Papers by Genevieve Kozak
ABSTRACTGenetic variation in life-history timing allows populations to synchronize with seasonal ... more ABSTRACTGenetic variation in life-history timing allows populations to synchronize with seasonal cycles but little is known about the molecular mechanisms that produce differences in circannual rhythm in nature. Changes in diapause timing in the European corn borer moth (Ostrinia nubilalis) have facilitated rapid response to shifts in winter length encountered during range expansion and from climate change, with some populations emerging from diapause earlier to produce an additional generation per year. We identify genomic variation associated with changes in the time spent in winter diapause and show evidence that the circadian clock genes period (per) and pigment dispersing factor receptor (Pdfr) interact to underlie this adaptive polymorphism in circannual rhythm. Per and Pdfr are located within two epistatic QTL, strongly differ in allele frequency among individuals that pupate earlier or later, have the highest linkage disequilibrium among gene pairs in the QTL regions despite...
Female head tissue de novo transcriptome. Longest transcript for each component selected
PIXY statistic for Rock Springs E and Z using amplicon reference
List of annotations for outliers between species (L. goodei vs. L. parva) using blastX and human ... more List of annotations for outliers between species (L. goodei vs. L. parva) using blastX and human proteome. Target gene file used in GO enrichment analyses
This file contains 454 EST sequences that were used as a reference for assembling our new Illumin... more This file contains 454 EST sequences that were used as a reference for assembling our new Illumina reads. These EST sequences were created using pooled DNA from several populations. See the ReadMe file for further details. Dassanayake M, Haas JS, Bohnert HJ, Cheeseman JM (2009) Shedding light on an extremophile lifestyle through transcriptomics. New Phytologist 183, 764-775
Linkage maps are important tools in evolutionary genetics and in studies of speciation. We perfor... more Linkage maps are important tools in evolutionary genetics and in studies of speciation. We performed a karyotyping study and constructed high-density linkage maps for two closely related killifish species, Lucania parva and Lucania goodei, that differ in salinity tolerance and still hybridize in their contact zone in Florida. Using SNPs from orthologous EST contigs, we compared synteny between the two species to determine how genomic architecture has shifted with divergence. Karyotyping revealed that L. goodei possesses 24 acrocentric chromosomes (1N) while L. parva possesses 23 chromosomes (1N), one of which is a large metacentric chromosome. Likewise, high-density SNP-based linkage maps indicated 24 linkage groups for L. goodei and 23 linkage groups for L. parva. Synteny mapping revealed two linkage groups in L. goodei that were highly syntenic with the largest linkage group in L. parva. Together, this evidence points to the largest linkage group in L. parva being the result of a chromosomal fusion. We further compared synteny between Lucania with the genome of a more distant teleost relative medaka (Oryzias latipes) and found good conservation of synteny at the chromosomal level. Each Lucania linkage group had a single best match with each medaka chromosome. These results provide the groundwork for future studies on the genetic architecture of reproductive isolation and salinity tolerance in Lucania and other Fundulidae
Female stickleback preference for conspecific and heterospecific males in only second trials (120... more Female stickleback preference for conspecific and heterospecific males in only second trials (120 minutes after first trial). Data collected in laboratory no-choice mating trials. Column headings in ReadMe file
Preference of female sticklebacks for conspecific and heterospecific males in first and second tr... more Preference of female sticklebacks for conspecific and heterospecific males in first and second trials (two entries per female). Data collected in laboratory no-choice mate trials. Column headings in ReadMe file
Differences in preference measures of female sticklebacks (benthics and limnetics) for two males ... more Differences in preference measures of female sticklebacks (benthics and limnetics) for two males seen 120 minutes apart. Differences calculated as second male minus first male. Difference in red throat coloration between males also included. Data collected in laboratory no-choice mate trials. Column headings in ReadMe file
Each row represents a single behavioral trial and the preference measures associated with that tr... more Each row represents a single behavioral trial and the preference measures associated with that trial. Each female was tested twice so there are two rows per female. See Readme file for column descriptions
Latency to mate (in days) when Indian River L. parva (IR-sympatric) were paired with Blue Springs... more Latency to mate (in days) when Indian River L. parva (IR-sympatric) were paired with Blue Springs L. goodei (BS-allopatric). Data for Figure A5
Journal of Evolutionary Biology, 2020
Adaptation to different environments can directly and indirectly generate reproductive isolation ... more Adaptation to different environments can directly and indirectly generate reproductive isolation between species. Bluefin killifish (Lucania goodei) and rainwater killifish (L. parva) are sister species that have diverged across a salinity gradient and are reproductively isolated by habitat, behavioural, extrinsic and intrinsic post‐zygotic isolation. We asked if salinity adaptation contributes indirectly to other forms of reproductive isolation via linked selection and hypothesized that low recombination regions, such as sex chromosomes or chromosomal rearrangements, might facilitate this process. We conducted QTL mapping in backcrosses between L. parva and L. goodei to explore the genetic architecture of salinity tolerance, behavioural isolation and intrinsic isolation. We mapped traits relative to a chromosome that has undergone a centric fusion in L. parva (relative to L. goodei). We found that the sex locus appears to be male determining (XX‐XY), was located on the fused chromosome and was implicated in intrinsic isolation. QTL associated with salinity tolerance were spread across the genome and did not overly co‐localize with regions associated with behavioural or intrinsic isolation. This preliminary analysis of the genetic architecture of reproductive isolation between Lucania species does not support the hypothesis that divergent natural selection for salinity tolerance led to behavioural and intrinsic isolation as a by‐product. Combined with previous studies in this system, our work suggests that adaptation as a function of salinity contributes to habitat isolation and that reinforcement may have contributed to the evolution of behavioural isolation instead, possibly facilitated by linkage between behavioural isolation and intrinsic isolation loci on the fused chromosome.
ABSTRACTTheory predicts that when different barriers to gene flow become coincident, their joint ... more ABSTRACTTheory predicts that when different barriers to gene flow become coincident, their joint effects enhance reproductive isolation and genomic divergence beyond their individual effects, but empirical tests of this ‘coupling’ hypothesis are rare. Here, we analyze patterns of gene exchange among populations of European corn borer moths that vary in the number of acting barriers, allowing for comparisons of genomic variation when barrier traits or loci are in coincident or independent states. We find that divergence is mainly restricted to barrier loci when populations differ by a single barrier, whereas the coincidence of temporal and behavioral barriers is associated with divergence of two chromosomes harboring barrier loci. Furthermore, differentiation at temporal barrier loci increases in the presence of behavioral divergence and differentiation at behavioral barrier loci increases in the presence of temporal divergence. Our results demonstrate how the joint action of coincid...
Nature Communications, 2021
The sex pheromone system of ~160,000 moth species acts as a powerful form of assortative mating w... more The sex pheromone system of ~160,000 moth species acts as a powerful form of assortative mating whereby females attract conspecific males with a species-specific blend of volatile compounds. Understanding how female pheromone production and male preference coevolve to produce this diversity requires knowledge of the genes underlying change in both traits. In the European corn borer moth, pheromone blend variation is controlled by two alleles of an autosomal fatty-acyl reductase gene expressed in the female pheromone gland (pgFAR). Here we show that asymmetric male preference is controlled by cis-acting variation in a sex-linked transcription factor expressed in the developing male antenna, bric à brac (bab). A genome-wide association study of preference using pheromone-trapped males implicates variation in the 293 kb bab intron 1, rather than the coding sequence. Linkage disequilibrium between bab intron 1 and pgFAR further validates bab as the preference locus, and demonstrates tha...
Understanding how speciation occurs and how reproductive barriers contribute to population struct... more Understanding how speciation occurs and how reproductive barriers contribute to population structure at a genomic scale requires elucidating the genetic architecture of reproductive isolating barriers. In particular, it is crucial to determine if loci underlying reproductive isolation are genetically linked or if they are located on sex chromosomes, which have unique inheritance and population genetic properties. Bluefin killifish (Lucania goodei) and rainwater killifish (L. parva) are closely related species that have diverged across a salinity gradient and are reproductively isolated by assortative mating, hybrid male infertility, viability of hybrid offspring at high salinities, as well as reduced overall fitness of F2 offspring and backcrosses to L. goodei. We conducted QTL mapping in backcrosses between L. parva and L. goodei to determine the genetic architecture of sex determination, mate attractiveness, fertility, and salinity tolerance. We find that the sex locus appears to ...
Molecular ecology, Jan 31, 2017
Chromosomal rearrangements between sympatric species often contain multiple loci contributing to ... more Chromosomal rearrangements between sympatric species often contain multiple loci contributing to assortative mating, local adaptation, and hybrid sterility. When and how these associations arise during the process of speciation remains a subject of debate. Here, we address the relative roles of local adaptation and assortative mating on the dynamics of rearrangement evolution by studying how a rearrangement co-varies with sexual and ecological trait divergence within a species. Previously, a chromosomal rearrangement that suppresses recombination on the Z (sex) chromosome was identified in European corn borer moths (Ostrinia nubilalis). We further characterize this recombination suppressor and explore its association with variation in sex pheromone communication and seasonal ecological adaptation in pairs of populations that are divergent in one or both of these characteristics. Direct estimates of recombination suppression in pedigree mapping families indicated that more than 39% o...
Ecology and Evolution, 2013
Female mate preferences for ecologically relevant traits may enhance natural selection, leading t... more Female mate preferences for ecologically relevant traits may enhance natural selection, leading to rapid divergence. They may also forge a link between mate choice within species and sexual isolation between species. Here, we examine female mate preference for two ecologically important traits: body size and body shape. We measured female preferences within and between species of benthic, limnetic, and anadromous threespine sticklebacks (Gasterosteus aculeatus species complex). We found that mate preferences differed between species and between contexts (i.e., within vs. between species). Within species, anadromous females preferred males that were deep bodied for their size, benthic females preferred larger males (as measured by centroid size), and limnetic females preferred males that were more limnetic shaped. In heterospecific mating trials between benthics and limnetics, limnetic females continued to prefer males that were more limnetic like in shape when presented with benthic males. Benthic females showed no preferences for size when presented with limnetic males. These results show that females use ecologically relevant traits to select mates in all three species and that female preference has diverged between species. These results suggest that sexual selection may act in concert with natural selection on stickleback size and shape. Further, our results suggest that female preferences may track adaptation to local environments and contribute to sexual isolation between benthic and limnetic sticklebacks.
International Journal of Evolutionary Biology, 2012
Divergent natural selection has the potential to drive the evolution of reproductive isolation. T... more Divergent natural selection has the potential to drive the evolution of reproductive isolation. The euryhaline killifishLucania parvahas stable populations in both fresh water and salt water.Lucania parvaand its sister species, the freshwaterL. goodei, are isolated by both prezygotic and postzygotic barriers. To further test whether adaptation to salinity has led to the evolution of these isolating barriers, we tested for incipient reproductive isolation withinL. parvaby crossing freshwater and saltwater populations. We found no evidence for prezygotic isolation, but reduced hybrid survival indicated that postzygotic isolation existed betweenL. parvapopulations. Therefore, postzygotic isolation evolved before prezygotic isolation in these ecologically divergent populations. Previous work on these species raised eggs with methylene blue, which acts as a fungicide. We found this fungicide distorts the pattern of postzygotic isolation by increasing fresh water survival inL. parva, mask...
The American Naturalist, 2015
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Trends in Ecology & Evolution, 2013
magnifies the effect of genotypic differences in the novel courtship trait on fitness, which is e... more magnifies the effect of genotypic differences in the novel courtship trait on fitness, which is expected to facilitate its evolution. Learning may also expedite evolution of novel morphological mating traits. For example, if males learn to use tail fanning to solicit matings, this is likely to generate sexual selection for tail size and/or tail ornaments; this selection would be weak or absent if tail fanning were only expressed at the low, genetically based level. The above scenario may seem specific. Nonetheless, theoretical studies, although not specifically designed to address sexual selection or speciation, do suggest that learning facilitates a genetically based response to novel selection under rather broad conditions, in particular if the relation between trait value and fitness involves a threshold or is convex [3,5]. That these models are not biologically unrealistic has been demonstrated in an evolutionary experiment on Drosophila, in which learning facilitated the genetic evolution of preference for an initially nonpreferred resource [8]. Therefore, the notion that learning of mating traits may facilitate speciation under divergent sexual or natural selection deserves more attention from both theoretical and empirical research.
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Papers by Genevieve Kozak