Natr vs Nats difference plus background differences
Natr vs Nats difference on Chromosome 8
Nat' vs Nats difference on Chromosome 8
has the desired genotype with homozygosity at both loci (ssdd) of interest; sibling pairs with this genotype are selected to found the double congenic strain. Notice that in contrast to the creation of the inbred strain congenic at a single locus described in Figure 9.2, the creation of the double congenic strain requires only four additional generations.
The naming of double congenic strains follows guidelines similar to those given above for lines congenic at a single genetic locus. Consider the double congenic strain for the Nat locus on chromosome 8 and the Ahr receptor locus on chromosome 12, both placed on the B6 background. This strain has been used to investigate the effects of genetic interactions between the acetylation and Ahr receptor polymorphisms (see pp. 271 and 274). The B6.A-Na^ congenic strain is created from B6 as the normally rapid acetylator background strain and A as the donor strain for the slow acetylator locus, Nats according to the protocol described above (see Figure 9.2). The B6.D-Ahrd congenic strain is created by a similar protocol from B6, a normally high-affinity Ahr receptor background strain and DBA/2 as the donor strain for the low-affinity form of the Ahrd locus. The double congenic line that is created is designated as B6.A-Naf.D-Ah/, abbreviated B6.A.D.
The quartet of strains consisting of the background strain (B6), each of the single congenic strains (B6.A and B6.D), and the double congenic strain (B6.A.D)
F2 Gametes, Female
^rb rd sb sd rb rrbb rrbd rsbb rsbd rd rrbd rrdd rsbd rsdd sb rsbb rsbd ssbb ssbd sd rsbd rsdd ssbd ssdd
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