Children Die, Air Pollution Continues

The human species has evolved thanks in part to our ability to learn and solve problems, and now we as a race must solve a universal problem, air pollution. Coal, electricity, automobiles, gasoline, and nuclear power – our proud innovations – are now poisoning the air we breathe. And our children are the ones who reap the worst effects from what humanity has sown. They are the ones closest to the ground, so they consume more automobile toxins. They are the ones who breathe the fastest, faster than adults, thus resulting in consuming polluted air the quickest. They are the ones who are completely innocent of the air they breathe: 100% of children who are born into this world are blameless, yet 90% of them reap the benefits. How are these children affected by breathing polluted air? They may experience respiratory problems, heart issues, and, most importantly, cognitive functioning issues. Children who intake polluted air are at a higher risk for decreased levels of cognitive functioning; in other words, our children, our future, are becoming mentally handicapped by the very air we hope they fix in the future. Thus, humanity must change its current pollutive trajectory by any number of health-conscious countermeasures: raise fuel-economy standards, eliminate coal production and use, and limit CO2 emissions from nuclear plants and other sources. For the future to live, the present-day adult generation must change their pollutive habits

Gene flow persists millions of years after speciation in Heliconius butterflies

<p>Abstract</p> <p>Background</p> <p>Hybridization, or the interbreeding of two species, is now recognized as an important process in the evolution of many organisms. However, the extent to which hybridization results in the transfer of genetic material across the species boundary (introgression) remains unknown in many systems, as does the length of time after initial divergence that the species boundary remains porous to such gene flow.</p> <p>Results</p> <p>Here I use genome-wide genotypic and DNA sequence data to show that there is introgression and admixture between the <it>melpomene</it>/<it>cydno </it>and silvaniform clades of the butterfly genus <it>Heliconius</it>, groups that separated from one another as many as 30 million generations ago. Estimates of historical migration based on 523 DNA sequences from 14 genes suggest unidirectional gene flow from the <it>melpomene</it>/<it>cydno </it>clade into the silvaniform clade. Furthermore, genetic clustering based on 520 amplified fragment length polymorphisms (AFLPs) identified multiple individuals of mixed ancestry showing that introgression is on-going.</p> <p>Conclusion</p> <p>These results demonstrate that genomes can remain porous to gene flow very long after initial divergence. This, in turn, greatly expands the evolutionary potential afforded by introgression. Phenotypic and species diversity in a wide variety of organisms, including <it>Heliconius</it>, have likely arisen from introgressive hybridization. Evidence for continuous gene flow over millions of years points to introgression as a potentially important source of genetic variation to fuel the evolution of novel forms.</p

A shared genetic basis of mimicry across swallowtail butterflies points to ancestral co-option of doublesex

Uncovering whether convergent adaptations share a genetic basis is consequential for understanding the evolution of phenotypic diversity. This information can help us understand the extent to which shared ancestry or independent evolution shape adaptive phenotypes. In this study, we first ask whether the same genes underlie polymorphic mimicry in Papilio swallowtail butterflies. By comparing signatures of genetic variation between polymorphic and monomorphic species, we then investigate how ancestral variation, hybridization, and independent evolution contributed to wing pattern diversity in this group. We report that a single gene, doublesex (dsx), controls mimicry across multiple taxa, but with species-specific patterns of genetic differentiation and linkage disequilibrium. In contrast to widespread examples of phenotypic evolution driven by introgression, our analyses reveal distinct mimicry alleles. We conclude that mimicry evolution in this group was likely facilitated by ancestral polymorphism resulting from early co-option of dsx as a mimicry locus, and that evolutionary turnover of dsx alleles may underlie the wing pattern diversity of extant polymorphic and monomorphic lineages

Monarch butterflies use an environmentally sensitive, internal timer to control overwintering dynamics

The monarch butterfly (Danaus plexippus) complements its iconic migration with diapause, a hormonally controlled developmental programme that contributes to winter survival at overwintering sites. Although timing is a critical adaptive feature of diapause, how environmental cues are integrated with genetically‐determined physiological mechanisms to time diapause development, particularly termination, is not well understood. In a design that subjected western North American monarchs to different environmental chamber conditions over time, we modularized constituent components of an environmentally‐controlled, internal diapause termination timer. Using comparative transcriptomics, we identified molecular controllers of these specific diapause termination components. Calcium signalling mediated environmental sensitivity of the diapause timer, and we speculate that it is a key integrator of environmental condition (cold temperature) with downstream hormonal control of diapause. Juvenile hormone (JH) signalling changed spontaneously in diapause‐inducing conditions, capacitating response to future environmental condition. Although JH is a major target of the internal timer, it is not itself the timer. Epigenetic mechanisms are implicated to be the proximate timing mechanism. Ecdysteroid, JH, and insulin/insulin‐like peptide signalling are major targets of the diapause programme used to control response to permissive environmental conditions. Understanding the environmental and physiological mechanisms of diapause termination sheds light on fundamental properties of biological timing, and also helps inform expectations for how monarch populations may respond to future climate change.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151901/1/mec15178_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151901/2/mec15178.pd

Monarch butterflies use an environmentally sensitive, internal timer to control overwintering dynamics

The monarch butterfly (Danaus plexippus) complements its iconic migration with diapause, a hormonally controlled developmental programme that contributes to winter survival at overwintering sites. Although timing is a critical adaptive feature of diapause, how environmental cues are integrated with genetically‐determined physiological mechanisms to time diapause development, particularly termination, is not well understood. In a design that subjected western North American monarchs to different environmental chamber conditions over time, we modularized constituent components of an environmentally‐controlled, internal diapause termination timer. Using comparative transcriptomics, we identified molecular controllers of these specific diapause termination components. Calcium signalling mediated environmental sensitivity of the diapause timer, and we speculate that it is a key integrator of environmental condition (cold temperature) with downstream hormonal control of diapause. Juvenile hormone (JH) signalling changed spontaneously in diapause‐inducing conditions, capacitating response to future environmental condition. Although JH is a major target of the internal timer, it is not itself the timer. Epigenetic mechanisms are implicated to be the proximate timing mechanism. Ecdysteroid, JH, and insulin/insulin‐like peptide signalling are major targets of the diapause programme used to control response to permissive environmental conditions. Understanding the environmental and physiological mechanisms of diapause termination sheds light on fundamental properties of biological timing, and also helps inform expectations for how monarch populations may respond to future climate change.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151901/1/mec15178_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151901/2/mec15178.pd

Convocation

The origins of phenotypic variation within mimetic Heliconius butterflies have long fascinated biologists and naturalists. However, the evolutionary processes that have generated this extraordinary diversity remain puzzling. Here we examine intraspecific variation across Heliconius cydno diversification and compare this variation to that within the closely related H. melpomene and H. timareta radiations. Our data, which consist of both mtDNA and genome scan from nearly 2250 AFLP loci, reveal a complex history of differentiation and admixture at different geographic scales. Both mtDNA and AFLP phylogenies suggest that H. timareta and H. cydno are probably geographic extremes of the same radiation that likely diverged from H. melpomene during the Pliocene-Pleistocene boundary. MtDNA suggest that this radiation originated in Central America or the Northwestern region of South America, with a subsequent colonization of the eastern and western slopes of the Andes. Our genome-scan data indicate significant admixture among sympatric H. cydno/H.timareta and H. melpomene populations across the extensive geographic ranges of the two radiations. Within H. cydno, both mtDNA and AFLP data indicate significant population structure at local scales, with strong genetic differences even among adjacent H. cydno color pattern races. These genetic patterns highlight the importance of past geoclimatic events, intraspecific gene flow, and local population differentiation in the origin and establishment of new adaptive forms

Neonatal Host Defense against Staphylococcal Infections

Preterm infants are especially susceptible to late-onset sepsis that is often due to Gram-positive bacterial infections resulting in substantial morbidity and mortality. Herein, we will describe neonatal innate immunity to Staphylococcus spp. comparing differences between preterm and full-term newborns with adults. Newborn innate immunity is distinct demonstrating diminished skin integrity, impaired Th1-polarizing responses, low complement levels, and diminished expression of plasma antimicrobial proteins and peptides, especially in preterm newborns. Characterization of distinct aspects of the neonatal immune response is defining novel approaches to enhance host defense to prevent and/or treat staphylococcal infection in this vulnerable population

Phylogeography and Sexual Macrocyst Formation in the Social Amoeba DictyosteliumGiganteumDictyostelium Giganteum

Background: Microorganisms are ubiquitous, yet we are only beginning to understand their diversity and population structure. Social amoebae (Dictyostelia) are a diverse group of unicellular eukaryotic microbes that display a unique social behaviour upon starvation in which cells congregate and then some die to help others survive and disperse. The genetic relationships among co-occurring cells have a major influence on the evolution of social traits and recent population genetic analysis found extensive genetic variation and possible cryptic speciation in one dictyostelid species $(Dictyostelium purpureum)$. To further characterize the interplay among genetic variation, species boundaries, social behaviour, and reproductive isolation in the Dictyostelia, we conducted phylogenetic analyses and mating experiments with the geographically widespread social amoeba $Dictyostelium giganteum$. Results: We sequenced approximately 4,000 basepairs of the nuclear ribosomal DNA from 24 isolates collected from Texas, Michigan, Massachusetts, Virginia, and Wisconsin and identified 16 unique haplotypes. Analyses of the sequence data revealed very little genetic differentiation among isolates and no clear evidence of phylogenetic structure, although there was evidence for some genetic differentiation between the Massachusetts and Texas populations. These results suggest that sexual mating (macrocyst formation) is not likely to correlate with either genetic or geographical distance. To test this prediction, we performed 108 mating experiments and found no association between mating probability and genetic or geographical distance. Conclusions: $D. giganteum$ isolates from across North America display little genetic variation, phylogeographic structure, and genetic differentiation among populations relative to the cryptic species observed within $D. purpureum$. Furthermore, variation that does exist does not predict the probability of mating among clones. These results have important implications for our understanding of speciation and social evolution in microbes.Other Research Uni

DNA methylation is widespread across social Hymenoptera

SummaryGenomic imprinting is an epigenetic phenomenon by which the expression of a gene is influenced by the parent from which it is inherited. The evolutionary causes of imprinting are mysterious but it is likely to represent a form of within-genome conflict [1]. For instance, alleles inherited from the father and the mother will be in conflict over treatment of relatives to which they are differently related. In this context, natural selection may favor alleles with effects that differ depending on the allele's parental origin [1,2]. This ‘kinship theory of imprinting’ has been developed and tested largely in the context of parental provisioning of offspring [1,2]. Given their haplodiploid genetic system and interspecific variation in social traits, the Hymenoptera (ants, bees, and wasps) provide a large variety of novel contexts in which to examine this theory [2]. However, aside from evidence that imprinting determines sex in the parasitic wasp Nasonia vitripennis [3], and a QTL that appears to be paternally inherited in the honeybee [4], nothing is known about imprinting in this group of animals. Here we provide evidence that CpG methylation, a hallmark of imprinting, is ubiquitously present in social insects but the proportion of methylated sites varies substantially among species and developmental stages

Phylogeography and sexual macrocyst formation in the social amoeba Dictyostelium giganteum

<p>Abstract</p> <p>Background</p> <p>Microorganisms are ubiquitous, yet we are only beginning to understand their diversity and population structure. Social amoebae (Dictyostelia) are a diverse group of unicellular eukaryotic microbes that display a unique social behaviour upon starvation in which cells congregate and then some die to help others survive and disperse. The genetic relationships among co-occurring cells have a major influence on the evolution of social traits and recent population genetic analysis found extensive genetic variation and possible cryptic speciation in one dictyostelid species (<it>Dictyostelium purpureum</it>). To further characterize the interplay among genetic variation, species boundaries, social behaviour, and reproductive isolation in the Dictyostelia, we conducted phylogenetic analyses and mating experiments with the geographically widespread social amoeba <it>Dictyostelium giganteum</it>.</p> <p>Results</p> <p>We sequenced approximately 4,000 basepairs of the nuclear ribosomal DNA from 24 isolates collected from Texas, Michigan, Massachusetts, Virginia, and Wisconsin and identified 16 unique haplotypes. Analyses of the sequence data revealed very little genetic differentiation among isolates and no clear evidence of phylogenetic structure, although there was evidence for some genetic differentiation between the Massachusetts and Texas populations. These results suggest that sexual mating (macrocyst formation) is not likely to correlate with either genetic or geographical distance. To test this prediction, we performed 108 mating experiments and found no association between mating probability and genetic or geographical distance.</p> <p>Conclusions</p> <p><it>D. giganteum </it>isolates from across North America display little genetic variation, phylogeographic structure, and genetic differentiation among populations relative to the cryptic species observed within <it>D. purpureum</it>. Furthermore, variation that does exist does not predict the probability of mating among clones. These results have important implications for our understanding of speciation and social evolution in microbes.</p