above 5% per year (the usual birth rate at that time hovered between ~40-45 per thousand) were a really likely scenario, considering all those advantages that you mentioned, and I think the social organization in very small villages scattered over a large territory with lots of farming, pasture and forest between them was perhaps the real trick, because it slowed epidemics down and made for a generally healthier environment. The climate also seems to have played a major role... and modern historians still say that hypotheses about socioeconomic development based on climate are outdated and pseudoscientific. I honestly don't think a climate more conducive to better nutrition and lower spread of diseases will have no impact on how much a given society can potentially develop, at least in pre-modern conditions.

[Angela]

Excellent post, Angela. I really doubt the death rates were as low as <1% per year any time before modern medicine, sanitation and technology (in most countries in the world that rate would only be achieved after the 1940s, and even in the USA it was around 1.7% or 17 per thousand in 1900). But I think death rates as low as 3% or even slightly lower than that (very low for the standards of the 17th and 18th century) coupled with unusually large birth rates above 5% per year (the usual birth rate at that time hovered between ~40-45 per thousand) were a really likely scenario, considering all those advantages that you mentioned, and I think the social organization in very small villages scattered over a large territory with lots of farming, pasture and forest between them was perhaps the real trick, because it slowed epidemics down and made for a generally healthier environment. The climate also seems to have played a major role... and modern historians still say that hypotheses about socioeconomic development based on climate are outdated and pseudoscientific. I honestly don't think a climate more conducive to better nutrition and lower spread of diseases will have no impact on how much a given society can potentially develop, at least in pre-modern conditions.

I agree.

Something which the paper points out but which most people don't know about the U.S., is that certain ethnic groups settled in certain areas. The Northeast is not the place to go if you want to get to know a lot of Scandinavians, and you're not going to find a ton on Italians in Oklahoma and Idaho. :)

[matty74]

If you want to find "Scandinavians" you'll have to go to the upper Midwest or parts of the Pacific Northwest. Germans are also heavily represented in the Midwest, especially those who immigrated after 1850. Most of the early immigration to the original colonies (Pennsylvania etc.) came from the Rhineland/Palatinate area wheras those who settled in Chicago, Milwaukee, Minnesota, Iowa and the Dakotas were mainly from northern Germany or east of the Elbe.