London fought back, crossing to the left of the posts when Caton-Brown got his second on the back of good work from Scott Moore and Maxime Herold.
The analysis of several F3 lines derived from a back-cross of the CSSL4 or CSSL19 lines allowed us to confirm that chromosome 1 was sufficient to confer nitrogen-induced susceptibility (Families 4 40; Additional file 1: Table S2).
Hybridization in the Gulf Coast appears to be due to back-crossing of the P. mauritianus × P. australis hybrid (haplotype I) with P. australis haplotypes (M, M1, AD and AI) (Fig. 1).
The low GLUD activity and low GLUD1 protein levels thus led us to select the Balb/c mouse strain for the back-crossing of the Glud1 Tg mouse founders.
Following back-crossing of the Tg mice to the Balb/c strain, we measured the effects that introduction of the Glud1 gene had on basal extracellular glutamate levels and on depolarization-induced glutamate release from striatal neurons in these mice and compared such release with that observed in littermate wt mice and C57BL/6 mice overexpressing the same transgene.
We obtained wild type (WT) C57B6 mice from the Jackson Laboratory (Houston, TX) and produced ER-α KO mice by back-cross of the previously generated heterozygous ER-α KO mice (Lambert et al. 2005).
Back-crossing of hybrids with the Amur wild carp was performed in only one generation (third).
The tremendous power of this approach is evident from the fact that, after only three cycles of back crossing, the selected F3 segregant IMS0344 retained only three mutations of which, after reverse engineering, two were shown to directly contribute to butanol tolerance of the original evolved strain.
Interestingly, Palmer et al. (1983) [ 31] predicted from chloroplast DNA analysis that back-crossing of a novel hybrid to the paternal parent population must have occurred several times during the evolution of B. napus from progenitor species B. rapa and B. oleracea, supporting the triploid bridge mechanism of polyploid formation in this genus.
After five back-crosses, the presence of the ok1789 deletion in genomic DNA was confirmed by PCR amplification using oligonucleotides oNQ1018 and oNQ1019 (supplementary material Table S11) followed by gel electrophoresis.
Thus, this diffusion most likely depicts recent on-going gene flow introducing new alleles into each continental nuclear gene pool by back-crossing in the absence of maternal lineage mixing.
