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Table 2 Embryo loss among progeny of NTD heterozygous mutant intercrosses

From: Does dietary folic acid supplementation in mouse NTD models affect neural tube development or gamete preference at fertilization?

Mutant, Diet

Obs. no. embryos

P-value (χ2)

% Lost heterozygous, homozygous

% Lost (combined)

% resorbed (n)

Ave. litter size (n)

+/+

+/−

−/−

Apob tm1Unc

2 ppm

24

48

27

ns

--

--

12.3 (14)

6.2 (16)

10 ppm

40

38

27

0.004 (11.2)

52.5, 32.5

45.8

7.8 (9)

5.8 (18)

Vangl2 Lp

2 ppm

13

41

15

ns

--

--

9.2 (7)

4.3 (16)

10 ppm

23

32

11

0.11 (4.4)

(30.4, 52.2)

37.7

9.6 (7)

4.4 (15)

  1. All embryos were genotyped. Only genotyped embryos were included in litter size metrics. Resorptions were not genotyped. Chi-square goodness-of-fit tests were used to determine whether the observed genotypic distribution of embryos deviated significantly from Mendelian expectations (1:2:1) for the two NTD models and for the two FA diets. The P-value for this test is provided. To calculate the percentage of “embryo loss”, we assumed that the observed number of wild-type embryos was the correct number for the 1:2:1 Mendelian distribution. From this, we estimated expected numbers of heterozygous and mutant homozygous embryos, and then calculated the difference between the expected and observed numbers. The percent embryo loss was calculated for Apob (10 ppm) where genotyping results differed significantly from Mendelian expectations (bold numbers). The percent embryo loss is also provided in parentheses for Vangl2 where a strong but non-significant trend was found. Note that differences in resorptions and litter size did not account for percent embryo loss. Bold numbers highlight results of particular interest. ns, not significant; na, not applicable.