Abstract Detail

Comparative Genomics/Transcriptomics

Boutte, Julien [1], Fishbein, Mark [2], Coriton, Olivier [3], Rousseau-Gueutin, Mathieu [4], Straub, Shannon [1].

Gene Family Expansion in the Sonoran Desert Clade of Asclepias.

Gene and genome duplications play an important role in the diversification of eukaryotic functions and the formation of new species. Several sources of gene duplication are known including retrotransposition, unequal crossing over, and polyploidy. After gene duplication, several scenarios can occur: one copy can become non-functional (pseudogenization), the new copy can retain the original function, acquire a new function (neofunctionalization), or the ancestral function can be partitioned among copies (subfunctionalization). We explored gene duplication in Asclepias (Apocynaceae, 2n=22), an ecological and evolutionary model for the study of reproductive biology, plant defenses and plant-animal interactions (e.g. coevolution with the monarch butterfly). We focus on a CW-type Zinc finger protein, present in single copy in the majority Asclepias species and shown to be expressed in Asclepias syriaca and Asclepias curassavica. We estimated the copy number of this gene using genomic shotgun data and Hyb-Seq data sets (a combination of target enrichment and genome skimming). This gene has between 10 and 40 copies in species of the Sonoran Desert Clade (SDC) of Asclepias (and up to 105 copies in a hybrid). Some species from the Temperate North American clade have an intermediate copy number (2-6), but outgroup species, like the majority of the Asclepias species have only one copy, indicating probable independent duplications events in the two clades. Gene duplication was validated using fluorescence in situ hybridization (FISH) using three different probes in two species: A. syriaca and Asclepias subulata, a member of the SDC. Characterization at the sequence level showed that several exons and introns are highly conserved, while others are divergent. Analyses are ongoing to compare gene expression between species with one and many copies and to explore the function and consequences of this duplication for the species of the SDC.

1 - Hobart and William Smith Colleges, Department of Biology, 300 Pulteney St., Geneva, NY, 14456, USA
2 - Oklahoma State University, Department of Plant Biology, Ecology, and Evolution, 301 Physical Sciences, Stillwater, OK, 74078, USA
3 - INRA, IGEPP, Agrocampus Ouest, Université de Rennes 1, BP35327, Le Rheu Cedex, 35653, France
4 - INRA, IGEPP, Agrocampus Ouest, Université de Rennes 1, BP35327, Le Rheu, 35653, FRANCE

Keywords:
gene duplication
FISH
Copy Number Estimation.

Presentation Type: Oral Paper
Session: 25, Comparative Genomics and Transcriptomics II
Location: 102/Mayo Civic Center
Date: Tuesday, July 24th, 2018
Time: 3:45 PM
Number: 25011
Abstract ID:614
Candidate for Awards:None