Table 5.

Comparison of Chromosome 4 and 11 ENU Balancer Screens

Parameter	Chr 4 (117–281)	Chr 4 (281–51)	Chr 11 (Trp53-Wnt3)
Interval Breakpoints	96.4–129.8 Mb	129.8–154.4 Mb	69.4–103.7 Mb
Interval size	33 Mb	25 Mb	34 Mb
Number of annotated genes	470	461	905
Pedigrees screened	530	551	785
Lethal lines	11	19	59
Other viable phenotypes	0	4	32
Total mutations	11	23	91
Mutations/Mb	0.33	0.92	2.68
Homogeneity of samplesa	3.913, p < 0.05	22.8, p < 0.001	37.2, p < 0.001
Frequency of mutations mapping outside of the balancer region	1 in 5.4	1 in 4.8	1 in 4.2
Literature Reference	This report	Hentges et al. 2006 [4]	Kile et al. 2003 [5]

In all cases, the phenotype screen included a coat color screen for all lethals in the balancer region. It also included a complete blood count for all blood cell parameters, a screen for neutral cholesterols using tandem mass spectrometry, a urine screen for albumin and glucose, and a general visual assessment of skin, coat, eyes, fur, movement and balance, as well as morphology on all viable mice, which would carry mutations segregating to the balancer region or elsewhere in the genome.

^a A Chi square test for homogeneity of samples in a binomial distribution with one degree of freedom. The values represent the significance from the numbers of mutations isolated in the next column, with the exception that the number in column c is the difference from column a.