In order to determine which SNV was causative of the deaf14 phenotype, a meiotic mapping cross was set up.
To test our assumption regarding linkage between lethality and GFP expression, viable recombinant progeny from each mapping cross were examined for the GFP phenotype.
However, for application in molecular breeding strategies, genetic linkage maps based on wide crosses are often of limited utility, as they are not representative of the genome organisation and gene function of the cultivated gene pool [ 30].
The genomic regions or QTLs, which are consistently detected over a range of environments or mapping populations or different parental crosses, are considered "stable or major QTLs" and are preferred targets in crop improvement.
Such mapping crosses can be continued with ever-smaller deletions, until eventually the individual dosage-sensitive genes can be identified by crossing the mouse model with a 'knockout' for the relevant gene.
Second, specific cross types were used to perform the mapping: gynogenetic haploid crosses were used to map both duplicated and nonduplicated loci, and diploid crosses were used to construct sex-specific maps.
For resistance mapping, single-pair crosses were performed between females from the Xen-R colony and males from the FRA colony.
Because multiple alleles with different effects are likely segregating within natural populations (Mauricio 2001), QTL mapping with multiple crosses is necessary to understand the genetic variation underlying phenotypic variation in natural populations (Barnwell and Noor 2008).
The four maps from individual crosses were fused using MergeMap (see Methods) to form a consensus map containing 2943 SNP loci with a total map length of 1099 cM (Table 1).
Six CRC modifiers previously mapped in intraspecific crosses were also replicated.
