Microevolution and the Skeletal Traits of a Middle Archaic Burial: Metric and Multivariate Comparison to Paleoindians and Modern Amerindians

Skeletal remains recovered and analyzed from Archaic and Paleoindian periods demonstrate less pronounced Asiatic/Sinodont features that distinguish them from present day Amerindians. This paper describes the metric and nonmetric traits that link a Middle Plains Archaic male (radiocarbon dated to 2220-2500 B. C.), found near Sidney, Nebraska, to Sinodonts, Sundadonts, and Paleoindians. Metrically, the Sidney male differs from Late Prehistoric and Historic Mandan and Arikara males (1500 to 1830 A.D.) from the same region in cranial vault height (auricular height p ≤ .02 basion-porion height p ≤ .07). His cranium is longer and higher (acrocranic Cranial Breadth-Height Index) than that of the more highly derived Mandan and Arikara males. Several of the Sidney male’s cranial and femoral traits show a blend of Amerindian and earlier protomongoloid traits, distinguishable from recent Amerindian populations. These traits suggest affiliation to a common Eurasian progenitor for Sinodonts, Sundadonts, and Paleoindians, and support the hypothesis that Plains Amerindians descended from the earliest wave of Paleoindians who crossed the Bering Straits. Tracing microevolutionary changes across time is a challenging, incremental process, not yet resolved by the limited Paleoindian and Archaic skeletal remains discovered to date. However, the intermediate skeletal characteristics of the Sidney male indicate gradual adaptation and suggest that natural selection most strongly influenced the adaptation of Plains peoples. Information presented here increases the database needed for future investigations of microevolution, gene flow patterns and the cultural history that may someday link early Archaic populations and Paleoindians to specific tribes among the modern Plains Amerindians.

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Population structure, gene flow and natural selection in populations of Euphydryas phaeton

Heredity ◽

10.1038/hdy.1975.50 ◽

1975 ◽

Vol 34 (3) ◽

pp. 407-415 ◽

Cited By ~ 9

Author(s):

Peter F Brussard ◽

A Thomas Vawter

Keyword(s):

Population Structure ◽

Gene Flow ◽

Natural Selection

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A last stand in the Po valley: genetic structure and gene flow patterns in Ulmus minor and U. pumila

Annals of Botany ◽

10.1093/aob/mcu256 ◽

2015 ◽

Vol 115 (4) ◽

pp. 683-692 ◽

Cited By ~ 6

Author(s):

B. Bertolasi ◽

C. Leonarduzzi ◽

A. Piotti ◽

S. Leonardi ◽

L. Zago ◽

...

Keyword(s):

Gene Flow ◽

Genetic Structure ◽

Flow Patterns ◽

Ulmus Minor ◽

Po Valley

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Ecological Divergence and the Origins of Intrinsic Postmating Isolation with Gene Flow

International Journal of Ecology ◽

10.1155/2011/435357 ◽

2011 ◽

Vol 2011 ◽

pp. 1-15 ◽

Cited By ~ 24

Author(s):

Aneil F. Agrawal ◽

Jeffrey L. Feder ◽

Patrik Nosil

Keyword(s):

Linkage Disequilibrium ◽

Gene Flow ◽

Natural Selection ◽

Theoretical Models ◽

Ecological Speciation ◽

Divergent Selection ◽

Postmating Isolation ◽

Divergent Natural Selection ◽

Mathematical Exploration ◽

Neutral Gene

The evolution of intrinsic postmating isolation has received much attention, both historically and in recent studies of speciation genes. Intrinsic isolation often stems from between-locus genetic incompatibilities, where alleles that function well within species are incompatible with one another when brought together in the genome of a hybrid. It can be difficult for such incompatibilities to originate when populations diverge with gene flow, because deleterious genotypic combinations will be created and then purged by selection. However, it has been argued that if genes underlying incompatibilities are themselves subject to divergent selection, then they might overcome gene flow to diverge between populations, resulting in the origin of incompatibilities. Nonetheless, there has been little explicit mathematical exploration of such scenarios for the origin of intrinsic incompatibilities during ecological speciation with gene flow. Here we explore theoretical models for the origin of intrinsic isolation where genes subject to divergent natural selection also affect intrinsic isolation, either directly or via linkage disequilibrium with other loci. Such genes indeed overcome gene flow, diverge between populations, and thus result in the evolution of intrinsic isolation. We also examine barriers to neutral gene flow. Surprisingly, we find that intrinsic isolation sometimes weakens this barrier, by impeding differentiation via ecologically based divergent selection.

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Multiple incursion pathways for Helicoverpa armigera in Brazil show its genetic diversity spreading in a connected world

10.1101/762229 ◽

2019 ◽

Cited By ~ 1

Author(s):

Jonas A. Arnemann ◽

Stephen H. Roxburgh ◽

Tom Walsh ◽

Jerson V.C. Guedes ◽

Karl H.J. Gordon ◽

...

Keyword(s):

Spatial Distribution ◽

Gene Flow ◽

South America ◽

New World ◽

Flow Patterns ◽

South American ◽

Southern Brazil ◽

American Continent ◽

Central Brazil ◽

South American Continent

AbstractThe Old World cotton bollworm Helicoverpa armigera was first detected in Brazil with subsequent reports from Paraguay, Argentina, Bolivia, and Uruguay. This pattern suggests that the H. armigera spread across the South American continent following incursions into northern/central Brazil, however, this hypothesis has not been tested. Here we compare northern and central Brazilian H. armigera mtDNA COI haplotypes with those from southern Brazil, Uruguay, Argentina, and Paraguay. We infer spatial genetic and gene flow patterns of this dispersive pest in the agricultural landscape of South America. We show that the spatial distribution of H. armigera mtDNA haplotypes and its inferred gene flow patterns in the southwestern region of South America exhibited signatures inconsistent with a single incursion hypothesis. Simulations on spatial distribution patterns show that the detection of rare and/or the absence of dominant mtDNA haplotypes in southern H. armigera populations are inconsistent with genetic signatures observed in northern and central Brazil. Incursions of H. armigera into the New World are therefore likely to have involved independent events in northern/central Brazil, and southern Brazil/Uruguay-Argentina-Paraguay. This study demonstrates the significant biosecurity challenges facing the South American continent, and highlights alternate pathways for introductions of alien species into the New World.

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Seed set and gene flow patterns in an experimental population of an endangered heterostylous herb with controlled local opposite-morph density

Functional Ecology ◽

10.1046/j.1365-2435.2003.00773.x ◽

2003 ◽

Vol 17 (5) ◽

pp. 680-689 ◽

Cited By ~ 25

Author(s):

F. Ishihama ◽

C. Nakano ◽

S. Ueno ◽

M. Ajima ◽

Y. Tsumura ◽

...

Keyword(s):

Gene Flow ◽

Seed Set ◽

Flow Patterns ◽

Experimental Population

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Multiple incursion pathways for Helicoverpa armigera in Brazil show its genetic diversity spreading in a connected world

Scientific Reports ◽

10.1038/s41598-019-55919-9 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 6

Author(s):

Jonas Andre Arnemann ◽

Stephen Roxburgh ◽

Tom Walsh ◽

Jerson Guedes ◽

Karl Gordon ◽

...

Keyword(s):

Spatial Distribution ◽

Gene Flow ◽

South America ◽

New World ◽

Flow Patterns ◽

South American ◽

Southern Brazil ◽

American Continent ◽

Central Brazil ◽

South American Continent

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Patterns of Genome-Wide Variation, Population Differentiation and SNP Discovery of the Red Banded Stink Bug (Piezodorus guildinii)

Scientific Reports ◽

10.1038/s41598-019-50999-z ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Maria I. Zucchi ◽

Erick M. G. Cordeiro ◽

Clint Allen ◽

Mariana Novello ◽

João Paulo Gomes Viana ◽

...

Keyword(s):

Gene Flow ◽

Natural Selection ◽

Genetic Structure ◽

Insect Pests ◽

Geographic Origin ◽

The United States ◽

Basic Knowledge ◽

Stink Bug ◽

Mixed Ancestry ◽

Significant Genetic Structure

Abstract Unravelling the details of range expansion and ecological dominance shifts of insect pests has been challenging due to the lack of basic knowledge about population structure, gene flow, and most importantly, how natural selection is affecting the adaptive process. Piezodous guildinii is an emerging pest of soybean in the southern region of the United States, and increasingly important in Brazil in recent years. However, the reasons P. guildinii is gradually becoming more of a problem are questions still mostly unanswered. Here, we have genotyped P. guildinii samples and discovered 1,337 loci containing 4,083 variant sites SNPs that were used to estimate genetic structure and to identify gene candidates under natural selection. Our results revealed the existence of a significant genetic structure separating populations according to their broad geographic origin, i.e., U.S. and Brazil, supported by AMOVA (FGT = 0.26), STRUCTURE, PCA, and FST analyses. High levels of gene flow or coancestry within groups (i.e., within countries) can be inferred from the data, and no spatial pattern was apparent at the finer scale in Brazil. Samples from different seasons show more heterogeneous compositions suggesting mixed ancestry and a more complex dynamic. Lastly, we were able to detect and successfully annotated 123 GBS loci (10.5%) under positive selection. The gene ontology (GO) analysis implicated candidate genes under selection with genome reorganization, neuropeptides, and energy mobilization. We discuss how these findings could be related to recent outbreaks and suggest how new efforts directed to better understand P. guildinii population dynamics.

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Host races in plant–feeding insects and their importance in sympatric speciation

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2002.1059 ◽

2002 ◽

Vol 357 (1420) ◽

pp. 471-492 ◽

Cited By ~ 616

Author(s):

Michele Drès ◽

James Mallet

Keyword(s):

Linkage Disequilibrium ◽

Gene Flow ◽

Natural Selection ◽

Reproductive Isolation ◽

Sympatric Speciation ◽

Accurate Information ◽

Sympatric Populations ◽

New Host ◽

Host Races ◽

Plant Feeding

The existence of a continuous array of sympatric biotypes—from polymorphisms, through ecological or host races with increasing reproductive isolation, to good species—can provide strong evidence for a continuous route to sympatric speciation via natural selection. Host races in plant–feeding insects, in particular, have often been used as evidence for the probability of sympatric speciation. Here, we provide verifiable criteria to distinguish host races from other biotypes: in brief, host races are genetically differentiated, sympatric populations of parasites that use different hosts and between which there is appreciable gene flow. We recognize host races as kinds of species that regularly exchange genes with other species at a rate of more than ca . 1% per generation, rather than as fundamentally distinct taxa. Host races provide a convenient, although admittedly somewhat arbitrary intermediate stage along the speciation continuum. They are a heuristic device to aid in evaluating the probability of speciation by natural selection, particularly in sympatry. Speciation is thereby envisaged as having two phases: (i) the evolution of host races from within polymorphic, panmictic populations; and (ii) further reduction of gene flow between host races until the diverging populations can become generally accepted as species. We apply this criterion to 21 putative host race systems. Of these, only three are unambiguously classified as host races, but a further eight are strong candidates that merely lack accurate information on rates of hybridization or gene flow. Thus, over one–half of the cases that we review are probably or certainly host races, under our definition. Our review of the data favours the idea of sympatric speciation via host shift for three major reasons: (i) the evolution of assortative mating as a pleiotropic by–product of adaptation to a new host seems likely, even in cases where mating occurs away from the host; (ii) stable genetic differences in half of the cases attest to the power of natural selection to maintain multilocus polymorphisms with substantial linkage disequilibrium, in spite of probable gene flow; and (iii) this linkage disequilibrium should permit additional host adaptation, leading to further reproductive isolation via pleiotropy, and also provides conditions suitable for adaptive evolution of mate choice (reinforcement) to cause still further reductions in gene flow. Current data are too sparse to rule out a cryptic discontinuity in the apparently stable sympatric route from host–associated polymorphism to host–associated species, but such a hiatus seems unlikely on present evidence. Finally, we discuss applications of an understanding of host races in conservation and in managing adaptation by pests to control strategies, including those involving biological control or transgenic parasite–resistant plants.

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