Abstract Detail

Hybrids and Hybridization

McAssey, Edward [1], Grimwood, Jane [2], Schmutz, Jeremy [2], Heyduk, Karolina [3], Leebens-Mack, Jim [4].

The leftovers: using chloroplast and transposon data to describe the derivation of a homoploid hybrid species, Yucca gloriosa.

The number of whole genome sequencing projects has deeply expanded our understanding of plant evolution. However, the utility of certain types of sequence data, such as repetitive and organellar DNA reads, is often overlooked and underappreciated. In the genus Yucca, Y. aloifolia (CAM) and Y. filamentosa (C3) have hybridized to form a homoploid hybrid species, Y. gloriosa, that exhibits among-genotype variation along the CAM-C3 photosynthetic pathway continuum. Over 80x coverage of whole genomes have been generated across the genomes of the parental and hybrid Yucca species. As the parental genomes are being assembled, “leftover” shotgun sequence data can help address a number of questions about the origin and early evolution of Y. gloriosa, especially as the genomic impact of hybridization in homoploids are understudied relative to allopolyploids. First, we used whole genome re-sequencing data to assemble whole chloroplast genomes from 5 Y. aloifolia, 12 Y. flimentosa, and 24 Y. gloriosa genotypes. We assessed within species variation and asked whether the origin of Y. gloriosa involved a single or few transfers of Y. filamentosa pollen to Y. aloifolia stigmas, as previous work has suggested. Additionally, repetitive DNA is known to drive differences in genome sizes, and promote potentially adaptive phenotypic variation by affecting the structure or regulation of protein sequences. Further the mixing of two diverged genomes as a consequence of hybridization has been hypothesized to activate certain classes of transposons. By looking at the repetitive content of the three Yucca species, we can begin to understand the degree of divergence between the two parental species, to assess variation in repeat content within and among species, and finally to test whether hybridization activated transposons and resulted in a novel constellation of repeats in Y. gloriosa.

1 - Quinnipiac University, Biological Sciences, 275 Mount Carmel Avenue, Hamden, Connecticut, 06518, United States
2 - HudsonAlpha Institute for Biotechnology, Huntsville, AL
3 - Yale University, Department of Ecology and Evolutionary Biology, 165 Prospect Street, New Haven, CT, 06520, United States
4 - University Of Georgia, Plant Biology, 2101 Miller Plant Sciences, Athens, GA, 30602, United States


Presentation Type: Oral Paper
Abstract ID:565
Candidate for Awards:Margaret Menzel Award

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