High-Resolution Radiation Hybrid Map of Wheat Chromosome 1D

Abstract

Physical mapping methods that do not rely on meiotic recombination are necessary for complex polyploid genomes such as wheat (Triticum aestivum L.). This need is due to the uneven distribution of recombination and significant variation in genetic to physical distance ratios. One method that has proven valuable in a number of nonplant and plant systems is radiation hybrid (RH) mapping. This work presents, for the first time, a high-resolution radiation hybrid map of wheat chromosome 1D (D genome) in a tetraploid durum wheat (T. turgidum L., AB genomes) background. An RH panel of 87 lines was used to map 378 molecular markers, which detected 2312 chromosome breaks. The total map distance ranged from $3,341 cR 35,000 for five major linkage groups to 11,773 cR 35,000 for a comprehensive map. The mapping resolution was estimated to be $199 kb/break and provided the starting point for BAC contig alignment. To date, this is the highest resolution that has been obtained by plant RH mapping and serves as a first step for the development of RH resources in wheat.

Quantitative Trait Loci and Crop Performance under Abiotic Stress: Where Do We Stand?: Table I.

“…TILLING [Till et al, 2007] and RNA interference [Lukens and Zhan, 2007]). In polyploid species, high-resolution mapping using radiation-induced deletion lines (Kalavacharla et al, 2006) offers a useful route to cloning QTLs in regions that are low in polymorphism or recombination. In maize, a substantial advancement in QTL discovery and cloning has been made possible through the adoption of the nested-association mapping (NAM) system (Yu et al, 2008).…”

A Sequence-Ready Physical Map of Barley Anchored Genetically by Two Million Single-Nucleotide Polymorphisms

“…Genome-wide high-density genotyping of several hundred or even thousands of individuals has been made possible by cost-effective genotyping by sequencing (Elshire at al., 2011;Poland et al, 2012). Apart from recombination-based mapping, radiation hybrid panels similar to those implemented in wheat (Kalavacharla et al, 2006) or obtained for barley by the activity of gametocidal chromosomes (Masoudi-Nejad et al, 2005) may be of value. Similarly, fluorescent in situ hybridization mapping (Cheng et al, 2001) and optical mapping (Zhou et al, 2009) hold some promise and may be used to order markers in recombinogenically inert regions.…”

Molecular mapping of the suppressor gene Igc1 to the gametocidal gene Gc3-C1 in common wheat

“…One of the methods to achieve the high resolution mapping in the recombination-depleted region of genome is the radiation hybrid (RH) mapping (Goss and Harris, 1975;Riera-Lizarazu et al, 2008). Kalavacharla et al (2006) constructed a high-resolution physical map of chromosome 1D by irradiation treatment to wheat seed. This RH mapping approach allowed ordering molecular markers previously unordered within a chromosomal bin, and RH maps with the required resolution can be produced by altering the dosage of radiation.…”