Genotyping by Sequencing of Avena barbata in California

The slender wild oat (Avena barbata) was widely studied in California using allozymes in the 1970s and interpreted as a case of ecotypic adaptation to contrasting moisture environments (e.g., Clegg & Allard. 1972. Proc. Natl. Acad. Sci. U. S. A. 69:1820). This project revisits ca 100 of these sites to examine changes in the genetic composition of these populations over a 40-year interval. Each wild sample was screened for Genotyping by Sequencing (GBS) polymorphisms with known map locations on a recent GBS linkage map (Latta et al, 2019. Sci Rept. 9:12298). his survey documents contemporary evolution at the genetic level over a large geographic scale, and compares the results to common garden and QTL mapping studies of the ecotypes (Latta et al. 2010. Genetics: 185:375-385). The study also documents the arrival and spread of new genotypes introduced to California. Note that in GBS, the barcodes are ligated within the 100 bp sequence read. Thus in the fastq files, sequence prior to the PstI restriction site (CTGCAG) is the barcode. Barcode sequences for each run are included in the description field accompanying each fastq file.