The founding of New World populations by Asian peoples is the focus of considerable archaeological and genetic research, and there persist important questions on when and how these events occurred. Genetic data offer great potential for the study of human population history, but there are significant challenges in discerning distinct demographic processes. A new method for the study of diverging populations was applied to questions on the founding and history of Amerind-speaking Native American populations. The model permits estimation of founding population sizes, changes in population size, time of population formation, and gene flow. Analyses of data from nine loci are consistent with the general portrait that has emerged from archaeological and other kinds of evidence. The estimated effective size of the founding population for the New World is fewer than 80 individuals, approximately 1% of the effective size of the estimated ancestral Asian population. By adding a splitting parameter to population divergence models it becomes possible to develop detailed portraits of human demographic history. Analyses of Asian and New World data support a model of a recent founding of the New World by a population of quite small effective size.

Island populations are on average smaller, genetically less diverse, and at a higher risk to go extinct than mainland populations. Low genetic diversity may elevate extinction probability, but the genetic component of the risk can be affected by the mode of diversity loss, which, in turn, is connected to the demographic history of the population. Here, we examined the history of genetic erosion in three Fennoscandian ringed seal subspecies, of which one inhabits the Baltic Sea ‘mainland’ and two the ‘aquatic islands’ composed of Lake Saimaa in Finland and Lake Ladoga in Russia. Both lakes were colonized by marine seals after their formation c. 9500 years ago, but Lake Ladoga is larger and more contiguous than Lake Saimaa. All three populations suffered dramatic declines during the 20th century, but the bottleneck was particularly severe in Lake Saimaa. Data from 17 microsatellite loci and mitochondrial control-region sequences show that Saimaa ringed seals have lost most of the genetic diversity present in their Baltic ancestors, while the Ladoga population has experienced only minor reductions. Using Approximate Bayesian computing analyses, we show that the genetic uniformity of the Saimaa subspecies derives from an extended founder event and subsequent slow erosion, rather than from the recent bottleneck. This suggests that the population has persisted for nearly 10,000 years despite having low genetic variation. The relatively high diversity of the Ladoga population appears to result from a high number of initial colonizers and a high post-colonization population size, but possibly also by a shorter isolation period and/or occasional gene flow from the Baltic Sea.

Historical Foundings of Cities by Century. Map type: Symbols. Spatial extent: Switzerland plus. Times: before 1000, 1000 - 1100, 1100 - 1200, 1200 - 1300, 1300 -1400, 1400 -1500, Overall period

The introduction of non-native species can have long-term effects on native plant and animal communities. Introduced populations are occasionally not well understood and offer opportunities to evaluate changes in genetic structure through time and major population changes such as bottleneck and or founder events. Invasive species can often evolve rapidly in new and novel environments, which could be essential to their long-term success. Sika deer are native to East Asia, and their introduction and establishment to the Delmarva Peninsula, USA is poorly documented, but probably involved ≥1 founder and/or bottleneck events. We quantified neutral genetic diversity in the introduced population and compared genetic differentiation and diversity to the presumed source population from Yakushima Island, Japan, and a captive population of sika deer in Harrington, Delaware, USA. Based on data from 10 microsatellite DNA loci, we observed reduced genetic variation attributable to founder events, support for historic hybridization events, and evidence that the population did originate from Yakushima Island stocks. Estimates of population structure through Bayesian clustering and demographic history derived from Approximate Bayesian Computation (ABC), were consistent with the hypothesized founder history of the introduced population in both timing and effective population size (approximately 5 effective breeding individuals, an estimated 36 generations ago). Our ABC results further supported a single introduction into the wild happening before sika deer spread throughout the Delmarva. We conclude that free-ranging sika deer on Delmarva are descended from ca. 5 individuals introduced about 100 years ago from captive stocks of deer maintained in the United Kingdom. Free-ranging sika deer on Delmarva have lost neutral diversity due to founder and bottleneck events, yet populations have expanded in recent decades and show no evidence of abnormalities associated with inbreeding. We suggest management practices including increasing harvest areas and specifically managing sika deer outside of Maryland.

For years, studies of founder populations and genetic isolates represented the mainstream of genetic mapping in the effort to target genetic defects causing Mendelian disorders. The genetic homogeneity of such populations as well as relatively homogeneous environmental exposures were also seen as primary advantages in studies of genetic susceptibility loci that underlie complex diseases. European colonization of the St-Lawrence Valley by a small number of settlers, mainly from France, resulted in a founder effect reflected by the appearance of a number of population-specific disease-causing mutations in Quebec. The purported genetic homogeneity of this population was recently challenged by genealogical and genetic analyses. We studied one of the contributing factors to genetic heterogeneity, early Native American admixture that was never investigated in this population before. Consistent admixture estimates, in the order of one per cent, were obtained from genome-wide autosomal data using the ADMIXTURE and HAPMIX software, as well as with the fastIBD software evaluating the degree of the identity-by-descent between Quebec individuals and Native American populations. These genomic results correlated well with the genealogical estimates. Correlations are imperfect most likely because of incomplete records of Native founders’ origin in genealogical data. Although the overall degree of admixture is modest, it contributed to the enrichment of the population diversity and to its demographic stratification. Because admixture greatly varies among regions of Quebec and among individuals, it could have significantly affected the homogeneity of the population, which is of importance in mapping studies, especially when rare genetic susceptibility variants are in play.

Biological invasions provide excellent study systems to understand evolutionary, genetic and ecological processes during range expansions. There is strong evidence for positive effects of high propagule pressure and the associated higher genetic diversity on invasion success, but some species have become invasive despite small founder numbers. The raccoon (Procyon lotor) is often considered as a typical example for such a successful invasion resulting from a small number of founders. The species’ largest non-native population in Germany is commonly assumed to stem from a small number of founders and two separate founding events in the 1930s and 1940s. In the present study we analyzed 407 raccoons at 20 microsatellite loci sampled from the invasive range in Western Europe to test if these assumptions are correct. Contrary to the expectations, different genetic clustering methods detected evidence for at least four independent introduction events that gave rise to genetically differentiat...

Invasive species are widely recognized as important drivers of the ongoing biodiversity crisis. The US state of Florida is especially susceptible to the proliferation of invasive reptiles, and nonnative lizards currently outnumber native lizard species. At present, there are three documented breeding populations of the Nile monitor (Varanus niloticus) in different regions of Southern Florida, and these populations are considered potential dangers to threatened, fossorial endemics, such as burrowing owls, American crocodiles, and gopher tortoises. Nevertheless, at present, both the introduction histories of these populations and the degree to which they are connected by gene flow are not known. To address these issues, we genotyped V. niloticus from Cape Coral, Homestead Air Reserve Base, and West Palm Beach at 17 microsatellite loci and conducted a variety of analyses to assess both intra-population genetic diversity, the degree of gene flow between populations, and the most likely introduction scenario. The results of our analyses demonstrate that all three populations have limited genetic diversity (mean number of effective alleles across loci in all three populations ~ 2.00) and are highly differentiated from one another (GST = 0.268; G''ST = 0.628). Our results also suggest that these populations resulted from independent introduction events that occurred within the past few decades. Consequently, we advise that wildlife managers focus management efforts on containment of existing populations and intensification of monitoring efforts on potential migration corridors.

The world's Jewish population has had a complex and tumultuous history over the past millennia, regularly dealing with persecution, pogroms, and even genocide. The legacy of expulsion and persecution of Jews, including bans on land ownership, meant that Jewish communities disproportionately lived in urban areas, working as artisans or traders, and often lived in their own settlements separate to the rest of the urban population. This separation contributed to the impression that events such as pandemics, famines, or economic shocks did not affect Jews as much as other populations, and such factors came to form the basis of the mistrust and stereotypes of wealth (characterized as greed) that have made up anti-Semitic rhetoric for centuries. Development since the Middle Ages The concentration of Jewish populations across the world has shifted across different centuries. In the Middle Ages, the largest Jewish populations were found in Palestine and the wider Levant region, with other sizeable populations in present-day France, Italy, and Spain. Later, however, the Jewish disapora became increasingly concentrated in Eastern Europe after waves of pogroms in the west saw Jewish communities move eastward. Poland in particular was often considered a refuge for Jews from the late-Middle Ages until the 18th century, when it was then partitioned between Austria, Prussia, and Russia, and persecution increased. Push factors such as major pogroms in the Russian Empire in the 19th century and growing oppression in the west during the interwar period then saw many Jews migrate to the United States in search of opportunity.

Population introductions and reintroductions have become a common tool for conserving threatened species, but oftentimes introduced populations have reduced the genetic diversity compared with the source population they were founded from. Population introductions played an important role in the recovery of the Oregon Chub Oregonichthys crameri, a small floodplain minnow found in western Oregon. Unlike many introduction efforts, introduced populations of Oregon Chub were founded using large numbers of individuals (hundreds in many cases) and each population had a unique introduction history (e.g., number of founders, source populations selected, duration of the introduction effort). We used microsatellite loci to examine 13 introduced populations and their respective sources to evaluate how well the introduction program captured genetic diversity present in the wild populations. Genetic variation was reduced by roughly 25% in one introduced population, and three introduced populations showed evidence of a genetic bottleneck due to heterozygote excess. Populations introduced from multiple sources had greater genetic diversity than populations from a single source. When multiple source populations were used, all source populations contributed genetic material to the introduced population, though the proportional contribution from each source population varied. Using correlation analyses and general linear models, we explored the relationship between introduction history variables and genetic diversity. Our top-ranked models included genetic diversity in the source population, and this variable had the highest variable importance weight (0.999), but the number of founders and the number of source populations were also important. Overall, the Oregon Chub introduction program was highly successful at capturing the genetic variation observed in natural populations. Results of this study will be useful for planning future population introductions for Oregon Chub and other species of conservation concern.

Numbers of distinct and novel (newly introduced, i.e., in addition to those already present and introduced earlier), uniparentally inherited lineages (separately maternal and paternal) are reported as well. Contributing immigrants are those who transmitted their descendant lineages in the 1931–60 population.

Most founding events entail a reduction of population size, which in turn leads to genetic drift effects that can deplete alleles. Besides reducing neutral genetic variability, founder effects can in principle shift additive genetic variance for phenotypes that underlie fitness. This could then lead to different rates of adaptation among populations that have undergone a population size bottleneck as well as an environmental change, even when these populations have a common evolutionary history. Thus theory suggests that there should be an association between observable genetic variability for both neutral markers and phenotypes related to fitness. Here we test this scenario by monitoring the early evolutionary dynamics of six laboratory foundations derived from founders taken from the same source natural population of Drosophila subobscura. Each foundation was in turn three-fold replicated. During their first few generations, these six foundations showed an abrupt increase in their gen...

Most invasive species established in Europe originate from either Asia or North America, but little is currently known about the potential of the Anatolian Peninsula (Asia Minor) and/or the Near East to constitute invasion sources. Mediterranean forests are generally fragile ecosystems that can be threatened by invasive organisms coming from different regions of the Mediterranean Basin, but for which historical data are difficult to gather and the phylogeographic patterns are still poorly understood for most terrestrial organisms. In this study, we characterized the genetic structure of Megastigmus schimitscheki, an invasive seed-feeding insect species originating from the Near East, and elucidated its invasion route in Southeastern France in the mid 1990’s. To disentangle the evolutionary history of this introduction, we gathered samples from the main native regions (Taurus Mountains in Turkey, Lebanon and Cyprus) and from the invaded region, that we genotyped using five microsatellite...

Background: Intraspecific genetic variation of African fauna has been signific antly affected by pronounced climatic fluctuations in Plio-Pleistocene, but, with the exception of large mammals, very limited empirical data on diversity of natural populations are available for savanna-dwelling animals. Nothobranchius furzeri is an annual fish from south-eastern Africa, inhabiting discrete temporary savannah pools outside main river alluvia. Their dispersal is limited and population processes affecting its genetic structure are likely a combination of those affecting terrestrial and aquatic taxa. N. furzeri is a model taxon in ageing research and several populations of known geographical origin are used in laboratory studies. Here, we analysed the genetic structure, diversity, historical demography and temporal patterns of divergence in natural populations of N. furzeri across its entire distribution range. Results: Genetic structure and historical demography of N. furzeri were analysed us...

Genomic variation of an invasive species may be affected by complex demographic histories and evolutionary changes during invasions. Here, we describe the relative influence of bottlenecks, clonality, and population expansion in determining genomic variability of the widespread red macroalga Agarophyton vermiculophyllum. Its introduction from mainland Japan to the estuaries of North America and Europe coincided with shifts from predominantly sexual to partially clonal reproduction and rapid adaptive evolution. A survey of 62,285 SNPs for 351 individuals from 35 populations, aligned to 24 chromosome-length scaffolds indicate that linkage disequilibrium (LD), observed heterozygosity (H_o), Tajima's D, and nucleotide diversity (Pi) were greater among non-native than native populations. Evolutionary simulations indicate LD and Tajima's D were consistent with a severe population bottleneck. Also, the increased rate of clonal reproduction in the non-native range could not have produced the observed patterns by itself but may have magnified the bottleneck effect on LD. A bottleneck or clonality limitedly impact H_o and Pi, rather, the increased H_o and Pi in the non-native range is possibly due to elevated marker diversity in the genetic source populations. We refined the previous invasion source region to a ~50km section of northeastern Honshu Island. Outlier detection methods failed to reveal any consistently differentiated loci shared among invaded regions, likely because of the complex A. vermiculophyllum demographic history. Our results reinforce the importance of demographic history, specifically founder effects, in driving genomic variation of invasive populations, even when localized adaptive evolution and reproductive system shifts are observed.

Successful island colonizations are key events to understand range dynamic processes, but studying a young population right after it reaches establishment is a rare opportunity in natural systems. However, the genetic structure of a recently established population may offer unique insights into its colonization history and demographic processes important for a successful colonization. Here, we studied the population genetics of a recently established island population of Eurasian blackbirds (Aves: Turdus merula) located on the island of Heligoland in the German North Sea. Using microsatellites, we genotyped the majority of the island population, including the nestlings, over a four-year period between 2004 and 2007. We also genotyped high numbers of migrants on stopover and mainland individuals, as they are potential founders of the island population. We identified two genetic clusters that comply with the migrating and mainland birds respectively. While most of the island birds belong ...

This collection provides a complete list of convict names and sufficient biographical data to enable unambiguous identification of convicts who were disembarked from convict ship "Marion (3)" at Van Diemen's Land on 1848-01-09

This includes, where known, an estimation of the year of birth, place of birth, where and when convicted, the sentence, the date of arrival in the colony and the convict's age on arrival. The brief convict biographical data provided in this collection serves as an index into the far more extensive set of life course events which are recorded in the prosopgraphy database built by the Founders and Survivors project.

Basic details for this ship: * ship name (as known in VDL records): Marion (3) * sailed date : 1847-09-29 from London * arrival date : 1848-01-09 * population (per Bateson's The Convict Ships): Embarked:299 Men ; Deaths:2 Men ; Landed:292(PP) and ?(NSW) Men

Data for convicts listed in this collection comes from the source which has been determined by Founders and Survivors to form the "base population" for this ship. Further information as to the methodology and the linkage of multiple sources is detailed in the narrative format of the collection. The matching and linkage of additional sources about Tasmanian convict's is the subject of ongoing research. This collection may be repuplished regularly, and in additional formats and with specific user interfaces, to enable public participation in the quality of convict matching and linkage -- see for example the EXPERIMENTAL linkage.htm format for this collection. Linkage for ships arriving at Norfolk Island and Port Philip is incomplete.

This ship's prosopography index is published in a directory named "368.30" (the ship's project id). Three three different file formats provided: -- (default; suitable for web browsing) HTML: world wide web hypertext markup language format which provides a "narrative" view of the collection (index.htm); and -- (structured prosopgraphy: persons and events) XML / TEIp5 : Text Encoding Initiative (version p5) XML format which provides the underlying XML database for this collection (index.xml); and -- Not yet available simple list of convict names in a flat file, tab delimited, suitable for Excel, Stata, SPSS or database usage (index.tab). See notes below.

This collection provides a complete list of convict names and sufficient biographical data to enable unambiguous identification of convicts who were disembarked from convict ship "Thames" at Van Diemen's Land on 1829-11-21

This includes, where known, an estimation of the year of birth, place of birth, where and when convicted, the sentence, the date of arrival in the colony and the convict's age on arrival. The brief convict biographical data provided in this collection serves as an index into the far more extensive set of life course events which are recorded in the prosopgraphy database built by the Founders and Survivors project.

Basic details for this ship: * ship name (as known in VDL records): Thames * sailed date : 1829-07-31 from London * arrival date : 1829-11-21 * population (per Bateson's The Convict Ships): Embarked:160 Men ; Deaths:2 Men ; Landed:158(VDL) Men

Data for convicts listed in this collection comes from the source which has been determined by Founders and Survivors to form the "base population" for this ship. Further information as to the methodology and the linkage of multiple sources is detailed in the narrative format of the collection. The matching and linkage of additional sources about Tasmanian convict's is the subject of ongoing research. This collection may be repuplished regularly, and in additional formats and with specific user interfaces, to enable public participation in the quality of convict matching and linkage -- see for example the EXPERIMENTAL linkage.htm format for this collection. Linkage for ships arriving at Norfolk Island and Port Philip is incomplete.

This ship's prosopography index is published in a directory named "360.14" (the ship's project id). Three three different file formats provided: -- (default; suitable for web browsing) HTML: world wide web hypertext markup language format which provides a "narrative" view of the collection (index.htm); and -- (structured prosopgraphy: persons and events) XML / TEIp5 : Text Encoding Initiative (version p5) XML format which provides the underlying XML database for this collection (index.xml); and -- Not yet available simple list of convict names in a flat file, tab delimited, suitable for Excel, Stata, SPSS or database usage (index.tab). See notes below.

The number and demographic history of colonists can have dramatic consequences for the way in which genetic diversity is distributed and maintained in a metapopulation. The bed bug (Cimex lectularius) is a re-emerging pest species whose close association with humans has led to frequent local extinction and colonisation, i.e. to metapopulation dynamics. Pest control limits the lifespan of sub-populations, causing frequent local extinctions, and human-facilitated dispersal allows the colonisation of empty patches. Founder events often result in drastic reductions in diversity and an increased influence of genetic drift. Coupled with restricted migration this can lead to rapid population differentiation. We therefore predicted strong population structuring. Here, using 21 newly characterised microsatellite markers and Approximate Bayesian Computation (ABC), we investigate simplified versions of two classical models of metapopulation dynamics, in a coalescent framework, in order to estimate the number and genetic composition of founders in the common bed bug. We found very limited diversity within infestations but high degrees of structuring across the city of London, with extreme levels of genetic differentiation between infestations (FST = 0.59). ABC results suggest a common origin of all founders of a given sub-population and that the numbers of colonists were low; implying that even a single mated female is enough to found a new infestation successfully. These patterns of colonisation are close to the predictions of the propagule pool model, where all founders originate from the same parental infestation. These results show that aspects of metapopulation dynamics can be captured in simple models and provide insights that are valuable for the future targeted control of bed bug infestations.

Elucidating the formation of intraspecific genetic variation remains challenging. A powerful but rarely-used approach is to decipher the drivers of demographic dynamics, habitat suitability and linked selection within the context of species’ historical biogeography. We did so using whole genome and fecundity data from 37 populations across the range of a Tibetan bird, the ground tit Pseudopodoces humilis. The spatial pattern of genetic diversity aligned with refugium, bottleneck and founder events experienced by different ground tit populations since the Quaternary glaciation. Contemporary habitat suitability promoted genetic diversity only in highly-isolated regions where populations experienced historical bottlenecks and fragmented habitats, but not in less-isolated regions where refugium and founder populations persisted, highlighting the role of gene flow in maintaining mutation-drift equilibrium. The genetic diversity of neutral loci coupled with fecundity-associated genes declined from refugium to founder populations along a gradient of increased environmental harshness. Our study reveals that present-day genetic diversity is deeply rooted in historical biogeography and offers a general framework for evaluating the macroevolution of intraspecific genetic variation.

The modern history of the United States of America is generally traced back to the founding of Jamestown in the colony of Virginia in 1607. Virginia remained the center of British colonialism in the present-day United States, until the founding of the Plymouth colony in the Northeast in 1620. Virginia remained the largest colony for several decades thereafter, although expansion in the Northeast saw the founding of more individual colonies. The population of the Thirteen colonies first exceeded 100,000 people in the 1660s, and crossed the one million threshold in the 1740s.