NASC

Donated by

• Paula Kover Department of Biology and Biochemistry, University of Bath

Click here to view all 527 of these lines.

Description

The Multiparent Advanced Generation Inter-Cross (MAGIC)

The Multiparent Advanced Generation Inter-Cross (MAGIC) is an alternative resource for the genetic dissection of complex traits. This uses a large population of inbred lines derived from intercrossing 19 parents, which is better to localize the genes underlying quantitative traits than the existing methods. The MAGIC lines consist of a set of 527 recombinant inbred lines (RILs) descended from a heterogeneous stock of 19 intermated accessions of the plant Arabidopsis thaliana. These 527 lines and the 19 founders were genotyped with 1,260 single nucleotide polymorphisms and phenotyped for0 development-related traits. Analytical methods were developed to fine-map quantitative trait loci (QTL) in the MAGIC lines by reconstructing the genome of each line as a mosaic of the founders described in Kover, P.X. et al. (2009).

The MAGIC lines are available as a set (N782242):

Nasc code	Description	Stock contents
N782242	Set of Multiparent Advanced Generation Inter-Cross (MAGIC)	View set contents

Construction of the MAGIC lines

The MAGIC lines were initiated by intermating the 19 ‘‘founder’’ accessions of A. thaliana listed in the Table below (Parental Lines), for 4 generations, to create an outbred population.

Accessions chosen for crossing

The founders were selected either because they originate over a wide geographical distribution or are commonly used (i.e. Col-0 and Ler-0). The intermating produced 342 F4 outcrossed families. From each F4 family up to 3 inbred MAGIC lines (MLs) were derived by selfing an F4 plant for six generations. Lines derived from the same F4 can be thought of as ‘‘cousins’’, as they are expected to share 25% of their genomes by descent.

Creating the outbred population.

Intermating was initiated with a complete diallel cross for which each accession was crossed with all other accessions as a maternal and paternal parent, yielding 342 F1 progeny. These F1 were then further intermated through four generations of random mating to produce 342 F5 families. In every generation, two plants from each family were randomly chosen to be paternal and maternal parents (providing an effective population size N e = 684). Assortative mating between plants that have similar flowering time was prevented by staggering planting schedules and planting the same families multiple times. To avoid assortative mating during the mixing of the accessions, a staggered planting scheme was used and families replanted as needed to perform the randomly assigned crosses.

MAGIC Lines: A useful resource

The MAGIC lines are a new panel of genetically diverse and highly recombinant inbred lines of A. thaliana. Like other recombinant inbred lines they do not require repeated genotyping, and since unlimited replicates of each line can be grown, data for many traits can be accumulated, facilitating the study of trait correlations, genotype by environmental interactions, and the genetic basis of phenotypic plasticity. They represent a significant improvement over standard RILs descended from just two founders in that they capture more of the genetic and phenotypic variation present. Furthermore, they have a higher density of recombinants, which improves mapping resolution. Hence the mapping accuracy and detection is much improved in the MLs when compared to traditional two-parent F2 and RIL mapping populations (Kover, P.X. et al. 2009). Consequently, the MLs are an important new tool for the study of the genetic basis of plant growth and yield under multiple environments. Improved understanding of the genetic basis of such quantitative traits is important for the improvement of crop varieties, and to improve our basic knowledge of plant form, growth and development.

Parental lines

Further information on MAGIC lines, crosses and pedigree

This excel file contains a list of all MAGIC lines, the F4 family they are derived from, and the accessions that entered each pedigree.

References

• Kover, P.X. et al. 2009. A Multiparent Advanced Generation Inter-Cross to Fine-Map Quantitative Traits in Arabidopsis thaliana. PLoS Genetics 5(7):e1000551.PubMed ID: 19593375.