Search bioRxiv⌕ Search

Biology subjects

Matute, D. R.

Publications and source records attributed to Matute, D. R..

At least 37 records · Page 2Linked to original sources

Ancestral neural circuits potentiate the origin of a female sexual behavior

Courtship interactions are remarkably diverse in form and complexity among species. How neural circuits evolve to encode new behaviors that are functionally integrated into these dynamic social interactions is unknown. Here we report a recently originated female sexual behavior in the island endemic Drosophila species D. santomea, where females signal receptivity to male courtship songs by spreading their wings, which in turn promotes prolonged songs in courting males. Copulation success depends on this female signal and correlates with males ability to adjust his singing in such a social feedback loop. Functional comparison of sexual circuitry across species suggests that a pair of descending neurons, which integrates male song stimuli and female internal state to control a conserved female abdominal behavior, drives wing spreading in D. santomea. This co-option occurred through the refinement of a pre-existing, plastic circuit that can be optogenetically activated in an outgroup species. Combined, our results show that the ancestral potential of a socially-tuned key circuit node to engage the wing motor program facilitates the expression of a new female behavior in appropriate sensory and motivational contexts. More broadly, our work provides insights into the evolution of social behaviors, particularly female behaviors, and the underlying neural mechanisms.

evolutionary biology↗

The spread of Aedes albopictus in the islands of Sao Tome and Principe

The mosquito Aedes albopictus is a vector species of Dengue, yellow fever, and Zika among other diseases. The species originated in Southeast Asia and has spread widely and rapidly in the last century. The species has been reported in localities from the Gulf of Guinea since the early 2000s, but systematic sampling has been scant. We sampled Ae. albopictus between 2013 and 2023 across the altitudinal gradient in Sao Tome and found that the species was present in all sampled years at altitudes up to 680 meters. We also find some evidence of increases in proportional representation compared to Ae. aegypti over time. We report the presence of the species in Principe for the first time, suggesting that the range of Ae. albopictus is larger than previously thought. Finally, we use bioclimatic niche modeling to infer the potential range of Ae. albopictus and infer that the species has the potential to spread across a large portion of Sao Tome and Principe. Our results suggest that Ae. albopictus has established itself as a resident species of the islands of the Gulf of Guinea and should be incorporated into the list of potential vectors that need to be surveyed and controlled.

zoology↗

Aedes albopictus is present in the lowlands of southern Zambia

Identifying the current geographic range of disease vectors is a critical first step towards determining effective mechanisms for controlling and potentially eradicating them. This is particularly true given that historical vector ranges may expand due to changing climates and human activity. The Aedes subgenus Stegomyia contains over 100 species, and among them, Ae. aegypti and Ae. albopictus mosquitoes represent the largest concern for public health, spreading dengue, chikungunya, and Zika viruses. While Ae. aegypti has been observed in the country of Zambia for decades, Ae. albopictus has not. In 2015 we sampled four urban and two rural areas in Zambia for Aedes species. Using DNA barcoding, we confirmed the presence of immature and adult Ae. albopictus at two rural sites: Siavonga and Livingstone. These genotypes seem most closely related to specimens previously collected in Mozambique based on CO1 sequence from mtDNA. We resampled Siavonga and Livingstone sites in 2019, again observing immature and adult Ae. albopictus at both sites. Relative Ae. albopictus frequencies were similar between sites, with the exception of immature life stages, which were higher in Siavonga than in Livingstone in 2019. While Ae. albopictus frequencies did not vary through time in Livingstone, both immature and adult frequencies increased through time in Siavonga. This report serves to document the presence of Ae. albopictus in Zambia, which will contribute to the process of determining the potential public health implications of this disease vector in Central Africa.

zoology↗

Isotopic niches do not follow the expectations of niche conservatism in the bird genus Cinclodes

Phenotypic traits are expected to be more similar among closely related species than among species that diverged long ago (all else being equal). This pattern, known as phylogenetic niche conservatism, also applies to traits that are important to determine the niche of species. To test this hypothesis on ecological niches, we analyzed isotopic data from 254 museum study skins from 12 of the 16 species of the bird genus Cinclodes and measured stable isotope ratios for four different elements: Carbon, Nitrogen, Hydrogen and Oxygen. We find that all traits, measured individually, or as a composite measurement, lack any phylogenetic signal, which in turn suggests a high level of lability in ecological niches. We compared these metrics to the measurements of morphological traits in the same genus and found that isotopic niches are uniquely evolutionarily labile compared to other traits. Our results suggest that, in Cinclodes, the realized niche evolves much faster than expected by the constraints of phylogenetic history and poses the question of whether this is a general pattern across the tree of life.

evolutionary biology↗

The fitness of an introgressing haplotype

The genomic era has made clear that introgression, or the movement of genetic material between species, is a common feature of evolution. Examples of both adaptive and deleterious introgression exist in a variety of systems. What is unclear is how the fitness of an introgressing haplotype changes as species diverge, or as the size of the introgressing haplotype changes. In a simple model, we show that early in the process of divergence, introgression of large haplotypes can be favored more than introgression of individual alleles. The key insight is that alleles from a shared genetic background are likely to have positive epistatic interactions, increasing the fitness of a larger introgressing block. The buildup of incompatibilities between diverging species in the form of deleterious epistasis eventually favors the introgression of small haplotypes as the number of diverged alleles increases, and eventually even single alleles with positive direct effects can be selected against. This model is consistent with observations of a positive relationship between recombination rate and introgression frequency across the genome, however it generates several novel predictions. First, the model suggests that the relationship between recombination rate and introgression may not exist, or may be negative, in recently diverged species pairs. Furthermore, the model suggests that introgression that replaces existing derived variation will always be more deleterious than introgression at sites carrying ancestral variants. These predictions are tested in an example of introgression in D. melanogaster, with some support for both.

evolutionary biology↗

Strong positive selection in Aedes aegypti and the rapid evolution of insecticide resistance

Aedes aegypti vectors the pathogens that cause dengue, yellow fever, Zika virus, and chikungunya, and is a serious threat to public health in tropical regions. Decades of work has illuminated many aspects of Ae. aegyptis biology and global population structure, and has identified insecticide resistance genes; however, the size and repetitive nature of the Ae. aegypti genome have limited our ability to detect positive selection in this mosquito. Combining new whole genome sequences from Colombia with publicly available data from Africa and the Americas, we identify multiple strong candidate selective sweeps in Ae. aegypti, many of which overlap genes linked to or implicated in insecticide resistance. We examine the voltage-gated sodium channel gene in three American cohorts, and find evidence for successive selective sweeps in Colombia. The most recent sweep encompasses an intermediate-frequency haplotype containing four candidate insecticide resistance mutations that are in near-perfect linkage disequilibrium with one another in the Colombian sample. We hypothesize that this haplotype may continue to rapidly increase in frequency and perhaps spread geographically in the coming years. These results extend our knowledge of how insecticide resistance has evolved in this species, and add to a growing body of evidence suggesting Ae. aegypti has an extensive genomic capacity to rapidly adapt to insecticide-based vector control.

genomics↗

Diversity of cave Phlebotomines (Diptera: Psychodidae) from a Colombian cave

Sandflies are vector species of Leishmania, among many other pathogens, with a global distribution and a variety of ecological niches. Previous samplings have found that karstic formations (i.e., caves and folds formed by the erosion of limestone) serve as a natural habitat to sandfly species. The majority of samplings of cave sandfly diversity have occurred in Brazil and to date none have studied the species composition in a cave in the Northern Andes. We collected sandflies in the Cave "Los Guacharos", in the state of Antioquia, Colombia. The sampling was carried out during two consecutive nights in September 2019. CDC-type light traps were installed inside the cavern and in other surrounding karst systems (caves and folds). In total, we identified 18 species of sandfly from the cave and surrounding karst systems, including three new records for Colombia (Bichromomyia olmeca nociva, Brumptomyia brumpti, and Warileya leponti), and provide the first karstic reports for four other species (Lutzomyia gomezi, Lutzomyia hartmanni, Pintomyia ovallesi, and Psychodopygus panamensis). We then used the results of our survey and published literature to test two hypotheses. First, that sandfly diversity in Neotropical caves is richest nearer to the equator and second that there is a phylogenetic signal of karstic habitat use in sandflies. Counter to our predictions, we found no evidence that diversity follows a latitudinal gradient. Further, we find no evidence of a phylogenetic signal of karstic habitat use, instead finding that the use of caves likely evolved multiple times across several genera. Our results highlight the importance of a wide sampling to understand the natural habitat of sandflies and other disease vectors.

zoology↗

Climatic niche conservatism in a clade of disease vectors (Diptera: Phlebotominae)

Sandflies of the family Psychodidae show notable diversity in both disease vector status and climatic niche. Some species (in the subfamily Phlebotominae) transmit Leishmania parasites, responsible for the disease leishmaniasis. Other Psychodidae species do not. Psychodid species ranges can be solely tropical, confined to the temperate zones, or span both. Studying the relationship between the evolution of disease vector status and that of climatic niche affords an understanding not only of the climate conditions associated with the presence and species richness of Leishmania vectors, but also allows the study of the extent to which psychodid flies climatic niches are conserved, in a context with implications for global human health. We obtained observation site data, and associated climate data, for 223 psychodid species to understand which aspects of climate most closely predict distribution. Temperature and seasonality are strong determinants of species occurrence within the clade. We built a mitochondrial DNA phylogeny of Psychodidae, and found a positive relationship between pairwise genetic distance and climate niche differentiation, which indicates strong niche conservatism. This result is also supported by strong phylogenetic signals of metrics of climate differentiation. Finally, we used ancestral trait reconstruction to infer the tropicality (i.e., proportion of latitudinal range in the tropics minus the proportion of the latitudinal range in temperate areas) of ancestral species, and counted transitions to and from tropicality states, finding that tropical and temperate species respectively produced almost entirely tropical and temperate descendant species, a result consistent for vector and non-vector species. Taken together, these results imply that while vectors of Leishmania can survive in a variety of climates, their climate niches are strongly predicted by phylogeny.

evolutionary biology↗

Gap genes are involved in inviability in hybrids between Drosophila melanogaster and D. santomea

Evolved changes within species can lead to the loss of viability in hybrids. Inviability is also a convenient phenotype to genetically map and validate functionally divergent genes and pathways differentiating closely related species. Here, I identify the Drosophila melanogaster form of the highly conserved essential gap gene giant (gt) as a key genetic determinant of inviability in hybrids with D. santomea. The presence of this allele is sufficient and necessary to cause a prevalent abdominal ablation in the developing hybrid embryo. Further genetic analysis indicates that tailless (tll), another gap gene, is also involved in the hybrid defects. giant and tll are both members of the gap gene network of transcription factors that participate in establishing anterior-posterior specification of the dipteran embryo, a highly conserved developmental process. I found no evidence for positive selection in either of the two genes. Genes whose outputs in this process are functionally conserved nevertheless evolve over short timescales to cause inviability in hybrids. SIGNIFICANCE STATEMENTHybrid organisms--which have parents from different species--are usually less healthy than pure-species organisms. Hybrid inviability is an extreme example of this phenomenon. Defects result from incompatibilities between genes that have diverged in the parental species. In this piece, I dissect the genetic basis of hybrid inviability between two species of Drosophila: D. melanogaster and D. santomea. I identified two genes, gt and tll responsible for the inviability in these hybrids. The two genes belong to the gap gene network, a highly conserved pathway that is in charge of establishing embryonic polarity in insects. These results show that developmentally important genes might evolve sufficiently fast to cause hybrid inviability in species that still can interbreed.

evolutionary biology↗

The evolutionary trajectory of drosophilid walking

Neural circuits must both execute the behavioral repertoire of individuals and account for behavioral variation across species. Understanding how this variation emerges over evolutionary time requires large-scale phylogenetic comparisons of behavioral repertoires. Here, we describe the evolution of walking in fruit flies by capturing high-resolution, unconstrained movement from 13 species and 15 strains of drosophilids. We find that walking can be captured in a universal behavior space, the structure of which is evolutionarily conserved. However, the occurrence of, and transitions between, specific movements have evolved rapidly, resulting in repeated convergent evolution in the temporal structure of locomotion. Moreover, a meta-analysis demonstrates that many behaviors evolve more rapidly than other traits. Thus, the architecture and physiology of locomotor circuits can both execute precise individual movements in one species and simultaneously support rapid evolutionary changes in the temporal ordering of these modular elements across clades.

animal behavior and cognition↗

Rapid evolution of the functionally conserved gap gene giant in Drosophila

Developmental processes in multicellular organisms, and the outcomes they produce, are often evolutionarily conserved. Yet phylogenetic conservation of developmental outcomes is not reflected in functional preservation of the genes regulating these processes, a phenomenon referred to as developmental system drift (1, 2). Little is known about the evolutionary forces producing change in the molecular details of regulatory genes and their networks while preserving development outcomes. Here we address this void in knowledge by systematically swapping the Drosophila melanogaster coding and noncoding regions of the essential gap gene, giant, a key regulator of embryonic pattern formation, with orthologous sequences drawn from both closely and distantly related species within the genus. Employing sensitized genetic complementation assays, the loss of a transgenes ability to restore viability occurs across phylogeny at every interspecific level of comparison and includes both coding and noncoding changes. Epistasis is present as well -- both between coding and noncoding sequences and, in a dramatic example of change-of-sign epistasis, between the only two coding substitutions separating two very closely related species. A continuous process of functional divergence hidden under conserved phylotypic developmental outcomes requires reconsideration of the prevailing view that the essential genes in conserved regulatory networks are protected from the driving forces of evolutionary change.

evolutionary biology↗

Population structure and introgression among recently differentiated Drosophila melanogaster populations

Despite a century of genetic analysis, the evolutionary history underlying patterns of exceptional genetic and phenotypic variation in the model organism Drosophila melanogaster remains poorly understood. How genetic and phenotypic variation is partitioned across the range of D. melanogaster, particularly in its putative ancestral range in Subtropical Africa, remains unresolved. Here, we assess patterns of population genetic structure, admixture, mate preference, and genetic incompatibility across a global sample, including 174 new accessions from remote regions within Subtropical Africa. While almost all Out of Africa genomes correspond to a single genetic ancestry, different geographic regions within Africa contain multiple ancestries, with substantial cryptic diversity in Subtropical Africa. Admixture between distinct lineages is prevalent across the range, but admixture rates vary between lineages. Female mate choice within Subtropical Africa is highly polymorphic and behavioral types are not monophyletic. The genetic architecture of mate choice is highly polygenic, including loci associated with neurological development, behavior, olfactory perception, and learning. Finally, we discovered that many segregating putative incompatibilities likely evolved during or after expansion out of Africa. This work contributes to our understanding of the evolutionary history of a key model system, and provides insight into the distribution of polymorphic reproductive barriers.

evolutionary biology↗

15 years of introgression studies: quantifying gene flow across Eukaryotes

With the rise of affordable next generation sequencing technology, introgression -- or the exchange of genetic materials between taxa -- is widely perceived to be a ubiquitous phenomenon in nature. Although this claim is supported by several keystone studies, no thorough assessment on the frequency of introgression in nature has been performed to date. In this manuscript, we aim to address this knowledge gap by providing a meta-analysis of the most comprehensive survey of introgression studies in Eukaryotes to date (724 papers with claims of introgression). We first examined the evidence given to support introgression, and if/how the lines of evidence have changed across time. We then collated a single statistic, Pattersons D, that quantifies the strength of introgression across 123 studies to further assess how taxonomic group, divergence time, and aspects of life history influence introgression. We find three main results. Studies on introgression are much more frequent in plants and mammals than any other taxonomic group. The study of introgression has shifted from a largely qualitative assessment of whether introgression happens, to a focus on when and how much introgression has occurred across taxa. The most often used introgression statistic, Pattersons D, shows several intriguing patterns suggesting introgression reports may be biased by both differences in reporting criteria and sequencing technology, but may also differ across taxonomic systems and throughout the process of speciation. Together, these results suggest the need for a unified approach to quantifying introgression in natural communities, and highlight important areas of future research that can be better assessed once this unified approach is met.

evolutionary biology↗

Reinforcement alone does not explain increased reproductive isolation in sympatry

Understanding mechanisms underlying the origin of species remains a central goal of biology. Comparative studies of reproductive isolation (RI) have observed increased premating, but not postzygotic, RI between sympatric species pairs (Coyne and Orr 1989a, 1997), supporting a significant role for reinforcing natural selection in speciation. Limited data on patterns of RI have inhibited our ability to extend comparative analyses beyond model systems. Here we use an updated Drosophila dataset and measures of postzygotic RI from lepidopterans and toads (Bufo) to assess patterns of postzygotic RI in a comparative framework. Postzygotic RI is higher between sympatric species pairs of all three divergent taxa, including between some recently diverged pairs. Using the updated Drosophila dataset that also includes estimates of premating RI, we demonstrate that comparisons of postzygotic and premating RI depend greatly on divergence time. Both postzygotic and premating RI are strengthened between recently diverged sympatric Drosophila species pairs, as defined by Coyne and Orr (C&O) (Coyne and Orr 1989a) and others (i.e., DNei < 0.5). However, at slightly lower divergence thresholds only premating RI is significantly increased, highlighting the importance of inclusion criteria when performing comparative analyses of RI. While reinforcing natural selection against maladaptive hybridization can strengthen premating RI in sympatry, it is unlikely to contribute significantly to increases in postzygotic RI that we observe. We discuss mechanisms that may combine with reinforcement to generate increased RI in sympatry.

evolutionary biology↗

Widespread introgression across a phylogeny of 155 Drosophila genomes

Genome-scale sequence data have invigorated the study of hybridization and introgression, particularly in animals. However, outside of a few notable cases, we lack systematic tests for introgression at a larger phylogenetic scale across entire clades. Here we leverage 155 genome assemblies, from 149 species, to generate a fossil-calibrated phylogeny and conduct multilocus tests for introgression across nine monophyletic radiations within the genus Drosophila. Using complementary phylogenomic approaches, we identify widespread introgression across the evolutionary history of Drosophila. Mapping gene-tree discordance onto the phylogeny revealed that both ancient and recent introgression has occurred across most of the nine clades that we examined. Our results provide the first evidence of introgression occurring across the evolutionary history of Drosophila and highlight the need to continue to study the evolutionary consequences of hybridization and introgression in this genus and across the Tree of Life.

evolutionary biology↗

Highly contiguous assemblies of 101 drosophilid genomes

Over 100 years of studies in Drosophila melanogaster and related species in the genus Drosophila have facilitated key discoveries in genetics, genomics, and evolution. While high-quality genome assemblies exist for several species in this group, they only encompass a small fraction of the genus. Recent advances in long read sequencing allow high quality genome assemblies for tens or even hundreds of species to be generated. Here, we utilize Oxford Nanopore sequencing to build an open community resource of high-quality assemblies for 101 lines of 95 drosophilid species encompassing 14 species groups and 35 sub-groups with an average contig N50 of 10.5 Mb and greater than 97% BUSCO completeness in 97/101 assemblies. These assemblies, along with detailed wet lab protocol and assembly pipelines, are released as a public resource and will serve as a starting point for addressing broad questions of genetics, ecology, and evolution within this key group.

evolutionary biology↗

Structural characterization and evolutionary analyses of the Coccidioides immitis and Coccidioides posadasii mitochondrial genomes

Fungal mitochondrial genomes encode for genes involved in crucial cellular processes, such as oxidative phosphorylation and mitochondrial translation, and these genes have been used as molecular markers for population genetics studies. Coccidioides immitis and C. posadasii are endemic fungal pathogens that cause coccidioidomycosis in arid regions across both American continents. To date, almost one hundred Coccidioides strains have been sequenced. The focus of these studies has been exclusively to infer patterns of variation of nuclear genomes (nucDNA). However, their mitochondrial genomes (mtDNA) have not been studied. In this report, we describe the assembly and annotation of mitochondrial reference genomes for two representative strains of C. posadasii and C. immitis, as well as assess population variation among 77 published genomes. The circular-mapping mtDNA molecules are 68.2 Kb in C. immitis and 75.1 Kb in C. posadasii. We identified the fourteen mitochondrial protein-coding genes common to most fungal mitochondria, including genes encoding the small and large ribosomal RNAs (rns and rnl), the RNA subunit of RNAse P (rnpB), and 26 tRNAs organized in polycistronic transcription units, which are mostly syntenic across different populations and species of Coccidioides. Both Coccidioides species are characterized by a large number of group I and II introns, harboring twice the number of elements as compared to closely related Onygenales. The introns contain complete or truncated ORFs with high similarity to homing endonucleases of the LAGLIDADG and GIY-YIG families. Phylogenetic comparison of the mtDNA and nucDNA genomes shows discordance, possibly due to differences in patterns of inheritance. In summary, this work represents the first complete assessment of mitochondrial genomes among several isolates of both species of Coccidioides, and provides a foundation for future functional work.

genomics↗

P-elements strengthen reproductive isolation within the Drosophila simulans species complex

Determining mechanisms that underlie reproductive isolation is key to understanding how species boundaries are maintained in nature. Transposable elements (TEs) are ubiquitous across eukaryotic genomes. However, the role of TEs in modulating the strength of reproductive isolation between species is poorly understood. Several species of Drosophila have been found to harbor P-elements (PEs), yet only D. simulans is known to be polymorphic for their presence in wild populations. PEs can cause reproductive isolation between PE-containing (P) and PE-lacking (M) lineages of the same species. However, it is unclear whether they also contribute to the magnitude of reproductive isolation between species. Here, we use the simulans species complex to assess whether differences in PE status between D. simulans and its sister species, which do not harbor PEs, contribute to multiple barriers to gene flow between species. We show that crosses involving a P D. simulans father and an M mother from a sister species exhibit lower F1 female fecundity than crosses involving an M D. simulans father and an M sister-species mother. Our results suggest that the presence of PEs in a species can strengthen isolation from its sister species, providing evidence that transposable elements can play a role in reproductive isolation and facilitate the process of speciation. IMPACT SUMMARYTransposable elements (TEs) are repetitive genetic units found across the tree of life. They play a fundamental role on the evolution of each species genome. TEs have been implicated in diversification, extinction, and the origin of novelty. However, their potential role in contributing to the maintenance of species boundaries remains largely understudied. Using whole genome sequences, we compared the relative content of TEs across the three species of the Drosophila simulans complex. We find that the presence of one TE, P-element, in D. simulans, and its absence in the sister taxa, differentiates the three species. P-elements (PEs) cause a suite of fitness defects in Drosophila pure-species individuals if their father has PEs but their mother does not, a phenomenon known as hybrid dysgenesis (HD). We thus studied the possibility that PEs enhance isolation between recently-diverged species. In particular, we studied whether the progeny from interspecific crosses were more prone to suffer from HD than pure species. We found that the presence of paternal PEs reduces hybrid female fecundity, mirroring observations of HD described within species. The effect of PEs is stronger in the interspecific hybrids than in pure species. Our results suggest that PEs can strengthen reproductive isolation in well-formed sister species that still hybridize in nature and pose the question of whether other TEs are involved in the formation of species or in their persistence over time.

evolutionary biology↗