Luana Maroja
Williams College, Biology, Faculty Member
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<p>Colored regions represent focus species/race distributions (each colored area has both <i>H. erato</i> and the co-mimetic <i>H. melpomene</i>), light grey areas represent areas where <i>H.... more
<p>Colored regions represent focus species/race distributions (each colored area has both <i>H. erato</i> and the co-mimetic <i>H. melpomene</i>), light grey areas represent areas where <i>H. melpomene</i> and <i>H. erato</i> overlap and dark grey areas represent areas where only <i>H. erato</i> occurs. Map based on <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0048627#pone.0048627-Brown2" target="_blank">[37]</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0048627#pone.0048627-Rosser1" target="_blank">[38]</a>.</p
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Hmel1-2_haploid and pacbio_haploid merged by HaploMerge
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Hmel1-2 genome collapsed by HaploMerge
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SQLite3 database containing marker information for linkage map (see README.txt for table descriptions
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Variant calls for Heliconius melpomene mapping cross aligned to Hmel1-1 primary scaffolds (Hmel1-1_primaryScaffolds.fa
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Variant calls for Heliconius melpomene mapping cross aligned to Hmel1-1 haplotype scaffolds (Hmel_haplotype_scaffolds.fas
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A snapshot of the bespoke code written to reassemble the genome, available from https://github.com/johnomics/Heliconius_melpomene_version_2, commit f826fd1 from Dec 10, 201
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Variant calls for Eueides isabella cross aligned to Hmel2.f
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FALCON PacBio assembly collapsed by HaploMerge
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Initial assembly of PacBio reads with FALCO
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Background The hybridizing field crickets, Gryllus firmus and Gryllus pennsylvanicus have several barriers that prevent gene flow between species. The behavioral pre-zygotic mating barrier, where males court conspecifics more intensely... more
Background The hybridizing field crickets, Gryllus firmus and Gryllus pennsylvanicus have several barriers that prevent gene flow between species. The behavioral pre-zygotic mating barrier, where males court conspecifics more intensely than heterospecifics, is important because by acting earlier in the life cycle it has the potential to prevent a larger fraction of hybridization. The mechanism behind such male mate preference is unknown. Here we investigate if the female cuticular hydrocarbon (CHC) profile could be the signal behind male courtship. Results While males of the two species display nearly identical CHC profiles, females have different, albeit overlapping profiles and some females (between 15 and 45%) of both species display a male-like profile distinct from profiles of typical females. We classified CHC females profile into three categories: G. firmus-like (F; including mainly G. firmus females), G. pennsylvanicus-like (P; including mainly G. pennsylvanicus females), an...
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Research Interests: Pigmentation, Molecular Evolution, Biology, Multidisciplinary, Nature, and 9 moreButterflies, Color, Female, Animals, Male, Crypsis, Mimicry, Phenotype, and Aposematism
Phylogenetic reconstruction, divergence times, and population genetics are critical concepts for a complete understanding of evolution. Unfortunately, students generally lack “tree-thinking” skills and are often unmotivated to explore... more
Phylogenetic reconstruction, divergence times, and population genetics are critical concepts for a complete understanding of evolution. Unfortunately, students generally lack “tree-thinking” skills and are often unmotivated to explore these concepts using typical classroom exercises that feature taxa unknown to students or simulated datasets. To generate greater student interest, we have developed an affordable practical lab ($16 dollars per student) where students extract and sequence their own mtDNA and use it for exercises involving phylogenetic reconstruction (placement of own DNA into the world tree), divergence (speciation) time (comparing current student population with chimps, gorillas, and Neanderthal), and population genetics (demographic change calculation based on student’s sample). In contrast to traditional labs, we found that students were highly motivated and enthusiastic throughout the four-week activity. Students had a 100% rate of success in obtaining DNA sequence...
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The rapid evolution of sexual isolation in sympatry has long been associated with reinforcement (i.e., selection to avoid maladaptive hybridization). However, there are many species pairs in sympatry that have evolved rapid sexual... more
The rapid evolution of sexual isolation in sympatry has long been associated with reinforcement (i.e., selection to avoid maladaptive hybridization). However, there are many species pairs in sympatry that have evolved rapid sexual isolation without known costs to hybridization. A major unresolved question is what evolutionary processes are involved in driving rapid speciation in such cases. Here, we focus on one such system; thespecies complex, which is composed of three partially sympatric and interfertile semispecies: WN, EA, and EB. To study speciation in this species complex, we assayed sexual and genomic isolation within and between these semispecies in both sympatric and allopatric populations. First, we found no evidence of reproductive character displacement (RCD) in sympatric zones compared to distant allopatry. Instead, semispecies were virtually completely sexually isolated from each other across their entire ranges. Moreover, using spatial approaches and coalescent demog...
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Inositol 1,4,5-trisphosphate (IP3) regulates a host of biological processes from egg activation to cell death. When IP3-specific receptors (IP3Rs) bind to IP3, they release calcium from the ER into the cytoplasm, triggering a variety of... more
Inositol 1,4,5-trisphosphate (IP3) regulates a host of biological processes from egg activation to cell death. When IP3-specific receptors (IP3Rs) bind to IP3, they release calcium from the ER into the cytoplasm, triggering a variety of cell type- and developmental stage-specific responses. Alternatively, inositol polyphosphate kinases can phosphorylate IP3; this limits IP3R activation by reducing IP3 levels, and also generates new signaling molecules altogether. These divergent pathways draw from the same IP3 pool yet cause very different cellular responses. Therefore, controlling the relative rates of IP3R activation versus phosphorylation of IP3 is essential for proper cell functioning. Establishing a model system that sensitively reports the net output of IP3 signaling is crucial for identifying the controlling genes. Here we report that mutant alleles of wavy (wy), a classic locus of the fruit fly Drosophila melanogaster, map to IP3 3-kinase 2 (IP3K2), a member of the inositol ...
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Characterizing the extent of genomic differentiation between recently diverged lineages provides an important context for understanding the early stages of speciation. When such lineages form discrete hybrid zones, patterns of... more
Characterizing the extent of genomic differentiation between recently diverged lineages provides an important context for understanding the early stages of speciation. When such lineages form discrete hybrid zones, patterns of differential introgression allow direct estimates of which genome regions are likely involved in speciation and local adaptation. Here we use a backcross experimental design to construct a genetic linkage map for the field crickets Gryllus firmus and Gryllus pennsylvanicus, which interact in a well-characterized hybrid zone in eastern North America. We demonstrate that loci with major allele frequency differences between allopatric populations are not randomly distributed across the genome. Instead, most are either X-linked or map to a few small autosomal regions. Furthermore, the subset of those highly differentiated markers that exhibit restricted introgression across the cricket hybrid zone are also concentrated on the X chromosome (39 of 50 loci) and in a ...
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Research Interests: Evolutionary Biology, Pigmentation, Genomics, Gene Flow, Molecular Evolution, and 15 moreBiology, Multidisciplinary, Nature, Butterflies, Phylogeny, Animals, Molecular Phylogenetics and Evolution, Mimicry, Molecular Mimicry, Butterfly, Species Specificity, Bombyx mori, Synteny, Wing, and Molecular Sequence Data
Seven microsatellite loci were used to investigate the genetic variability and structure of six mainland and two island populations of the Neotropical water rat Nectomys squamipes, a South American semi-aquatic rodent species with a wide... more
Seven microsatellite loci were used to investigate the genetic variability and structure of six mainland and two island populations of the Neotropical water rat Nectomys squamipes, a South American semi-aquatic rodent species with a wide distribution. High levels of variability were found within mainland populations while island populations were less variable but the more differentiated in respect to allele number and frequency. The time of biological divergence between mainland and island populations coincided with geological data. A significant geographic structure was found in mainland populations ( = 0.099; = 0.086) although the degree of differentiation was relatively low in respect to the distance between surveyed localities (24 to 740 km). Genetic and geographic distances were not positively correlated as previously found with random amplified polymorphic DNA (RAPD) markers. Significant but low genetic differentiation in the mainland and lack of isolation by distance can be e...
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Two Atlantic Forests and two Cerrado areas in Brazil were sampled for non-flying small mammal fauna. In each biome one area with altered and another with almost unaltered vegetation (national parks), were chosen to investigate these... more
Two Atlantic Forests and two Cerrado areas in Brazil were sampled for non-flying small mammal fauna. In each biome one area with altered and another with almost unaltered vegetation (national parks), were chosen to investigate these fauna. Species richness of Atlantic Forest and Cerrado was comparable in the conserved as well as in the altered areas. Data suggested that species could be divided into different ecological categories according to distribution, use of altered and/or relatively unaltered vegetation and habitat specificity. Within these ecological categories some species are appropriate indicators for monitoring environmental quality and degradation. Useful guidelines for wildlife management planning, including selecting areas for conservation units and their better boundary delimitation can ensue.
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• Twelve microsatellite markers were developed for Primula mistassinica, a distylous, diploid arctic-alpine plant. The markers will be used to investigate the landscape genetics of a disjunct population on Isle Royale, Michigan, and the... more
• Twelve microsatellite markers were developed for Primula mistassinica, a distylous, diploid arctic-alpine plant. The markers will be used to investigate the landscape genetics of a disjunct population on Isle Royale, Michigan, and the phylogeographic patterns of the species. • We used Roche/454 high-throughput technology to sequence microsatellite-enriched regions in the P. mistassinica genome. We developed 12 polymorphic microsatellite primer sets. These loci contained di-, tri-, and tetranucleotide repeats with two to nine alleles per locus when assessed in 23 individuals. • Understanding the historical movements of P. mistassinica will provide insight to the survival prospects of current Arctic plant populations, which face the pressures of global, anthropogenic climate change.