scholarly journals Transitional genomes and nutritional role reversals identified for dual symbionts of adelgids (Aphidoidea: Adelgidae)

2021 ◽  
Author(s):  
Dustin T. Dial ◽  
Kathryn M. Weglarz ◽  
Akintunde O. Aremu ◽  
Nathan P. Havill ◽  
Taylor A. Pearson ◽  
...  
Keyword(s):  
Evolutionary History ◽  
Life Cycles ◽  
Fluctuating Selection ◽  
Complex Life Cycles ◽  
History Of ◽  
Sap Feeding ◽  
Selection For ◽  
Gains And Losses ◽  
Conifer Trees ◽  
Plant Sap

AbstractMany plant-sap-feeding insects have maintained a single, obligate, nutritional symbiont over the long history of their lineage. This senior symbiont may be joined by one or more junior symbionts that compensate for gaps in function incurred through genome-degradative forces. Adelgids are sap-sucking insects that feed solely on conifer trees and follow complex life cycles in which the diet fluctuates in nutrient levels. Adelgids are unusual in that both senior and junior symbionts appear to have been replaced repeatedly over their evolutionary history. Genomes can provide clues to understanding symbiont replacements, but only the dual symbionts of hemlock adelgids have been examined thus far. Here, we sequence and compare genomes of four additional dual-symbiont pairs in adelgids. We show that these symbionts are nutritional partners originating from diverse bacterial lineages and exhibiting wide variation in general genome characteristics. Although dual symbionts cooperate to produce nutrients, the balance of contributions varies widely across pairs, and total genome contents reflect a range of ages and degrees of degradation. Most symbionts appear to be in transitional states of genome reduction. Our findings support a hypothesis of periodic symbiont turnover driven by fluctuating selection for nutritional provisioning related to gains and losses of complex life cycles in their hosts.

The diversity and natural history of parasites

2021 ◽  
pp. 19-50
Author(s):  
Paul Schmid-Hempel
Keyword(s):  
Life Cycle ◽  
Natural History ◽  
Food Chain ◽  
Life Cycles ◽  
Growth Phases ◽  
New Host ◽  
Complex Life Cycles ◽  
Parasitic Species ◽  
Parasitic Lifestyle ◽  
History Of

Parasites are more numerous than non-parasitic species and have evolved in virtually all groups of organisms, such as viruses, prokaryotes (bacteria), protozoa, fungi, nematodes, flatworms, acantocephalans, annelids, crustaceans, and arthropods (crustacea, mites, ticks, insects). These groups have adapted to the parasitic lifestyle in very many ways. Evolution towards parasitism has also followed different routes. Initial steps such as phoresy, followed by later consumption of the transport host, are plausible evolutionary routes. Alternatively, formerly free-living forms have become commensals before evolving parasitism. Complex life cycles with several hosts evolved by scenarios such as upward (adding a new host upwards in the food chain), downward, or lateral incorporation, driven by the advantage of extending growth phases within hosts and increasing fecundity. Examples are digenea; other parasites have added vectors to their life cycle.

Defining and Disrupting Species Boundaries in Saccharomyces

2020 ◽  
Vol 74 (1) ◽  
pp. 477-495
Author(s):  
Jasmine Ono ◽  
Duncan Greig ◽  
Primrose J. Boynton
Keyword(s):  
Reproductive Isolation ◽  
Evolutionary History ◽  
Life Cycles ◽  
Sexual Life ◽  
Evolutionary Mechanisms ◽  
History Of ◽  
The One ◽  
Reproductive Isolation Mechanisms ◽  
Evolutionary Consequences ◽  
Isolation Mechanisms

The genus Saccharomyces is an evolutionary paradox. On the one hand, it is composed of at least eight clearly phylogenetically delineated species; these species are reproductively isolated from each other, and hybrids usually cannot complete their sexual life cycles. On the other hand, Saccharomyces species have a long evolutionary history of hybridization, which has phenotypic consequences for adaptation and domestication. A variety of cellular, ecological, and evolutionary mechanisms are responsible for this partial reproductive isolation among Saccharomyces species. These mechanisms have caused the evolution of diverse Saccharomyces species and hybrids, which occupy a variety of wild and domesticated habitats. In this article, we introduce readers to the mechanisms isolating Saccharomyces species, the circumstances in which reproductive isolation mechanisms are effective and ineffective, and the evolutionary consequences of partial reproductive isolation. We discuss both the evolutionary history of the genus Saccharomyces and the human history of taxonomists and biologists struggling with species concepts in this fascinating genus.

The Life-History of Pineus pinifoliae (Fitch) (Homoptera: Phylloxeridae) and its Effect on White Pine

1950 ◽  
Vol 82 (6) ◽  
pp. 117-123 ◽  
Author(s):  
R. E. Balch ◽  
G. R. Underwood
Keyword(s):  
Life History ◽  
Black Spruce ◽  
Life Cycles ◽  
White Pine ◽  
Complex Life Cycles ◽  
Return Migrants ◽  
Winged Form ◽  
Typical Species ◽  
History Of

Pineus pinifoliae (Fitch) belongs to the Adelginae, a group characterized by unusually complex life-cycles. The typical species have at least five distinct forms, one bi-sexual and the others parthenogenetic. They alternate between two coniferous hosts, one of which is always a species of spruce (Picea). Galls are formed on spruce by a modification of the growth of the new shoot.The life-history of P. pinifoliae is only partially known. Patch has reported on observations in Maine which showed that the gall-making form flew from “black spruce” to the needles of white pine and that its offspring settled on the new shoots. She also described a morphologically similar winged form which developed on white-pine shoots and which she believed to be the return migrants. Annand made similar observations in Oregon and gave careful descriptions of three forms: the fundatrix, the gallicola migrans, and the exulis.

Originations and Extinctions in Brachiopods

2001 ◽  
Vol 7 ◽  
pp. 249-258
Author(s):  
Paul Copper
Keyword(s):  
Evolutionary History ◽  
Western Europe ◽  
Cold Water ◽  
Taxonomic Description ◽  
Exponential Increase ◽  
History Of ◽  
The 1960S ◽  
Molecular Relationships ◽  
New Generation ◽  
Gains And Losses

Broad patterns of originations and extinctions of genera, as well as families and higher groups, have always interested those who study the fossil record (e.g., Sepkoski, 1984). They record an important part of the major changeovers, and thus the dynamics, of marine ecosystems over time (Droser et al., 1996; Droser and Sheehan, 1997). This seems especially true for the Paleozoic, when brachiopods were the dominant shelly animals on the seafloor in tropical, temperate, and even cold water settings. Attempts have also been made to determine turnover patterns at the species level (Patzkowsky and Holland, 1997), though this is a much more difficult task, as the validity of species depends a great deal on the skills of the taxonomist. A similar problem is the comparative analysis of diversification data based on a single continent, e.g., North America, as related to others (Miller, 1997a, b); though Laurentia is probably better studied than most areas except western Europe. The exercise of studying broad-scale generic gains and losses for the brachiopods is at the present time preliminary (only three volumes of the revised Treatise are published). The 1965 Treatise contains fewer than 25% of the genera known in detail and described today, with an almost exponential increase in taxonomic description since the 1960s (Williams, 1996). Since then, there have been dramatic revisions and re-interpretations of the evolutionary history of the major brachiopod families, as a new generation of brachiopod workers arrived and matured. We also have a considerably improved knowledge of molecular relationships within the Brachiopoda (Cohen and Gawthrop, 1996). Sound taxonomy is the fundamental basis for sound theoretical discussion of the nature and origins of major changeovers in phyla such as the Brachiopoda. Unfortunately, there are presently relatively few, active brachiopod specialists, as taxonomy has given way to other, more general interests.

scholarly journals Donkey genomes provide new insights into domestication and selection for coat color

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Changfa Wang ◽  
Haijing Li ◽  
Yu Guo ◽  
Jinming Huang ◽  
Yan Sun ◽  
...  
Keyword(s):  
Evolutionary History ◽  
Genetic Basis ◽  
Population Genomics ◽  
De Novo ◽  
Coat Color ◽  
Current Knowledge ◽  
Inhibitory Effect ◽  
Reproductive Management ◽  
History Of ◽  
Selection For

AbstractCurrent knowledge about the evolutionary history of donkeys is still incomplete due to the lack of archeological and whole-genome diversity data. To fill this gap, we have de novo assembled a chromosome-level reference genome of one male Dezhou donkey and analyzed the genomes of 126 domestic donkeys and seven wild asses. Population genomics analyses indicate that donkeys were domesticated in Africa and conclusively show reduced levels of Y chromosome variability and discordant paternal and maternal histories, possibly reflecting the consequences of reproductive management. We also investigate the genetic basis of coat color. While wild asses show diluted gray pigmentation (Dun phenotype), domestic donkeys display non-diluted black or chestnut coat colors (non-Dun) that were probably established during domestication. Here, we show that the non-Dun phenotype is caused by a 1 bp deletion downstream of the TBX3 gene, which decreases the expression of this gene and its inhibitory effect on pigment deposition.

scholarly journals PDZD8 is not the ‘functional ortholog’ of Mmm1, it is a paralog

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 1088 ◽  
Author(s):  
Jeremy G. Wideman ◽  
Dario L. Balacco ◽  
Tim Fieblinger ◽  
Thomas A. Richards
Keyword(s):  
Mammalian Cells ◽  
Evolutionary History ◽  
Phylogenetic Analyses ◽  
Pdz Domain ◽  
Mitochondrial Morphology ◽  
Multiple Gene ◽  
Phylogenetic Data ◽  
History Of ◽  
Gains And Losses ◽  
Complex Evolutionary History

Authors of a recent paper demonstrate that, like ERMES (ER-mitochondria encounter structure) in fungal cells, PDZD8 (PDZ domain containing 8) tethers mitochondria to the ER in mammalian cells. However, identifying PDZD8 as a “functional ortholog” of yeast Mmm1 (maintenance of mitochondrial morphology protein 1) is at odds with the phylogenetic data. PDZD8 and Mmm1 are paralogs, not orthologs, which affects the interpretation of the data with respect to the evolution of ER-mitochondria tethering. Our phylogenetic analyses show that PDZD8 co-occurs with ERMES components in lineages closely related to animals solidifying its identity as a paralog of Mmm1. Additionally, we identify two related paralogs, one specific to flagellated fungi, and one present only in unicellular relatives of animals. These results point to a complex evolutionary history of ER-mitochondria tethering involving multiple gene gains and losses in the lineage leading to animals and fungi.

scholarly journals Bird size with dinosaur-level cancer defences: can evolutionary lags during miniaturisation explain cancer robustness in birds?

2020 ◽  
Author(s):  
E. Yagmur Erten ◽  
Marc Tollis ◽  
Hanna Kokko
Keyword(s):  
Body Size ◽  
Cancer Risk ◽  
Evolutionary History ◽  
Effective Population ◽  
Extrinsic Mortality ◽  
Cell Divisions ◽  
Large Size ◽  
History Of ◽  
Cancer Suppression ◽  
Gains And Losses

AbstractAn increased appreciation of the ubiquity of cancer risk across the tree of life means we also need to understand the more robust cancer defences some species seem to have. Peto’s paradox, the finding that large-bodied species do not suffer from more cancer even if their lives require far more cell divisions than those of small species, can be explained if large size selects for better cancer defences. Since birds live longer than non-flying mammals of an equivalent body size, and birds are descendants of moderate-sized dinosaurs, we ask whether ancestral cancer defence innovations are retained if body size shrinks in an evolutionary lineage. Our model derives selection coefficients and fixation events for gains and losses of cancer defence innovations over macroevolutionary time, based on known relationships between body size, intrinsic cancer risk, extrinsic mortality (modulated by flight ability) and effective population size. We show that evolutionary lags can, under certain assumptions, explain why birds, descendants of relatively large bodied dinosaurs, retain low cancer risk. Counterintuitively, it is possible for a bird to be ‘too robust’ for its own good: excessive cancer suppression can take away from reproductive success. On the other hand, an evolutionary history of good cancer defences may also enable birds to reap the lifespan-increasing benefits of other innovations such as flight.

Why did some ichthyosaurs have such large eyes?

2002 ◽  
Vol 205 (4) ◽  
pp. 439-441
Author(s):  
Stuart Humphries ◽  
Graeme D. Ruxton
Keyword(s):  
Marine Mammals ◽  
Evolutionary History ◽  
Ecological Factors ◽  
Great Depth ◽  
Low Light ◽  
Deep Diving ◽  
Eye Size ◽  
History Of ◽  
Simultaneous Selection ◽  
Selection For

SUMMARY Many species of extinct marine ichthyosaurs had much larger eyes for their body size than would be expected of extant marine mammals and reptiles. Sensitivity to low light at great depth for the deep-diving genus Ophthalmosaurus has recently been suggested as the reason for the large eyes of these animals. Here, we discuss the implications for vision at such depths and consider other optical factors determining eye size. We suggest that the large eyes of ichthyosaurs are more likely to be the result of simultaneous selection for both sensitivity to low light and visual acuity. The importance of the evolutionary history of extant marine mammals and extinct ichthyosaurs is discussed, as are ecological factors driving both acuity and sensitivity.

scholarly journals The evolutionary history of siphonophore tentilla: Novelties, convergence, and integration

2021 ◽  
Author(s):  
Alejandro Damian-Serrano ◽  
Steven H D Haddock ◽  
Casey W Dunn
Keyword(s):  
High Speed ◽  
Evolutionary History ◽  
Prey Capture ◽  
Feeding Habits ◽  
Morphological Diversity ◽  
Morphological Characters ◽  
Low Dimensionality ◽  
History Of ◽  
Gains And Losses ◽  
Character Correlations

Abstract Siphonophores are free-living predatory colonial hydrozoan cnidarians found in every region of the ocean. Siphonophore tentilla (tentacle side branches) are unique biological structures for prey capture, composed of a complex arrangement of cnidocytes (stinging cells) bearing different types of nematocysts (stinging capsules) and auxiliary structures. Tentilla present an extensive morphological and functional diversity across species. While associations between tentillum form and diet have been reported, the evolutionary history giving rise to this morphological diversity is largely unexplored. Here we examine the evolutionary gains and losses of novel tentillum substructures and nematocyst types on the most recent siphonophore phylogeny. Tentilla have a precisely coordinated high-speed strike mechanism of synchronous unwinding and nematocyst discharge. Here we characterize the kinematic diversity of this prey capture reaction using high-speed video and find relationships with morphological characters. Since tentillum discharge occurs in synchrony across a broad morphological diversity, we evaluate how phenotypic integration is maintaining character correlations across evolutionary time. We found that the tentillum morphospace has low dimensionality, identified instances of heterochrony and morphological convergence, and generated hypotheses on the diets of understudied siphonophore species. Our findings indicate that siphonophore tentilla are phenotypically integrated structures with a complex evolutionary history leading to a phylogenetically-structured diversity of forms which are predictive of kinematic performance and feeding habits.

Elaborating the role of reflection and individual differences in the study of folk-economic beliefs

2018 ◽  
Vol 41 ◽  
Author(s):  
Kevin Arceneaux
Keyword(s):  
Decision Making ◽  
Individual Differences ◽  
Cognitive Processes ◽  
Evolutionary History ◽  
Behavioral Responses ◽  
History Of ◽  
Economic Beliefs

AbstractIntuitions guide decision-making, and looking to the evolutionary history of humans illuminates why some behavioral responses are more intuitive than others. Yet a place remains for cognitive processes to second-guess intuitive responses – that is, to be reflective – and individual differences abound in automatic, intuitive processing as well.

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