For Chr8, we also tested the linkage to resistance of three of the four identified regions, in 48 selected strongly resistant F4 individuals of the cross SICS/SRB that had survived at a high dose of 0.8 mg L-1.
This may be due to genetic linkage between resistance mechanisms and, therefore, co-selection by using only 1 antimicrobial agent (31 ), or to the reservoir of molecular resistance mechanisms in species of commensal flora (33 ).
To further validate the linkage of resistance to the Pi2/9 locus, all the susceptible plants for each BC3F2 population underwent genotyping with Pi2/9-RH.
One proposed factor is a linkage between resistance genes and genes conferring selective advantage to colonize the intestinal lumen of calves.
The pre-conditions for this mechanism to operate are (i) diversifying selection from phage, and (ii) some form of genetic linkage between resistance and fitness.
As a consequence, evidence of linkage to resistance was not deduced by the comparison of the frequency of the markers in the two bulks, but by comparing their frequency deviation from the expected 50% and their deduced genomic localization.
Two P450 cDNAs, CYP6A36 and CYP6A5v2, have recently been identified as being constitutively overexpressed in ALHF and mapped on autosome 5 [ 27, 28], which is correlated with the linkage of resistance in ALHF.
Linkage of resistance and maturity QTL in potato was noted on chromosome 5, which is syntenic to tomato chromosome 5 (Collins et al. 1999; Oberhagemann et al. 1999; Visker et al. 2003; Bradshaw et al. 2004; Visker et al. 2005).
As discussed by Call et al. [ 24] the epidemiology of resistant E. coli in calves is multifactorial, complex and e.g. influenced by co-selection due to linkage of resistance genes.
Both Mi-1.2 and Vat gene belong to the nucleotide-binding-site leucine-rich-repeat (NBS-LRR) family of plant R gene, and there is close linkage between resistance loci and NBS-LRR gene sequences revealed by genetic analysis [ 6, 7].
In mitosis, the cohesin linkages provide resistance and generate tension to facilitate the attachment of sister chromatids to microtubules emanating from opposite poles.
