Recombinant animals and their HcB-19 backcross progeny that define the maximal critical interval containing Hyplip1. a, Recombinant R11 and 10 backcross progeny. Backcross mice are grouped according to the inheritance of a recombinant or nonrecombinant haplotype across the Hyplip1 locus for the seven markers listed at the right. Filled boxes indicate HcB-19 (h) alleles and open boxes denote CAST/Ei (c) alleles. Ketone body (Ket) and triglyceride (TG) levels in mg dl−1 are given for each parental recombinant and their progeny. The predictive probability of heterozygosity, P(c/h), is shown for each parental recombinant, and the average predictive probability of homozygosity, P(h/h), is given for backcross progeny with the same haplotype. The R11 recombinant and all six backcross progeny with the same haplotype have lower β-HB and TG levels as compared with littermates homozygous with respect to HcB-19 alleles. R11 had a high probability of being heterozygous [P(c/h)=0.987] and the backcross progeny had a low probability of homozygosity with respect to Hyplip1 [P(h/h)=0.064], indicating that Hyplip1 is distal to D3Pds7. b, Recombinant R12 and 8 backcross progeny. All six backcross progeny with the parental haplotype have normal β-HB and TG levels, with a low probability of homozygosity with respect to Hyplip1 [P(h/h)=0.156]. Thus, Hyplip1 lies proximal to D3Pds13. c, Recombinant R13 and 3 backcross progeny. As shown, R13 carries Hyplip1 alleles proximal to D3Pds13. Backcross progeny carrying this crossover have increased amounts of β-HB and TG, indicating homozygosity for Hyplip1 with a high probability [P(h/h)=0.959], giving further evidence that Hyplip1 is proximal to D3Pds13. d, Recombinant R14, six backcross progeny, and 90 animals obtained from intercrossing backcross progeny with the crossover breakpoint. R14 had a high probability of being heterozygous [P(c/h)=0.816]. Backcross progeny with the same haplotype have increased amounts of β-HB and TG, indicating homozygosity with respect to Hyplip1 [P(h/h)=0.955]. When these mice are intercrossed, all resultant progeny have increased β-HB and TG levels (the average ± s.e.m. for each genotypic group is shown), providing additional evidence for placing the distal boundary for Hyplip1 at D3Pds13.