Biology subjects

Jameel, M. I.

Publications and source records attributed to Jameel, M. I..

5 recordsLinked to original sources

bioRxiv2026

A fast neutron mutant resource for Ipomoea purpurea reveals dose-dependent genomic and phenotypic variation

A central goal in evolutionary biology is to understand the genomic basis of phenotypic traits, yet this pursuit is often constrained by a lack of accessible phenotypic and genetic variation, particularly in non-model organisms. Fast neutron irradiation offers a powerful approach for generating such variation, as it does not require prior genomic resources, established transformation systems, or reference mutant collections. Here, we describe the development and characterization of the first fast neutron mutant library in Ipomoea purpurea (common morning glory), a noxious agricultural weed and established model system in evolutionary ecology. We exposed an I. purpurea reference genotype to three levels of irradiation and developed 1,043 lines third generation lines and characterized the phenotypic and genetic variation in a subset of 200. Phenotypic screens identified seven mutant lines exhibiting eleven distinct phenotypes, and revealed higher phenotypic variance for anther-stigma distance, flower number, and pollen count relative to a non-irradiated control line. We further identified genetic variation across eight phenotypic traits among the mutant lines. Together, these results show that fast neutron mutagenesis generates novel phenotypic and genetic variation in ecologically relevant traits, offering the research community a new genomic resource for an established model in evolutionary ecology.

plant biology↗

bioRxiv2025

A panel of near-isogenic lines derived from locally adapted populations of a wild plant: A powerful tool for dissecting additive and non-additive effects on ecologically important traits

Identifying and estimating the effects of loci contributing to natural variation in ecologically important traits can be hampered by quantitative inheritance, dominance, epistasis, and environmentally dependent trait expression. Here we announce the availability of germplasm and sequence data for a reciprocal panel of near-isogenic lines (NILs) derived from locally adapted natural populations of Arabidopsis thaliana, for investigating the genetic basis of ecologically important traits. We created a panel of 54 NILs and performed whole genome sequencing to precisely locate introgression segments(s) in each NIL. Deep sequencing largely confirmed prior knowledge of NIL genotypes but also identified multiple novel small introgressions and regions of residual heterozygosity. To illustrate the utility of this panel, we identified genomic regions underlying ecotypic differences in flowering time in a laboratory common garden experiment. We detected strong additive effects on flowering time in multiple NILs with segments at the top of chromosome 5 implicating the floral regulator FLC, as expected based on previous quantitative trait locus studies. We also detected novel and complex contributions to ecotypic differences in flowering time, only visible in the NILs, suggesting the possibility of epistasis. Our results highlight the utility of this panel for dissecting the genetic architecture of ecologically important traits, including the future potential for fine mapping of additive effects and testing for epistasis and linkage using NILs derived from the panel. This panel can be used by any member of the research community to investigate any of a broad suite of traits for which the parents differ.

evolutionary biology↗

bioRxiv2020

Climate change alters plant-herbivore interactions

Plant-herbivore interactions have evolved in response to co-evolutionary dynamics, along with selection driven by abiotic conditions. We examine how abiotic factors influence trait expression in both plants and herbivores to evaluate how climate change will alter this long-standing interaction. The paleontological record documents increased herbivory during periods of global warming in the deep past. In phylogenetically-corrected meta-analyses, we find that elevated temperatures, CO2 concentration, drought stress and nutrient conditions directly and indirectly induce greater herbivore consumption, primarily in agricultural systems. Additionally, elevated CO2 delays herbivore development, but increased temperatures accelerate development. For annual plants, higher temperatures, CO2, and drought stress increase foliar herbivory, and our meta-analysis suggests that greater temperatures and drought may heighten florivory in perennials. Human actions are causing concurrent shifts in CO2, temperature, precipitation regimes and nitrogen deposition, yet few studies evaluate interactions among these changing conditions. We call for additional multifactorial studies that simultaneously manipulate multiple climatic factors, which will enable us to generate more robust predictions of how climate change could disrupt plant-herbivore interactions. Finally, we consider how shifts in insect and plant phenology and distribution patterns could lead to ecological mismatches, and how these changes may drive future adaptation and coevolution between interacting species.

plant biology↗

bioRxiv2020

Selection favors adaptive plasticity in a long-term reciprocal transplant experiment

Spatial and temporal environmental variation can favor the evolution of adaptive phenotypic plasticity, such that genotypes alter their phenotypes in response to local conditions to maintain fitness across heterogeneous landscapes. When individuals show greater fitness in one habitat than another, asymmetric migration can restrict adaptive responses to selection in the lower quality environment. In these cases, selection is predicted to favor traits that enhance fitness in the higher-quality source habitat at the expense of fitness in the marginal habitat, resulting in specialization to the high-quality environment. Here, we test whether plasticity is adaptive in a system regulated by demographic source-sink dynamics. Vaccinium elliottii (Ericaceae) occurs in dry upland and flood-prone bottomland forests throughout the southeastern United States, and shows patterns consistent with source-sink dynamics. We conducted a multi-year field experiment to evaluate whether plasticity in foliar morphology is advantageous. Both across habitats and within the high-quality upland environment, selection favored plasticity in specific leaf area and stomatal density. Stabilizing selection acted on plasticity in these traits, suggesting that extreme levels of plasticity are disadvantageous. We conclude that even in systems driven by source-sink dynamics, temporal and spatial variation in conditions can favor the evolution of plasticity.

evolutionary biology↗

bioRxiv2019

Genetic and physiological mechanisms of freezing tolerance in locally adapted populations of a winter annual

Premise of the studyDespite myriad examples of local adaptation, the phenotypes and genetic variants underlying such adaptive differentiation are seldom known. Recent work on freezing tolerance and local adaptation in ecotypes of Arabidopsis thaliana from Sweden and Italy provides the essential foundation for uncovering the genotype-phenotype-fitness map for an adaptive response to a key environmental stress.\n\nMethodsHere we examine the consequences of a naturally occurring loss of function (LOF) mutation in an Italian allele of the gene that encodes the transcription factor CBF2, which underlies a major freezing tolerance locus. We used four lines with a Swedish genetic background, each containing a LOF CBF2 allele. Two lines had introgression segments containing of the Italian CBF2 allele, and two were created using CRISPR-Cas9. We used a growth chamber experiment to quantify freezing tolerance and gene expression both before and after cold acclimation.\n\nKey resultsFreezing tolerance was greater in the Swedish (72%) compared to the Italian (11%) ecotype, and all four experimental CBF2 LOF lines had reduced freezing tolerance compared to the Swedish ecotype. Differential expression analyses identified ten genes for which all CBF2 LOF lines and the IT ecotype showed similar patterns of reduced cold responsive expression compared to the SW ecotype.\n\nConclusionsWe identified ten genes that are at least partially regulated by CBF2 that may contribute to the differences in cold acclimated freezing tolerance between the Italian and Swedish ecotypes. These results provide novel insight into the molecular and physiological mechanisms connecting a naturally occurring sequence polymorphism to an adaptive response to freezing conditions.

evolutionary biology↗