scholarly journals Sociogeographic correlates of typological variation in northwestern Bantu gender systems

2022 ◽  
pp. 1-69
Author(s):  
Annemarie Verkerk ◽  
Francesca Di Garbo
Keyword(s):  
Population Size ◽  
Population History ◽  
Bantu Languages ◽  
Explanatory Variables ◽  
Diverse Area ◽  
History Of ◽  
Quantitative Analyses ◽  
Typological Variation ◽  
Language Sample

Abstract This paper investigates the sociolinguistic factors that impact the typology and evolution of grammatical gender systems in northwestern Bantu, the most diverse area of the Bantu-speaking world. We base our analyses on a typological classification of 179 northwestern Bantu languages, focusing on various instances of semantic agreement and their role in the erosion of gender marking. In addition, we conduct in-depth analyses of the sociolinguistics and population history of the 17 languages of the sample with the most eroded gender systems. The sociohistorical factors identified to explain these highly eroded systems are then translated into a set of explanatory variables, which we use to conduct extensive quantitative analyses on the 179 language sample. These variables are population size, longitude, latitude, relationship with the Central African rainforest, and border with Ubangi/Central Sudanic languages. All these measures are relevant, with population size and bordering with Ubangi/Central Sudanic being the most robust factors in accounting for the distribution of gender restructuring. We conclude that fine-tuned variable design tailored to language and area-specific ecologies is crucial to the advancement of quantitative sociolinguistic typology.

scholarly journals The role of matrilineality in shaping patterns of Y chromosome and mtDNA sequence variation in southwestern Angola

2018 ◽  
Author(s):  
Sandra Oliveira ◽  
Alexander Hübner ◽  
Anne-Maria Fehn ◽  
Teresa Aço ◽  
Fernanda Lages ◽  
...  
Keyword(s):  
Y Chromosome ◽  
Sequence Data ◽  
Population History ◽  
Female Population ◽  
Bantu Languages ◽  
Mtdna Sequence ◽  
Population Sizes ◽  
Group Variation ◽  
History Of ◽  
Previous Demonstration

AbstractSouthwestern Angola is a region characterized by contact between indigenous foragers and incoming food-producers, involving genetic and cultural exchanges between peoples speaking Kx’a, Khoe-Kwadi and Bantu languages. Although present-day Bantu-speakers share a patrilocal residence pattern and matrilineal principle of clan and group membership, a highly stratified social setting divides dominant pastoralists from marginalized groups that subsist on alternative strategies and have previously been though to have pre-Bantu origins. Here, we compare new high-resolution sequence data from 2.3 Mb of the non-recombining Y chromosome (NRY) from 170 individuals with previously reported mitochondrial genomes (mtDNA), to investigate the population history of seven representative southwestern Angolan groups (Himba, Kuvale, Kwisi, Kwepe, Twa, Tjimba, !Xun) and to study the causes and consequences of sex-biased processes in their genetic variation. We found no clear link between the formerly Kwadi-speaking Kwepe and pre-Bantu eastern African migrants, and no pre-Bantu NRY lineages among Bantu-speaking groups, except for small amounts of “Khoisan” introgression. We therefore propose that irrespective of their subsistence strategies, all Bantu-speaking groups of the area share a male Bantu origin. Additionally, we show that in Bantu-speaking groups, the levels of among-group and between-group variation are higher for mtDNA than for NRY. These results, together with our previous demonstration that the matriclanic systems of southwestern Angolan Bantu groups are genealogically consistent, suggest that matrilineality strongly enhances both female population sizes and interpopulation mtDNA variation.

scholarly journals An Efficient Algorithm for Estimating Population History from Genetic Data

2021 ◽  
Author(s):  
Alan R. Rogers
Keyword(s):  
Population Size ◽  
Efficient Algorithm ◽  
Genetic Data ◽  
Deterministic Algorithm ◽  
Population History ◽  
History Of

AbstractLegofit is a statistical package that uses genetic data to estimate the history of population size, subdivision, and admixture. This article describes a new deterministic algorithm, which makes Legofit orders of magnitude faster and more accurate.

scholarly journals Diversity and Paleodemography of the Addax (Addax nasomaculatus), a Saharan Antelope on the Verge of Extinction

Genes ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1236
Author(s):  
Elisabeth Hempel ◽  
Michael V. Westbury ◽  
José H. Grau ◽  
Alexandra Trinks ◽  
Johanna L. A. Paijmans ◽  
...  
Keyword(s):  
Population Size ◽  
Population History ◽  
Phylogeographic Structure ◽  
Recent Common Ancestor ◽  
Mitochondrial Genomes ◽  
Effective Population ◽  
Mammal Species ◽  
Human Disturbances ◽  
Most Recent Common Ancestor ◽  
History Of

Since the 19th century, the addax (Addax nasomaculatus) has lost approximately 99% of its former range. Along with its close relatives, the blue antelope (Hippotragus leucophaeus) and the scimitar-horned oryx (Oryx dammah), the addax may be the third large African mammal species to go extinct in the wild in recent times. Despite this, the evolutionary history of this critically endangered species remains virtually unknown. To gain insight into the population history of the addax, we used hybridization capture to generate ten complete mitochondrial genomes from historical samples and assembled a nuclear genome. We found that both mitochondrial and nuclear diversity are low compared to other African bovids. Analysis of mitochondrial genomes revealed a most recent common ancestor ~32 kya (95% CI 11–58 kya) and weak phylogeographic structure, indicating that the addax likely existed as a highly mobile, panmictic population across its Sahelo–Saharan range in the past. PSMC analysis revealed a continuous decline in effective population size since ~2 Ma, with short intermediate increases at ~500 and ~44 kya. Our results suggest that the addax went through a major bottleneck in the Late Pleistocene, remaining at low population size prior to the human disturbances of the last few centuries.

scholarly journals Introgression makes waves in inferred histories of effective population size

2017 ◽  
Author(s):  
John Hawks
Keyword(s):  
Gene Flow ◽  
Population Size ◽  
Effective Population Size ◽  
Population History ◽  
Human Populations ◽  
Effective Population ◽  
History Of ◽  
Or Gene ◽  
Time Of Origin ◽  
Past Population

AbstractHuman populations have a complex history of introgression and of changing population size. Human genetic variation has been affected by both these processes, so that inference of past population size depends upon the pattern of gene flow and introgression among past populations. One remarkable aspect of human population history as inferred from genetics is a consistent “wave” of larger effective population size, prior to the bottlenecks and expansions of the last 100,000 years. Here I carry out a series of simulations to investigate how introgression and gene flow from genetically divergent ancestral populations affect the inference of ancestral effective population size. Both introgression and gene flow from an extinct, genetically divergent population consistently produce a wave in the history of inferred effective population size. The time and amplitude of the wave reflect the time of origin of the genetically divergent ancestral populations and the strength of introgression or gene flow. These results demonstrate that even small fractions of introgression or gene flow from ancient populations may have large effects on the inference of effective population size.

Major Factors Associated with Congenital Malformations in the Agadir Region of Morocco

2020 ◽  
Vol 3 (8) ◽  
Author(s):  
SAID EL MADIDI
Keyword(s):  
Risk Factors ◽  
Congenital Malformations ◽  
International Classification Of Diseases ◽  
The Body ◽  
Explanatory Variables ◽  
Classification Of Diseases ◽  
History Of ◽  
Major Factors

Introduction: Congenital malformations are a global health problem around the world. MCs is one of the main causes of death and disability of newborns worldwide, but the majority of its risk factors are still poorly understood. Objective: The aim of this study is to determine the main causes that are related to the incidence of congenital malformations (CMs) in the region of Agadir in Morocco. Material and Methods: A prospective cases-control study at regional level was conducted in the pediatrics and neonatology department of Hassan II hospital in Agadir from April 2016 to April 2018. Data on child and maternal variables were recorded for 3701 newborns. The types of congenital malformations  have been classified according to the codes of the International Classification of Diseases. Univariate analyzes were performed to identify the variables associated with the etiology of the malformations. Multiple logistic regression was used to characterize the associations between the MC and the determining explanatory variables taken into account simultaneously. Results: The results of these studies showed that there is a significant association between the incidence of the Congenital anomalies and the level of the consanguinity of the child, the prematurity of childbirth, the family history of CMs, the body mass index of the mother and the presence of major trauma during pregnancy. Conclusion: our results have made it possible to highlight the existence of an association between a certain number of risk factors and the occurrence of congenital malformations. Additional studies are needed to confirm and clarify the role of these risk factors.

scholarly journals Inference of Historical Population-Size Changes with Allele-Frequency Data

2019 ◽  
Vol 10 (1) ◽  
pp. 211-223 ◽  
Author(s):  
Michael Lynch ◽  
Bernhard Haubold ◽  
Peter Pfaffelhuber ◽  
Takahiro Maruki
Keyword(s):  
Population Size ◽  
Probability Distributions ◽  
Daphnia Pulex ◽  
Population History ◽  
Effective Population ◽  
Size Change ◽  
Conceptual Approach ◽  
Population Genomic ◽  
Population Sizes ◽  
History Of

With up to millions of nearly neutral polymorphisms now being routinely sampled in population-genomic surveys, it is possible to estimate the site-frequency spectrum of such sites with high precision. Each frequency class reflects a mixture of potentially unique demographic histories, which can be revealed using theory for the probability distributions of the starting and ending points of branch segments over all possible coalescence trees. Such distributions are completely independent of past population history, which only influences the segment lengths, providing the basis for estimating average population sizes separating tree-wide coalescence events. The history of population-size change experienced by a sample of polymorphisms can then be dissected in a model-flexible fashion, and extension of this theory allows estimation of the mean and full distribution of long-term effective population sizes and ages of alleles of specific frequencies. Here, we outline the basic theory underlying the conceptual approach, develop and test an efficient statistical procedure for parameter estimation, and apply this to multiple population-genomic datasets for the microcrustacean Daphnia pulex.

scholarly journals Recent effective population size in Eastern European plain Russians correlates with the key historical events

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ural Yunusbaev ◽  
Arslan Ionusbaev ◽  
Giyoun Han ◽  
Hyung Wook Kwon
Keyword(s):  
Population Size ◽  
Ethnic Group ◽  
Effective Population Size ◽  
Ural Region ◽  
Population History ◽  
Eastern European ◽  
Effective Population ◽  
History Of ◽  
Key Events ◽  
Volga Ural Region

Abstract Effective population size reflects the history of population growth, contraction, and structuring. When the effect of structuring is negligible, the inferred trajectory of the effective population size can be informative about the key events in the history of a population. We used the IBDNe and DoRIS approaches, which exploit the data on IBD sharing between genomes, to reconstruct the recent effective population size in two population datasets of Russians from Eastern European plain: (1) ethnic Russians sampled from the westernmost part of Russia; (2) ethnic Russians, Bashkirs, and Tatars sampled from the Volga-Ural region. In this way, we examined changes in effective population size among ethnic Russians that reside in their historical area at the West of the plain, and that expanded eastward to come into contact with the indigenous peoples at the East of the plain. We compared the inferred demographic trajectories of each ethnic group to written historical data related to demographic events such as migration, war, colonization, famine, establishment, and collapse of empires. According to IBDNe estimations, 200 generations (~6000 years) ago, the effective size of the ancestral populations of Russians, Bashkirs, and Tatars hovered around 3,000, 30,000, and 8,000 respectively. Then, the ethnic Russians exponentially grew with increasing rates for the last 115 generations and become the largest ethnic group of the plain. Russians do not show any drop in effective population size after the key historical conflicts, including the Mongol invasion. The only exception is a moderate drop in the 17th century, which is well known in Russian history as The Smuta. Our analyses suggest a more eventful recent population history for the two small ethnic groups that came into contact with ethnic Russians in the Volga-Ural region. We found that the effective population size of Bashkirs and Tatars started to decrease during the time of the Mongol invasion. Interestingly, there is an even stronger drop in the effective population size that coincides with the expansion of Russians to the East. Thus, 15–20 generations ago, i.e. in the 16–18th centuries in the trajectories of Bashkirs and Tatars, we observe the bottlenecks of four and twenty thousand, respectively. Our results on the recent effective population size correlate with the key events in the history of populations of the Eastern European plain and have importance for designing biomedical studies in the region.

Runs of Homozygosity and Population History of Three Horse Breeds With Small Population Size

2018 ◽  
Vol 71 ◽  
pp. 27-34 ◽  
Author(s):  
Gertrud Grilz-Seger ◽  
Matjaz Mesarič ◽  
Marko Cotman ◽  
Markus Neuditschko ◽  
Thomas Druml ◽  
...  
Keyword(s):  
Population Size ◽  
Small Population ◽  
Population History ◽  
Runs Of Homozygosity ◽  
Small Population Size ◽  
History Of

The Population History of Britain and Ireland 1500-1750

1996 ◽  
Vol 50 (2) ◽  
pp. 284-285
Author(s):  
Eilidh Garrett
Keyword(s):  
Population History ◽  
History Of
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