scholarly journals Inferring the History of Population Size Change from Genome-Wide SNP Data

2012 ◽  
Vol 29 (12) ◽  
pp. 3653-3667 ◽  
Author(s):  
Christoph Theunert ◽  
Kun Tang ◽  
Michael Lachmann ◽  
Sile Hu ◽  
Mark Stoneking
2014 ◽  
Author(s):  
Olivier Mazet ◽  
Willy Rodríguez ◽  
Lounès Chikhi

The rapid development of sequencing technologies represents new opportunities for population genetics research. It is expected that genomic data will increase our ability to reconstruct the history of populations. While this increase in genetic information will likely help biologists and anthropologists to reconstruct the demographic history of populations, it also represents new challenges. Recent work has shown that structured populations generate signals of population size change. As a consequence it is often difficult to determine whether demographic events such as expansions or contractions (bottlenecks) inferred from genetic data are real or due to the fact that populations are structured in nature. Given that few inferential methods allow us to account for that structure, and that genomic data will necessarily increase the precision of parameter estimates, it is important to develop new approaches. In the present study we analyse two demographic models. The first is a model of instantaneous population size change whereas the second is the classical symmetric island model. We (i) re-derive the distribution of coalescence times under the two models for a sample of size two, (ii) use a maximum likelihood approach to estimate the parameters of these models (iii) validate this estimation procedure under a wide array of parameter combinations, (iv) implement and validate a model choice procedure by using a Kolmogorov-Smirnov test. Altogether we show that it is possible to estimate parameters under several models and perform efficient model choice using genetic data from a single diploid individual.


2018 ◽  
Vol 47 (1) ◽  
pp. 65-72
Author(s):  
Luiza Ossowska ◽  
Natalia Bartkowiak-Bakun

The aim of this study is to discuss changes in thepopulation and indicate the main reasons of these changes inrural areas of West Pomeranian voivodeship. The study wasconducted on the local level and based on Central StatisticalOffice data from the years 2010 to 2014. In the first part ofthe research, main demographic information is discussed. Itincludes population density, natural increase per 1000 populationand net migration per 1000 population in rural areasof West Pomeranian voivodeship. In the next part of the research,the average population growth rate was counted in theyears 2011–2014. Based on these changes, researched unitswere divided into four groups – two groups with positivechanges and two groups with negative changes. Subsequently,the main reasons of the changes in population size were analyzedin particular groups including natural increase, migration,population structure by age, level of unemployment andentrepreneurship. All indicators were designated as averagesfrom 2011 to 2014. According to the results in most of the researchunits, the net migration determined the population size.The net migration was characterized by higher absolute valuesthan natural increase. The population size changes are relatedto density. The lowest density areas are more depopulated.Moreover, the population size changes are positive related tothe level of entrepreneurship and negative related to the levelof unemployment.


Author(s):  
Haige Han ◽  
Kenneth Bryan ◽  
Wunierfu Shiraigol ◽  
Dongyi Bai ◽  
Yiping Zhao ◽  
...  

Abstract The Mongolian horse is one of the oldest extant horse populations and although domesticated, most animals are free-ranging and experience minimal human intervention. As an ancient population originating in one of the key domestication centers, the Mongolian horse may play a key role in understanding the origins and recent evolutionary history of horses. Here we describe an analysis of high-density genome-wide single-nucleotide polymorphism (SNP) data in 40 globally dispersed horse populations (n = 895). In particular, we have focused on new results from Chinese Mongolian horses (n = 100) that represent 5 distinct populations. These animals were genotyped for 670K SNPs and the data were analyzed in conjunction with 35K SNP data for 35 distinct breeds. Analyses of these integrated SNP data sets demonstrated that the Chinese Mongolian populations were genetically distinct from other modern horse populations. In addition, compared to other domestic horse breeds, the Chinese Mongolian horse populations exhibited relatively high genomic diversity. These results suggest that, in genetic terms, extant Chinese Mongolian horses may be the most similar modern populations to the animals originally domesticated in this region of Asia. Chinese Mongolian horse populations may therefore retain ancestral genetic variants from the earliest domesticates. Further genomic characterization of these populations in conjunction with archaeogenetic sequence data should be prioritized for understanding recent horse evolution and the domestication process that has led to the wealth of diversity observed in modern global horse breeds.


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