Migration and genetic diversity in an island population: Karkar, Papua New Guinea

1978 ◽  
Vol 202 (1147) ◽  
pp. 269-295 ◽  
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Age Groups ◽  
New Guinea ◽  
Genetic Distances ◽  
Human Populations ◽  
Island Population ◽  
Evolutionary Forces ◽  
Married Individuals ◽  
Linguistic Groups

This paper examines genetic diversity on Karkar Island, Papna New Guinea, and its relation to patterns of migration within and between the two linguistic groups (Waskia and Takia) on the island. Exchange between linguistic groups is found to be small: less than 3 % of married individuals living in one linguistic group were born in the other. There is evidence of a secular trend in movement with significantly greater proportions of younger married individuals living outside their village group of birth. The migration patterns are examined by principal coordinate analysis of kinship coefficients derived from three sets of migration probabilities: ages 15—29, 30—44, 45 and over. For all three age groups the linguistic division is preserved and there is broad agreement between relatedness and the geographical arrangement of the village groups. The 22 polymorphic genetic systems examined show considerable diversity, most of which is within or between village groups in the same linguistic division. The greater level of diversity between Takia groups is consistent with their greater isolation from one another. Genetic distances between village groups show good agreement with geographical distances and there is no overlap between Waskia and Takia. The present-day genetic structure of Karkar Island can be interpreted as being largely the result of the interplay of migration and drift processes. The paper considers the use of analyses of this kind in establishing the magnitude and role of evolutionary forces operating on the genetic structure of human populations and the problems of unravelling rigorously and in detail the historical development of this structure.

scholarly journals Genomic and demographic processes differentially influence genetic variation across the X chromosome

2021 ◽  
Author(s):  
Daniel J. Cotter ◽  
Timothy H. Webster ◽  
Melissa A. Wilson
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Linkage Disequilibrium ◽  
X Chromosome ◽  
Global Scale ◽  
Careful Consideration ◽  
Human Populations ◽  
Evolutionary Forces ◽  
Ideal System ◽  
Demographic Patterns

AbstractMutation, recombination, selection, and demography affect genetic variation across the genome. Increased mutation and recombination both lead to increases in genetic diversity in a region-specific manner, while complex demographic patterns shape patterns of diversity on a more global scale. The X chromosome is particularly interesting because it contains several distinct regions that are subject to different combinations and strengths of these processes, notably the pseudoautosomal regions (PARs) and the X-transposed region (XTR). The X chromosome thus can serve as a unique model for studying how genetic and demographic forces act in different contexts to shape patterns of observed variation. Here we investigate diversity, divergence, and linkage disequilibrium in each region of the X chromosome using genomic data from 26 human populations. We find that both diversity and substitution rate are consistently elevated in PAR1 and the XTR compared to the rest of the X chromosome. In contrast, linkage disequilibrium is lowest in PAR1 and highest on the non-recombining X chromosome, with the XTR falling in between, suggesting that the XTR (usually included in the non-recombining X) may need to be considered separately in future studies. We also observed strong population-specific effects on genetic diversity; not only does genetic variation differ on the X and autosomes among populations, but the effects of linked selection on the X relative to autosomes have been shaped by population-specific history. The substantial variation in patterns of variation across these regions provides insight into the unique evolutionary history contained within the X chromosome.Significance StatementDemography and selection affect the X chromosome differently from non-sex chromosomes. However, the X chromosome can be subdivided into multiple distinct regions that facilitate even more fine-scaled assessment of these processes. Here we study regions of the human X chromosome in 26 populations to find evidence that recombination may be mutagenic in humans and that the X-transposed region may undergo recombination. Further we observe that the effects of selection and demography act differently on the X chromosome relative to the autosomes across human populations. Together, our results highlight profound regional differences across the X chromosome, simultaneously making it an ideal system for exploring the action of evolutionary forces as well as necessitating its careful consideration and treatment in genomic analyses.

scholarly journals Spectrum of genetic diversity and networks of clonal organisms

2007 ◽  
Vol 4 (17) ◽  
pp. 1093-1102 ◽  
Author(s):  
Alejandro F Rozenfeld ◽  
Sophie Arnaud-Haond ◽  
Emilio Hernández-García ◽  
Víctor M Eguíluz ◽  
Manuel A Matías ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Genetics ◽  
Genetic Structure ◽  
Small World ◽  
Clonal Plants ◽  
Posidonia Oceanica ◽  
Genetic Distances ◽  
Wide Range ◽  
Clonal Organisms ◽  
Genetic Structure And Diversity

Clonal reproduction characterizes a wide range of species including clonal plants in terrestrial and aquatic ecosystems, and clonal microbes such as bacteria and parasitic protozoa, with a key role in human health and ecosystem processes. Clonal organisms present a particular challenge in population genetics because, in addition to the possible existence of replicates of the same genotype in a given sample, some of the hypotheses and concepts underlying classical population genetics models are irreconcilable with clonality. The genetic structure and diversity of clonal populations were examined using a combination of new tools to analyse microsatellite data in the marine angiosperm Posidonia oceanica . These tools were based on examination of the frequency distribution of the genetic distance among ramets, termed the spectrum of genetic diversity (GDS), and of networks built on the basis of pairwise genetic distances among genets. Clonal growth and outcrossing are apparently dominant processes, whereas selfing and somatic mutations appear to be marginal, and the contribution of immigration seems to play a small role in adding genetic diversity to populations. The properties and topology of networks based on genetic distances showed a ‘small-world’ topology, characterized by a high degree of connectivity among nodes, and a substantial amount of substructure, revealing organization in subfamilies of closely related individuals. The combination of GDS and network tools proposed here helped in dissecting the influence of various evolutionary processes in shaping the intra-population genetic structure of the clonal organism investigated; these therefore represent promising analytical tools in population genetics.

Genetic structure analysis of domestic duck populations in eastern China

2008 ◽  
Vol 5 (3) ◽  
pp. 183-187
Author(s):  
Li Hui-Fang ◽  
Song Wei-Tao ◽  
Zhu Wen-Qi ◽  
Xu Wen-Juan ◽  
Tang Qing-Ping
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Genetic Structure ◽  
Eastern China ◽  
Genetic Distances ◽  
Domestic Duck ◽  
Average Heterozygosity ◽  
Rich Diversity ◽  
Breed Differences ◽  
The Rich

AbstractUsing microsatellite markers, the genetic structure of nine domestic duck (Anas platyrhynchos) populations in eastern China was analysed. The results showed that the heterozygosity was high in these populations, ranging from 0.5137 to 0.6055, with an average heterozygosity of 0.5523, reflecting the rich diversity. Considerable breed differentiation was observed and 25.65% of the total genetic variation came from breed differences; this low differentiation result affirmed that each breed has its own genetic diversity. The DA genetic distances suggested that greater differentiation existed between populations. The duck populations were clustered into four groups based on neighbour joining (NJ) clustering, and the clustering results showed relationships with duck breed distributions and economic utilization.

Landscape genetic structure of Pinus banksiana: allozyme variation

2001 ◽  
Vol 79 (8) ◽  
pp. 871-878 ◽  
Author(s):  
Cuauhtemoc Saenz-Romero ◽  
Raymond P Guries ◽  
Andrew I Monk
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Structure ◽  
Pinus Banksiana ◽  
Allozyme Variation ◽  
Jack Pine ◽  
Genetic Distances ◽  
Jack Pine Forests ◽  
Forest Mosaic ◽  
Landscape Genetic

Many of Wisconsin's jack pine forests originated following fire or agricultural abandonment creating a forest mosaic fragmented by a history of disturbance and past land use. The extent and patterning of genetic diversity at a landscape scale (30 × 30 km) was investigated in 82 natural Pinus banksiana Lamb. (jack pine) stands in Wisconsin using 14 polymorphic allozymes. Most measures of genetic diversity and overall allelic frequencies varied little among these stands, and Reynolds' (coancestry) genetic distances were small (mean = 0.026). Genetic differentiation among stands was limited but significant ([Formula: see text]ST = 0.022). Gene flow (Nm) is extensive, estimated to be slightly more than 11 migrants per generation. Autocorrelation analysis provided evidence for a weak pattern of genetic structure at a few loci with a spatial scale of 8–15 km. However, when all loci were examined together the populations did not present a clear spatial pattern across the landscape, probably because of extensive gene flow among stands.Key words: jack pine, allozymes, genetic diversity, population differentiation, spatial autocorrelation, gene flow.

A new species of Cyrtodactylus Gray (Gekkonidae: Squamata) from Manus Island, and extended description and range extension for Cyrtodactylus sermowaiensis (De Rooij)

Zootaxa ◽  
2020 ◽  
Vol 4728 (3) ◽  
pp. 341-356
Author(s):  
PAUL M. OLIVER ◽  
RYAN HARTMAN ◽  
CAMERON D. TURNER ◽  
TAYLOR A. WILDE ◽  
CHRISTOPHER C. AUSTIN ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
New Species ◽  
Genetic Structure ◽  
Morphological Variation ◽  
Morphological Differentiation ◽  
Sedimentary Basins ◽  
New Guinea ◽  
Isolated Population ◽  
The North ◽  
A New Species

Systematic investigations of vertebrate faunas from the islands of Melanesia are revealing high levels of endemism, dynamic biogeographic histories, and in some cases surprisingly long evolutionary histories of insularity. The bent-toed geckos in the Cyrtodactylus sermowaiensis Group mainly occur in northern New Guinea and nearby islands, however a further isolated population occurs on Manus Island in the Admiralty Archipelago approximately 300 km to the north of New Guinea. Here we first present a review of the genetic diversity, morphological variation and distribution of Cyrtodactylus sermowaiensis from northern New Guinea. Genetic structure and distributional records within Cyrtodactylus sermowaiensis broadly overlap with underlying Terranes in northern New Guinea, suggesting divergence on former islands that have been obscured by the infill and uplift of sedimentary basins since the late Pleistocene. Based on a combination of genetic and morphological differentiation we then describe the population from Manus Island as a new species, Cyrtodactylus crustulus sp. nov. This new species emphasises the high biological endemism and conservation significance of the Admiralty Islands, and especially Manus Island. 

scholarly journals Genetic Structure and Variability of Natural Populations of Maritime Pine (Pinus pinaster Aiton) in Morocco

2004 ◽  
Vol 53 (1-6) ◽  
pp. 93-99 ◽  
Author(s):  
N. Wahid ◽  
S. C. González-Martínez ◽  
I. El Hadrami ◽  
A. Boulli
Keyword(s):  
Genetic Diversity ◽  
Molecular Markers ◽  
Genetic Structure ◽  
Gene Diversity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Natural Populations ◽  
Genetic Distances ◽  
Maritime Pine ◽  
High Atlas ◽  
Middle Atlas

Abstract The estimation of genetic diversity using molecular markers is a major component of genetic conservation programs. In its range, Maritime pine has been extensively studied using different molecular markers and quantitative traits. However, Moroccan populations have been usually represented only by a few typical locations in the Middle Atlas (e.g., Tamjout). To describe the genetic structure and variability of maritime pine in Morocco, eleven populations of this species comprising all major geographic regions (Rif, Middle Atlas and High Atlas) were studied using allozyme markers. A total of 471 samples were analyzed using polyacrylamide gel electrophoresis (PAGE) of eight enzyme systems encoded by 19 loci. Genetic variation was lower in Morocco than in other ranges of the species. However, genetic diversity was structured and a high differentiation among populations (θ = 10.44%) and a moderate correlation between genetic and geographic distances were found (0.350). Three main groups of populations can be distinguished based on genetic distances: (i) Mediterranean Coastal, (ii) Occidental Rif and Middle Atlas and (iii) High Atlas. The populations from Middle Atlas presented the lowest values of allelic richness and gene diversity whereas the populations from Rif showed a considerable amount of genetic variability. Human impact and isolation are major factors explaining population genetic structure of maritime pine in Morocco. Overexploitation of the forest by intensive cattle grazing and land speculation are suggested to be active mechanisms currently deploying the genetic resources of this species.

scholarly journals Analysis of the mitochondrial CYTB gene sequence in human populations of northeastern Bosnia

2019 ◽  
Vol 82 (3) ◽  
pp. 221-238
Author(s):  
Adisa Ahmic ◽  
Irma Mujkic ◽  
Anel Ismailovic ◽  
Emir Halilovic ◽  
Lejla Lasic ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Human Populations ◽  
Roma Population ◽  
Additional Information ◽  
Mitochondrial Cytochrome B ◽  
Different Populations ◽  
Two Populations ◽  
Maternal Gene

Abstract This study offers the first report on variation sequence of the mitochondrial cytochrome b (MT-CYTB) gene in populations from Bosnia (northeastern Bosnia). This study was designed on the analysis of the genetic diversity of two populations of different cultural-anthropological and genetic origin, Roma population and native/non-Roma population. The main aim of our study was to estimate the usefulness of the CYTB sequence in the analysis of genetic categorization of different populations and intergroup diversity, as well as to provide some additional information on haplogroup-associated polymorphisms within the CYTB region in defining haplogroup status. Estimation of the genetic diversity was done using intra and intergroup genetic indices. The population-specific polymorphisms have been found in both categories of the populations. The results of the analysis of genetic differentiation show significant pairwise Fst differences between the Romani and native populations. Also, registered significant genetic differentiation is illustrated on the level of genetic variation between subpopulations of the Roma and non-Roma origin. The important result in our study is the confirmation of the significance of the triad of polymorphisms T14783C-G15043A-G15301A, indicating the influence of Asian component of the maternal gene pool on the genetic structure of the studied population of the Roma. Our data show that the haplogroup polymorphisms exist in the CYTB region and can provide useful information on the haplogroups that were defined only by the control region of the mtDNA. The results of this study indicate the region of CYTB gene can be a benefit in providing some additional information in the analysis of genetic structure of human populations and can be additionally applied in population studies.

scholarly journals Genetic diversity in global chicken breeds as a function of genetic distance to the wild populations

2020 ◽  
Author(s):  
Dorcus Kholofelo Malomane ◽  
Steffen Weigend ◽  
Armin Otto Schmitt ◽  
Annett Weigend ◽  
Christian Reimer ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Differentiation ◽  
Genetic Distance ◽  
Isolation By Distance ◽  
Genetic Distances ◽  
Founder Population ◽  
Wild Populations ◽  
Metabolic Processes ◽  
Evolutionary Forces ◽  
The Relationship

AbstractMigration of populations from their founder population is expected to cause a reduction in genetic diversity and facilitates population differentiation between the populations and their founder population as predicted by the theory of genetic isolation by distance. Consistent with that, a model of expansion from a single founder predicts that patterns of genetic diversity in populations can be well explained by their geographic expansion from the founders, which is correlated to the genetic differentiation. To investigate this in the chicken, we have estimated the relationship between the genetic diversity in 172 domesticated chicken populations and their genetic distances to wild populations. We have found a strong inverse relationship whereby 87.5% of the variation in the overall genetic diversity of domesticated chicken can be explained by the genetic distance to the wild populations. We also investigated if different types of SNPs and genes present similar patterns of genetic diversity as the overall genome. Among different SNP classes, the non-synonymous ones were the most deviating from the overall genome. However, the genetic distances to wild populations still explained more variation in domesticated chicken diversity in all SNP classes ranging from 81.7 to 88.7%. The genetic diversity seemed to change at a faster rate within the chicken in genes that are associated with transmembrane transport, protein transport and protein metabolic processes, and lipid metabolic processes. In general, such genes are flexible to be manipulated according to the population needs. On the other hand, genes which the genetic diversity hardly changes despite the genetic distance to the wild populations are associated with major functions e.g. brain development. Therefore, changes in the genes may be detrimental to the chickens. These results contribute to the knowledge of different evolutionary patterns of different functional genomic regions in the chicken.Author summaryThe chicken was first domesticated about 6000 B.C. in Asia from the jungle fowl. Following domestication, chickens were taken to different parts of the world mainly by humans. Evolutionary forces such as selection and genetic drift have shaped diversification within the chicken species. In addition, new breeds or strains have been developed from crossbreeding programs facilitated by man. These events, together with other breeding practices, have led to genomic alterations causing genetic differentiation between the domesticated chickens and their ancestral/wild population as well as manipulation of the genetic diversity within the domesticated chickens. We investigated the relationship between 172 domesticated chicken populations from different selection, breeding and management backgrounds and their genetic distance to the wild type chickens. We found that the genetic diversity within the populations decreases with the increasing genetic distances to the wild types. Human manipulation of chicken genetic diversity has more effect on the genetic differentiation than simple geographic separations (through migrations) do. We further found that some genes associated with vital functions show evolutionary constraints or persistent selection across the populations and do not comply with this relationship i.e. the genetic diversity within the populations is constant despite the change in the genetic distance to the wild types.

scholarly journals Evolutionary Dynamics of Oropouche Virus in South America

2019 ◽  
Vol 94 (5) ◽  
Author(s):  
Bernardo Gutierrez ◽  
Emma L. Wise ◽  
Steven T. Pullan ◽  
Christopher H. Logue ◽  
Thomas A. Bowden ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
South America ◽  
Amazon Basin ◽  
Evolutionary Dynamics ◽  
Yellow Fever Virus ◽  
Surface Proteins ◽  
Human Populations ◽  
Evolutionary Processes ◽  
Public Health Burden ◽  
Evolutionary Forces

ABSTRACT The Amazon basin is home to numerous arthropod-borne viral pathogens that cause febrile disease in humans. Among these, Oropouche orthobunyavirus (OROV) is a relatively understudied member of the genus Orthobunyavirus, family Peribunyaviridae, that causes periodic outbreaks in human populations in Brazil and other South American countries. Although several studies have described the genetic diversity of the virus, the evolutionary processes that shape the OROV genome remain poorly understood. Here, we present a comprehensive study of the genomic dynamics of OROV that encompasses phylogenetic analysis, evolutionary rate estimates, inference of natural selective pressures, recombination and reassortment, and structural analysis of OROV variants. Our study includes all available published sequences, as well as a set of new OROV genome sequences obtained from patients in Ecuador, representing the first set of genomes from this country. Our results show differing evolutionary processes on the three segments that comprise the viral genome. We infer differing times of the most recent common ancestors of the genome segments and propose that this can be explained by cryptic reassortment. We also present the discovery of previously unobserved putative N-linked glycosylation sites, as well as codons that evolve under positive selection on the viral surface proteins, and discuss the potential role of these features in the evolution of OROV through a combined phylogenetic and structural approach. IMPORTANCE The emergence and reemergence of pathogens such as Zika virus, chikungunya virus, and yellow fever virus have drawn attention toward other cocirculating arboviruses in South America. Oropouche virus (OROV) is a poorly studied pathogen responsible for over a dozen outbreaks since the early 1960s and represents a public health burden to countries such as Brazil, Panama, and Peru. OROV is likely underreported since its symptomatology can be easily confounded with other febrile illnesses (e.g., dengue fever and leptospirosis) and point-of-care testing for the virus is still uncommon. With limited data, there is a need to optimize the information currently available. Analysis of OROV genomes can help us understand how the virus circulates in nature and can reveal the evolutionary forces that shape the genetic diversity of the virus, which has implications for molecular diagnostics and the design of potential vaccines.

scholarly journals Divergence among maize genotypes with different kernel types according to SSR marker analysis

Genetika ◽  
2019 ◽  
Vol 51 (1) ◽  
pp. 237-249
Author(s):  
Ana Nikolic ◽  
Natalija Kravic ◽  
Jelena Srdic ◽  
Dragan Kovacevic ◽  
Violeta Andjelkovic ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Gene Diversity ◽  
Distance Matrix ◽  
Genetic Distances ◽  
Model Based Clustering ◽  
Cluster Data ◽  
Upgma Cluster Analysis ◽  
Yellow Orange ◽  
Kernel Type

Panels of diverse materials have proven to be very useful in evaluation of the organization of genetic diversity available for breeding at phenotypic and genotypic levels. In this study, a panel consisting of several groups of maize inbreds was tested using microstelite markers. The aim of this study was to test genetic diversity and define population structure of twenty-four genotypes differing in kernel type (dent, flint, popcorn, sweet maize) and kernel color (white, yellow, orange) with 21 SSRs. Genetic diversity parameters such as number of alleles, gene diversity, observed heterozygosity, PIC (Polymorphism Information Content) and number of unique alleles were determined. In addition, genetic distances according to Rogers distance were calculated. The values for all parameters were high, reflecting high genetic divergence of analyzed germplasm. Distance matrix based on UPGMA cluster analysis showed moderate congruence to available pedigree/origin or kernel type/color data. Genetic structure of tested genotypes was defined using Bayesian model-based clustering, without a considerable difference in comparison to cluster data analysis. The determined diversity parameters along with the results concerning genetic structure analysis provided a valuable information for improved selection efficiency.

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