Biology subjects

Albrecht, M. A.

Publications and source records attributed to Albrecht, M. A..

4 recordsLinked to original sources

bioRxiv2026

Genomic Consequences of Altered Flood Regimes: Gene Flow and Adaptation in a Threatened Floodplain Plant

Floodplains are highly dynamic ecotones where species persistence depends on synchrony between natural flow regimes and life-history. Artificial river engineering has profoundly altered these systems by reducing the frequency and magnitude of spring floods while increasing the unpredictability of flood timing and intensity during summer. These hydrological changes have disrupted historical patterns of dispersal, growth, reproduction, and competitive success among floodplain specialists. Effective conservation in these ecosystems therefore requires understanding how human-altered flow regimes have reshaped floodplain specialists' demography, genetic diversity, genetic connectivity, functional variation, and adaptive potential. Here, we address this challenge in Boltonia decurrens, a federally threatened floodplain plant endemic to the Illinois River Valley, by integrating a chromosome-scale reference genome, whole-genome resequencing, and common-garden adaptive trait measurements from 424 individuals across 17 populations. Demographic analyses revealed a severe recent bottleneck and a subsequent rebound. Population structure was clinal with downstream-dominant gene flow, indicating that regional population connectivity predominates over longer-distance gene flow. A subset of populations showed elevated genetic isolation with increased inbreeding and homozygous deleterious burden, revealing a genomic cost of disrupted floodplain connectivity. Common-garden observations and GWAS showed extensive within-population phenotypic and genetic variation in flowering time, flowering stem height, and year of first flowering (1st vs. 2nd year), which are hypothesized to buffer populations and to be selectively maintained under human-altered flow regimes. Finally, landscape-genomic approaches detected a divergent haplotype block separating northern and southern populations, suggesting that adaptive divergence can persist even in a system shaped by recurrent disturbance and ongoing gene flow.

evolutionary biology↗

bioRxiv2026

A disjunct distribution and population fragmentation shape rangewide genetic diversity and structure of the endangered Physaria globosa (Brassicaceae)

Population genetic analysis of species of conservation concern provides information to devise management plans to effectively conserve the genetic variation of endangered species. One such endangered plant, Physaria globosa is a federally endangered species in the mustard family with a geographically restricted range that occurs in four disjunct locations in Indiana, Kentucky, and Tennessee (i.e., Highland Rim and Nashville Basin regions) and along the Wabash, Kentucky, and Cumberland Rivers. In this study, we sampled populations from throughout the range of P. globosa, genotyped them using 20 microsatellite loci, and assessed genetic diversity and structure within and among populations. The goals of the study were to understand: 1) levels of genetic diversity in P. globosa and whether populations show evidence of having experienced reductions in genetic diversity as the result of genetic bottlenecks, genetic drift, or inbreeding, 2) rangewide genetic diversity and structure in P. globosa and how genetic structure is affected by the disjunctions in the species range, and 3) implications for prioritization of in-situ and ex-situ conservation efforts. On average, P. globosa showed comparable levels of genetic diversity to other species of Physaria. However, some populations showed evidence of inbreeding, genetic bottlenecks, or decreases in genetic diversity, possibly due to anthropogenic or climate-related pressures and decreases in population size due to competition with invasive bush honeysuckle. Genetic variation was strongly structured into two main geographic groups, one in the northern part of the species range (KY and IN), and the other in the southern part of the species range (TN), but some populations likely originated via long-distance dispersal. We also found significant isolation by distance, likely due to both life history characteristics and physical barriers associated with the complex topological structure of the landscape occupied by P. globosa, limiting population connectivity. Given the strong genetic structure found in P. globosa, several populations should be protected and managed within each geographic region to conserve genetic variation. Ex situ conservation will also be important to protect genetic diversity, particularly for populations that are difficult to access and manage.

genetics↗

bioRxiv2021

The role of genus and life span in predicting seed and vegetative trait variation and correlation in Lathyrus, Phaseolus, and Vicia (Fabaceae)

PREMISE OF THE STUDYAnnual and perennial life history transitions are abundant among angiosperms, and understanding the phenotypic variation underlying life span shifts is a key endeavor of plant evolutionary biology. Comparative analyses of trait variation and correlation networks among annual and perennial plants is increasingly important as new perennial crops are being developed in a predominately annual-based agricultural setting. However, it remains unclear how seed to vegetative growth trait relationships may correlate with life span. METHODSWe measured 29 annual and perennial congeneric species of three herbaceous legume genera (Lathyrus, Phaseolus, and Vicia) for seed size and shape, germination proportion, and early vegetative height and leaf growth over three months in order to assess relative roles of genus and life span in predicting phenotypic variation and correlation. KEY RESULTSGenus was the greatest predictor of seed size and shape variation, while life span consistently predicted static vegetative growth traits. Correlation networks revealed that annual species had significant associations between seed traits and vegetative traits, while perennials had no significant seed-vegetative associations. Each genus also differed in the extent of integration between seed and vegetative traits, as well as within-vegetative trait correlation patterns. CONCLUSIONSGenus and life span were important for predicting aspects of early life stage phenotypic variation and trait relationships. Differences in phenotypic correlation may indicate selection on seed size traits will impact vegetative growth differently depending on life span, which has important implications for nascent perennial breeding programs.

plant biology↗

bioRxiv2019

Motor Output Matters: A Study on the Neural Correlates of Failed Inhibitory-Control.

Motor actions can be suppressed with varying degrees of success, but this variability is not captured in many experiments where responses are represented in binary (response vs. no-response). Although the Stop/No-go P300 (an enhanced frontocentral positivity in the event-related potential (ERP) peaking around 300 ms after a Stop/No-go stimulus, compared to Go trials) has been implicated as a measure of inhibitory-control, it is unclear how the range of motor outputs relates to the P300. We examined the nature of this association in two experiments using an Anticipatory Timing and a Go/No-go Task. Force, response onset time, and the P300 were measured.\n\nIn both experiments, our results showed that trial-by-trial P300 amplitude on Failed Inhibitions were continuously related to Force, where higher response forces (reflecting a greater degree of error) were associated with smaller P300 amplitudes. Compared to Successful Inhibitions, P300 amplitude was reduced and ERP onset latencies were delayed on Failed Inhibitions. Although the binary categorisation of inhibition-success (Successful vs. Failed) accounted for more variance in the data compared to force, it misses a reliable linear relationship that can be captured by continuous measures of motor output. Overall, the results provide strong evidence that the engagement of inhibitory-control varies on a continuum from trial-to-trial and that this engagement is reflected by the P300. We present an activation-to-threshold model of inhibitory-control to explain our results, which offers a new conceptual framework for describing the implementation of inhibitory-control in highly prepared motor responses. Our results also highlight the importance of studying the spectrum of motor outputs and the need for future models of inhibitory-control to account for motor output.

neuroscience↗