Size Matters…in Genomes

  • 7 December 2018
  • Author: Frederika Bain
  • Number of views: 4112
Size Matters…in Genomes

Come to the Annual Brewbaker Lecture on Genetics & Plant Breeding on Friday, December 14. Jeffrey Ross-Ibarra, a professor in the Department of Plant Sciences Center for Population Biology and the Genome Center, will speak on “Genome Size and Adaptation in Plants” in St. John 106 at 1:30 p.m. As he explains, the vast majority of genome size variation in plants is due to differences in repetitive sequence, but we know little about how this impacts plants in natural populations. He will present two distinct consequences of this variation. First documenting extensive intraspecific variations in genome size using parallel altitudinal clines in maize and its wild relative teosinte, he will use quantitative genetic analysis to show that such variation cannot be due to genetic drift or population structure, implying a role for natural selection. Moving beyond variation within a species, he will discuss the effects of genome size variation among plants, using examples from maize and the model plant Arabidopsis. He will present the “Functional Space” hypothesis, positing that the mode of adaptation—which loci are functional, how natural selection acts, and so on—may depend on genome size. Dr. Ross-Ibarra will end by showing that even in Arabidopsis, which has a small genome, repetitive sequence likely plays an outsized role in adaptation. Together, this work implies a potentially important adaptive role for both intraspecific and interspecific variation in genome size across plants.