Between Dec 19, 2024 and Jan 2, 2025, datasets can be submitted to DRUM but will not be processed until after the break. Staff will not be available to answer email during this period, and will not be able to provide DOIs until after Jan 2. If you are in need of a DOI during this period, consider Dryad or OpenICPSR. Submission responses to the UDC may also be delayed during this time.

Browsing by Author "Spear, Marissa M"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Resurrecting Urban Sunflowers: Phenotypic and Molecular Changes between Antecedent and Modern Populations Separated by 36 Years
    (2023-08-07) Spear, Marissa M; Levi, Sophie J; Etterson, Julie R; Gross, Briana L; blgross@d.umn.edu; Gross, Briana L; University of Minnesota - Duluth Department of Biology
    Resurrection experiments provide a unique opportunity to evaluate phenotypic and molecular evolution in response to environmental challenges. To understand evolution of urban populations of Helianthus annuus, we compared plants from 36-year-old antecedent seed collections to modern seed collections from the same area using molecular and quantitative genetic approaches. We found 200 differentially expressed transcripts between antecedent and modern groups, and transcript expression was generally higher in modern samples as compared to antecedent samples. Admixture analysis indicated gene flow from domesticated to modern populations over time. After a greenhouse refresher generation, one antecedent-modern population pair was grown under two water availability (well-watered and drought) and temperature (ambient and elevated by 2.8°C) conditions reflecting historical and contemporary climates. Overall, 78% (7 out of 9) of traits differed between the antecedent and modern populations, with modern individuals displaying some trait changes that are coherent with climate changes expectations and some trait changes in the direction of crop varieties. Phenotypic selection analysis showed that modern trait values were often favored by selection, especially in environmental treatments resembling modern conditions. Trait heritability in the antecedent population was twice as high as in the modern population, on average. In addition, phenotypic plasticity for some traits, such as flowering phenology, was present in the antecedent population but absent in the modern population. The combination of phenotypic and molecular information suggests that evolution has been influenced by crop-wild introgression, adaptive processes, and drift. We discuss these results in the context of continued evolution in response to anthropogenic factors.
  • Thumbnail Image
    Item
    Sunflower Evolution and Adaption to Climate Change
    (2021-04-30) Levi, Sophie J; Spear, Marissa M; Etterson, Julie R; Gross, Briana L
    Temperatures in Minnesota will rise drastically in the next several decades, and it is important to understand how plants will react to this climate change. Some researchers have studied these reactions with resurrection studies, in which modern and antecedent plant lines are grown in a common environment to monitor evolution thus far and possible adaption to new environments. However, few studies have investigated the hybrid progeny of these resurrected lines. The hybrids serve as a study system for understanding evolution and maternal effects. We investigated these hybrid progeny from a resurrection study of Helianthus annuus and found surprising phenotypic plasticity, decreased transgenerational plasticity in warmer temperatures, and introgression from cultivated varieties.