Recent history of artificial outcrossing facilitates whole-genome association mapping in elite inbred crop varieties.
Genomewide association studies depend on the extent of linkage disequilibrium (LD), the number and distribution of markers, and the underlying structure in populations under study. Outbreeding species generally exhibit limited LD, and consequently, a very large number of markers are required for effective whole-genome association genetic scans. In contrast, several of the world's major food crops are self-fertilizing inbreeding species with narrow genetic bases and theoretically extensive LD. Together these are predicted to result in a combination of low resolution and a high frequency of spurious associations in LD-based studies. However, inbred elite plant varieties represent a unique human-induced pseudo-outbreeding population that has been subjected to strong selection for advantageous alleles. By assaying 1,524 genomewide SNPs we demonstrate that, after accounting for population substructure, the level of LD exhibited in elite northwest European barley, a typical inbred cereal crop, can be effectively exploited to map traits by using whole-genome association scans with several hundred to thousands of biallelic SNPs.
Rostoks
Nils
N
Genetics Programme and Biomathematics and Statistics Scotland, Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, Scotland.
Ramsay
Luke
L
MacKenzie
Katrin
K
Cardle
Linda
L
Bhat
Prasanna R
PR
Roose
Mikeal L
ML
Svensson
Jan T
JT
Stein
Nils
N
Varshney
Rajeev K
RK
Marshall
David F
DF
Graner
Andreas
A
Close
Timothy J
TJ
Waugh
Robbie
R
D003433:Crosses, Genetic; D018745:Genome, Plant; D006239:Haplotypes; D001467:Hordeum / Q000235:genetics*; D007178:Inbreeding; D015810:Linkage Disequilibrium; D020641:Polymorphism, Single Nucleotide