**** Mean mapped read length includes adapter and reverse strand sequences.
As shown in Figure 1, the number of markers per chromosome in the consensus map ranged from 27 to 66 SNPs (with a mean of 43); map length per chromosome ranged from 126 to 207 cM, with a mean of 147 cM.
The large number of markers used here (relative to other passerine maps), means that differences in map length between passerines and chickens cannot be attributed to differences in genome coverage.
The generated eight LGs-based genetic maps spanned a total map length of 1,311.9 cM, with a mean inter-marker distance of 0.212 cM (Table 1).
On the other hand, the map constructed by Blair et al. [ 33] contained 118 loci with a total map length of 726.0 cM and a mean marker density of 6.2 cM per locus.
For each map, progeny size (n), map length (cM; total for all 11 linkage groups), mean marker interval (MMI; average for all 11 linkage groups) and total number of mapped markers (using only those linkage groups included in composite map construction; see Methods) are given.
The increase in the number of markers, together with a small reduction in the overall calculated map length, has resulted in a modest improvement in mean marker density of 0.3 cM; our latest map has a density of 1.2 cM per marker or 1.5 cM per unique locus, compared with 1.5 and 1.8 cM, respectively, in our previous map.
The consensus map spanned a total map length of 530 cM and provided the means to propose a standardised linkage group nomenclature for Rosa.
Although marginally significant, the higher mean recombination found in B493 may help explain its larger observed total map length.
