scholarly journals Transposable element abundance correlates with mode of transmission in microsporidian parasites

2020 ◽  
Author(s):  
Nathalia Rammé Medeiros de Albuquerque ◽  
Dieter Ebert ◽  
Karen Luisa Haag
Keyword(s):  
Natural Selection ◽  
Transposable Element ◽  
Genome Size ◽  
Vertical Transmission ◽  
Size Range ◽  
Element Abundance ◽  
Population Bottlenecks ◽  
Parasitic Lifestyle ◽  
Mode Of Transmission ◽  
Transposable Element Abundance

Abstract The extreme genome reduction and physiological simplicity of some microsporidia has been attributed to their intracellular, obligate parasitic lifestyle. Although not all microsporidian genomes are small (size range from about 2 to 50 MB), it is suggested that the size of their genomes has been streamlined by natural selection. We explore the hypothesis that vertical transmission in microsporidia produces population bottlenecks, and thus reduces the effectiveness of natural selection. Here we compare the transposable element (TE) content of 47 microsporidian genomes, and show that genome size is positively correlated with the amount of TEs, and that species that experience vertical transmission have larger genomes with higher proportion of TEs. Our findings are consistent with earlier studies inferring that nonadaptive processes play an important role in microsporidian evolution.

scholarly journals Transposable element abundance correlates with mode of transmission in microsporidian parasites

2020 ◽  
Author(s):  
Nathalia Rammé Medeiros de Albuquerque ◽  
Dieter Ebert ◽  
Karen Luisa Haag
Keyword(s):  
Natural Selection ◽  
Transposable Element ◽  
Genome Size ◽  
Vertical Transmission ◽  
Size Range ◽  
Alternative Hypothesis ◽  
Element Abundance ◽  
Population Bottlenecks ◽  
Parasitic Lifestyle ◽  
Transposable Element Abundance

Abstract The extreme genome reduction and physiological simplicity of some microsporidia has been attributed to their intracellular, obligate parasitic lifestyle. Although not all microsporidian genomes are small–the known size range goes from about 2 to 50 MB–it is widely accepted that microsporidian genome size has been streamlined by natural selection. We explore an alternative hypothesis for microsporidian genome diversification, i.e ., that vertical transmission in microsporidia likely produces population bottlenecks, reducing the effectiveness of natural selection. We compared the transposable element (TE) content of 47 microsporidian genomes, and showed that genome size is positively correlated with the amount of TEs, and that species that experience vertical transmission have larger genomes with higher proportion of TEs. Our findings are consistent with earlier studies inferring that nonadaptive processes play an important role in microsporidian evolution.

scholarly journals Transposable element abundance correlates with mode of transmission in microsporidian parasites

Mobile DNA ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Nathalia Rammé Medeiros de Albuquerque ◽  
Dieter Ebert ◽  
Karen Luisa Haag
Keyword(s):  
Transposable Element ◽  
Element Abundance ◽  
Mode Of Transmission ◽  
Transposable Element Abundance

scholarly journals No evidence that sex and transposable elements drive genome size variation in evening primroses

2014 ◽  
Author(s):  
J Arvid Agren ◽  
Stephan Greiner ◽  
Marc TJ Johnson ◽  
Stephen I Wright
Keyword(s):  
Transposable Elements ◽  
Transposable Element ◽  
Sexual Reproduction ◽  
Genome Size ◽  
Reproductive System ◽  
Size Variation ◽  
Comparative Approach ◽  
Element Abundance ◽  
Whole Genome ◽  
Genome Size Variation

Genome size varies dramatically across species, but despite an abundance of attention there is little agreement on the relative contributions of selective and neutral processes in governing this variation. The rate of sexual reproduction can potentially play an important role in genome size evolution because of its effect on the efficacy of selection and transmission of transposable elements. Here, we used a phylogenetic comparative approach and whole genome sequencing to investigate the contribution of sex and transposable element content to genome size variation in the evening primrose (Oenothera) genus. We determined genome size using flow cytometry from 30 Oenothera species of varying reproductive system and find that variation in sexual/asexual reproduction cannot explain the almost two-fold variation in genome size. Moreover, using whole genome sequences of three species of varying genome sizes and reproductive system, we found that genome size was not associated with transposable element abundance; instead the larger genomes had a higher abundance of simple sequence repeats. Although it has long been clear that sexual reproduction may affect various aspects of genome evolution in general and transposable element evolution in particular, it does not appear to have played a major role in the evening primroses.

Inbreeding reduces reproductive fitness

2017 ◽  
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark D. B. Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Natural Selection ◽  
Inbreeding Depression ◽  
Reproductive Fitness ◽  
Heterozygote Advantage ◽  
Small Populations ◽  
Population Bottlenecks ◽  
Risk Of Extinction ◽  
Survival And Reproduction

The harmful impacts of inbreeding are generally greater in species that naturally outbreed compared to those in inbreeding species, greater in stressful than benign environments, greater for fitness than peripheral traits, and greater for total fitness compared to its individual components. Inbreeding reduces survival and reproduction (i.e., it causes inbreeding depression), and thereby increases the risk of extinction. Inbreeding depression is due to increased homozygosity for harmful alleles and at loci exhibiting heterozygote advantage. Natural selection may remove (purge) the alleles that cause inbreeding depression, especially following inbreeding or population bottlenecks, but it has limited effects in small populations and usually does not completely eliminate inbreeding depression. Inbreeding depression is nearly universal in sexually reproducing organisms that are diploid or have higher ploidies.

scholarly journals Genome size correlates with reproductive fitness in seed beetles

2015 ◽  
Vol 282 (1815) ◽  
pp. 20151421 ◽  
Author(s):  
Göran Arnqvist ◽  
Ahmed Sayadi ◽  
Elina Immonen ◽  
Cosima Hotzy ◽  
Daniel Rankin ◽  
...  
Keyword(s):  
Life History ◽  
Natural Selection ◽  
Genome Size ◽  
Evolutionary Biology ◽  
Large Scale ◽  
Life History Traits ◽  
Single Species ◽  
Reproductive Fitness ◽  
Correlated Evolution ◽  
Seed Beetles

The ultimate cause of genome size (GS) evolution in eukaryotes remains a major and unresolved puzzle in evolutionary biology. Large-scale comparative studies have failed to find consistent correlations between GS and organismal properties, resulting in the ‘ C -value paradox’. Current hypotheses for the evolution of GS are based either on the balance between mutational events and drift or on natural selection acting upon standing genetic variation in GS. It is, however, currently very difficult to evaluate the role of selection because within-species studies that relate variation in life-history traits to variation in GS are very rare. Here, we report phylogenetic comparative analyses of GS evolution in seed beetles at two distinct taxonomic scales, which combines replicated estimation of GS with experimental assays of life-history traits and reproductive fitness. GS showed rapid and bidirectional evolution across species, but did not show correlated evolution with any of several indices of the relative importance of genetic drift. Within a single species, GS varied by 4–5% across populations and showed positive correlated evolution with independent estimates of male and female reproductive fitness. Collectively, the phylogenetic pattern of GS diversification across and within species in conjunction with the pattern of correlated evolution between GS and fitness provide novel support for the tenet that natural selection plays a key role in shaping GS evolution.

scholarly journals Relaxed natural selection alone does not permit transposable element expansion within 4,000 generations in Escherichia coli

Genetica ◽  
2011 ◽  
Vol 139 (7) ◽  
pp. 895-902 ◽  
Author(s):  
Gordon R. Plague ◽  
Kevin M. Dougherty ◽  
Krystal S. Boodram ◽  
Samantha E. Boustani ◽  
Huansheng Cao ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Natural Selection ◽  
Transposable Element

scholarly journals Genome size versus geographic range size in birds

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10868
Author(s):  
Beata Grzywacz ◽  
Piotr Skórka
Keyword(s):  
Natural Selection ◽  
Chromosome Number ◽  
Genome Size ◽  
Body Mass ◽  
Generalized Least Squares ◽  
Geographic Range ◽  
Range Size ◽  
Geographic Ranges ◽  
Brain Mass ◽  
Terrestrial Vertebrates

Why do some species occur in small, restricted areas, while others are distributed globally? Environmental heterogeneity increases with area and so does the number of species. Hence, diverse biotic and abiotic conditions across large ranges may lead to specific adaptations that are often linked to a species’ genome size and chromosome number. Therefore, a positive association between genome size and geographic range is anticipated. Moreover, high cognitive ability in organisms would be favored by natural selection to cope with the dynamic conditions within large geographic ranges. Here, we tested these hypotheses in birds—the most mobile terrestrial vertebrates—and accounted for the effects of various confounding variables, such as body mass, relative brain mass, and geographic latitude. Using phylogenetic generalized least squares and phylogenetic confirmatory path analysis, we demonstrated that range size is positively associated with bird genome size but probably not with chromosome number. Moreover, relative brain mass had no effect on range size, whereas body mass had a possible weak and negative effect, and range size was larger at higher geographic latitudes. However, our models did not fully explain the overall variation in range size. Hence, natural selection may impose larger genomes in birds with larger geographic ranges, although there may be additional explanations for this phenomenon.

scholarly journals Possible Early Vertical Transmission of COVID-19 from an Infected Pregnant Female to Her Neonate: A Case Report

2020 ◽  
Author(s):  
Tapas Bandyopadhyay ◽  
Abhinav Sharma ◽  
Pratima Kumari ◽  
Arti Maria ◽  
Rahul Choudhary
Keyword(s):  
Public Health ◽  
Vertical Transmission ◽  
Antibody Test ◽  
Public Health Emergency ◽  
Pregnant Female ◽  
Rare Entity ◽  
Rt Pcr ◽  
Igg Antibody ◽  
Mode Of Transmission ◽  
Reported Data

Abstract Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-19) has emerged as a public health emergency in recent times. The reported data on the mode of transmission of coronavirus disease 2019 (COVID-19) are largely through contact, droplet, airborne and fomite transmission methods with vertical transmission being a rare entity. We hereby report a case of a probable vertical transmission of SARS-CoV-19 from an infected pregnant female to her neonate. The transmission has been confirmed by a positive RT-PCR at 16 h of life along with a positive IgG antibody test for SARS-CoV-19 in the baby and after excluding the possible environmental contamination of the sample. The baby was asymptomatic during the course of hospital stay and was discharged from the facility on Day 9 of life.

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