Divergence with gene flow across a speciation continuum of Heliconius butterflies

BACKGROUND: A key to understanding the origins of species is determining the evolutionary processes that drive the patterns of genomic divergence during speciation. New genomic technologies enable the study of high-resolution genomic patterns of divergence across natural speciation continua, where taxa pairs with different levels of reproductive isolation can be used as proxies for different stages of speciation. Empirical studies of these speciation continua can provide valuable insights into how genomes diverge during speciation. METHODS: We examine variation across a handful of genomic regions in parapatric and allopatric populations of Heliconius butterflies with varying levels of reproductive isolation. Genome sequences were mapped to 2.2-Mb of the H. erato genome, including 1-Mb across the red color pattern locus and multiple regions unlinked to color pattern variation. RESULTS: Phylogenetic analyses reveal a speciation continuum of pairs of hybridizing races and incipient species in the Heliconius erato clade. Comparisons of hybridizing pairs of divergently colored races and incipient species reveal that genomic divergence increases with ecological and reproductive isolation, not only across the locus responsible for adaptive variation in red wing coloration, but also at genomic regions unlinked to color pattern. DISCUSSION: We observe high levels of divergence between the incipient species H. erato and H. himera, suggesting that divergence may accumulate early in the speciation process. Comparisons of genomic divergence between the incipient species and allopatric races suggest that limited gene flow cannot account for the observed high levels of divergence between the incipient species. CONCLUSIONS: Our results provide a reconstruction of the speciation continuum across the H. erato clade and provide insights into the processes that drive genomic divergence during speciation, establishing the H. erato clade as a powerful framework for the study of speciation.This work was funded by the following awards: Hanne and Torkel Weis-Fogh Fund (sample collection, awarded to Nicola Nadeau and Richard Merrill); CNRS Nouraugues (BAC); NSF DEB-1257839 (BAC), DEB-1257689 (WOM), DEB- 1027019 (WOM); and the Smithsonian Institution

Q&A with Jessica Counterman (MFA Painting)

https://egrove.olemiss.edu/art_qa/1038/thumbnail.jp

Assessing Visual Preference among Fourth Grade Students for Habitat Components on Educational Green Roofs in Starkville, Mississippi

As urbanization grows wildlife habitat is displaced and fragmented. Vegetative roofs offer an innovative alternative to provide animal food and habitat in urban environments. This research study investigates how wildlife needs in a green roof ecosystem are interpreted through children’s visual perception. A visual preference survey was administered to fourth-grade students in Starkville, Mississippi which offered paired photographs displaying basic vertebrate and invertebrate needs. The responses from 85 students (n=85) were compared to identify preferences for legible habitat components. The results of this survey showed that fourth-grade students could readily identify the basic habitat needs for birds but were less able to with insects. Students were intrigued with utilizing a green roof for learning and play. Green roofs have potential to be designed as innovative teaching tools to enhance science education in K-12 schools

Deliberate self-harm in clinical and non-clinical populations

Approximately 4% of the general population and 14% of college students have engaged or currently engage in deliberate self-harm. The purpose of the Literature Review is to assess similarities and differences of demographic information, gender, age, frequency, prevalence rates, methods, and reasons of self-harm in both clinical and non-clinical samples. Definitions and alternate names of self-harm were presented, common misconceptions regarding gender were discussed, and frequency and prevalence rates in clinical and non-clinical samples were compared

Highly conserved gene order and numerous novel repetitive elements in genomic regions linked to wing pattern variation in Heliconius butterflies

This is the final version of the article. Available from the publisher via the DOI in this record.BACKGROUND: With over 20 parapatric races differing in their warningly colored wing patterns, the butterfly Heliconius erato provides a fascinating example of an adaptive radiation. Together with matching races of its co-mimic Heliconius melpomene, H. erato also represents a textbook case of Müllerian mimicry, a phenomenon where common warning signals are shared amongst noxious organisms. It is of great interest to identify the specific genes that control the mimetic wing patterns of H. erato and H. melpomene. To this end we have undertaken comparative mapping and targeted genomic sequencing in both species. This paper reports on a comparative analysis of genomic sequences linked to color pattern mimicry genes in Heliconius. RESULTS: Scoring AFLP polymorphisms in H. erato broods allowed us to survey loci at approximately 362 kb intervals across the genome. With this strategy we were able to identify markers tightly linked to two color pattern genes: D and Cr, which were then used to screen H. erato BAC libraries in order to identify clones for sequencing. Gene density across 600 kb of BAC sequences appeared relatively low, although the number of predicted open reading frames was typical for an insect. We focused analyses on the D- and Cr-linked H. erato BAC sequences and on the Yb-linked H. melpomene BAC sequence. A comparative analysis between homologous regions of H. erato (Cr-linked BAC) and H. melpomene (Yb-linked BAC) revealed high levels of sequence conservation and microsynteny between the two species. We found that repeated elements constitute 26% and 20% of BAC sequences from H. erato and H. melpomene respectively. The majority of these repetitive sequences appear to be novel, as they showed no significant similarity to any other available insect sequences. We also observed signs of fine scale conservation of gene order between Heliconius and the moth Bombyx mori, suggesting that lepidopteran genome architecture may be conserved over very long evolutionary time scales. CONCLUSION: Here we have demonstrated the tractability of progressing from a genetic linkage map to genomic sequence data in Heliconius butterflies. We have also shown that fine-scale gene order is highly conserved between distantly related Heliconius species, and also between Heliconius and B. mori. Together, these findings suggest that genome structure in macrolepidoptera might be very conserved, and show that mapping and positional cloning efforts in different lepidopteran species can be reciprocally informative.The work was funded by U.S. National Science Foundation grants IOB 0344705 and DEB 0715096 to WOM. The H. erato BAC library was constructed by C. Wu, H. Zhang (TAMU), and M. R. Goldsmith (URI) under NSF Grant IBN-0208388. In addition, the Computational Biology Service Unit at Cornell University, which is partially funded by Microsoft Corporation, provided bioinformatics support for our analysis of genomic repeat structure. AFLP analysis and sequencing of PCR products was carried out at the Sequencing and Genotyping Center at the University of Puerto RicoRio Piedras. We thank Nicola Flanagan, Alexandra Tobler, Karla Maldonado, Jenny Acevedo Gonzales, Hector Alejandro Merchan, Yhadi Cotto, Kelitt Santiago and Felix Araujo Perez for help in rearing and maintaining butterfly stocks. Finally, a special thanks to Daniel P. Lindstrom for his support and helpful suggestions during manuscript preparation

Molecular mechanisms of kynurenine-mediated lifespan regulation in yeast

The kynurenine pathway is a highly conserved pathway that acts as the primary pathway for tryptophan catabolism and has been found to be involved in lifespan regulation across many diverse organisms. Caloric restriction (CR) is the only known dietary intervention to date that both increases the mean lifespan and the health span of multiple organisms, although the molecular mechanisms of these effects are not fully understood. There are known and sometimes contradictory relationships between the kynurenine pathway activity and the life- extending effect of CR but the crosstalk between the two is not well characterized. Understanding these relationships could lead to interventions by which both lifespan and health span can be modulated. Our findings aim to identify genetic components of the kynurenine pathway that affect the lifespan extending effects of caloric restriction. We applied an RNAseq focused approach for identifying molecular changes mediated by kynurenine pathway deficiency under control and CR conditions and further assayed several phenotypic outcomes. As a result, we identified genes and pathways regulated by kynurenine pathways activity and found that decreased tryptophan catabolism is required or CR-mediated lifespan extension. Further research is needed to elucidate the lifespan altering effects of Kynurenine pathway activity in a dose dependent manner as it relates to the beneficial effects of CR

Genomic architecture of adaptive color pattern divergence and convergence in Heliconius butterflies

Identifying the genetic changes driving adaptive variation in natural populations is key to understanding the origins of biodiversity. The mosaic of mimetic wing patterns in Heliconius butterflies makes an excellent system for exploring adaptive variation using next-generation sequencing. In this study, we use a combination of techniques to annotate the genomic interval modulating red color pattern variation, identify a narrow region responsible for adaptive divergence and convergence in Heliconius wing color patterns, and explore the evolutionary history of these adaptive alleles. We use whole genome resequencing from four hybrid zones between divergent color pattern races of Heliconius erato and two hybrid zones of the co-mimic Heliconius melpomene to examine genetic variation across 2.2 Mb of a partial reference sequence. In the intergenic region near optix, the gene previously shown to be responsible for the complex red pattern variation in Heliconius, population genetic analyses identify a shared 65-kb region of divergence that includes several sites perfectly associated with phenotype within each species. This region likely contains multiple cis-regulatory elements that control discrete expression domains of optix. The parallel signatures of genetic differentiation in H. erato and H. melpomene support a shared genetic architecture between the two distantly related co-mimics; however, phylogenetic analysis suggests mimetic patterns in each species evolved independently. Using a combination of next-generation sequencing analyses, we have refined our understanding of the genetic architecture of wing pattern variation in Heliconius and gained important insights into the evolution of novel adaptive phenotypes in natural populations

Phylogenetic Codivergence Supports Coevolution of Mimetic Heliconius Butterflies

The unpalatable and warning-patterned butterflies _Heliconius erato_ and _Heliconius melpomene_ provide the best studied example of mutualistic Müllerian mimicry, thought – but rarely demonstrated – to promote coevolution. Some of the strongest available evidence for coevolution comes from phylogenetic codivergence, the parallel divergence of ecologically associated lineages. Early evolutionary reconstructions suggested codivergence between mimetic populations of _H. erato_ and _H. melpomene_, and this was initially hailed as the most striking known case of coevolution. However, subsequent molecular phylogenetic analyses found discrepancies in phylogenetic branching patterns and timing (topological and temporal incongruence) that argued against codivergence. We present the first explicit cophylogenetic test of codivergence between mimetic populations of _H. erato_ and _H. melpomene_, and re-examine the timing of these radiations. We find statistically significant topological congruence between multilocus coalescent population phylogenies of _H. erato_ and _H. melpomene_, supporting repeated codivergence of mimetic populations. Divergence time estimates, based on a Bayesian coalescent model, suggest that the evolutionary radiations of _H. erato_ and _H. melpomene_ occurred over the same time period, and are compatible with a series of temporally congruent codivergence events. This evidence supports a history of reciprocal coevolution between Müllerian co-mimics characterised by phylogenetic codivergence and parallel phenotypic change

Course Placement, Course Modality, and Student Success: Developmental Mathematics at a Public Two-Year College in the Northeast

Changing how we present information to students has been standard discourse from as early as the 5th century BC, when Quintilian stated that teachers needed to reach students with different learning styles at different points in their education (Corno, 2008). There are varied methods for reaching students with learning disabilities, language or cultural differences, and content-related struggles, but no singular method has proven to be the “best” choice for all learners. This research study examined archival data of developmental mathematics students from fall 2015 through spring 2019 at Northampton Community College (N.C.C.). Purpose The purposes of this journal-ready dissertation were to look for differences in student success and persistence in developmental mathematics based on three factors: placement, students’ perceptions of their motivation and anxiety, and the course modality they chose. The first purpose was to analyze the success and persistence of students in mathematics, based on the college’s placement policy of utilizing high school transcripts and ACCUPLACER exam. The second purpose was to determine if developmental students’ perceptions of their motivation and anxiety levels impacted their final course grade or persistence in mathematics at the college. Finally, the third purpose was to examine the differences between final exam grades, final course grades, and persistence to the next mathematics courses at the college, based on developmental mathematics course modality. The first and third research study involved an analysis of four years of data from a suburban community college in Northeastern Pennsylvania. The second study involved the survey of developmental mathematics students in the spring of 2019. Method This study was a causal-comparative research design using archival data from Northampton Community College Institutional Review Board for fall 2015 through spring 2019 school years. Statistical data were analyzed to determine whether differences existed in final exams, final course grades, persistence in mathematics, and motivation and anxiety levels for students enrolled in developmental mathematics in either emporium, face-to-face, or online courses during this timeframe. Findings In the first study, chi-square analysis revealed that placement by high school transcripts appeared to result in higher success and persistence in mathematics for students. The second study examined how students’ perceptions of their intrinsic and extrinsic motivation and anxiety levels affected their course grades in these courses, based on their modality using MANOVA and t-test analysis. Regardless of student success or course modality, students who responded to the survey were more worried and extrinsically motivated than had negative affection reactions (NAR) or were intrinsically motivated. In the third study, chi-square analysis revealed that, overall, students in emporium and face-to-face courses performed equally as well, but online students struggled more with final course grades and persistence in mathematics at the college. The conclusion of this journal-style dissertation includes connections with literature and theoretical frameworks and suggestions for practice and future research