EdU labelling index in the hindgut was significantly higher in ct9E than in ct8E embryos (* p,0.02). There was a trend towards increased EdU labelling in the neural folds of ct9E embryos, but this did not reach statistical significance (p = 0.06). (DOCX) Table S4 Primers for sequencing of Lmnb1 exons. All primers are flanking coding regions of the respective exons. Sizes of product-fragments are given in base pairs (bp), including primer sequence. Tu indicates annealing temperature used for PCR amplification. (DOCX) References 1. Nadeau JH (2003) Modifier genes and protective alleles in humans and mice. Curr Opin Genet Dev 13: 290–295. 2. Copp AJ, Greene NDE (2010) Genetics and development of neural tube defects. J Pathol 220: 217–230. 3. Bassuk AG, Kibar Z (2009) Genetic basis of neural tube defects. Semin Pediatr Neurol 16: 101–110. 4. Greene NDE, Stanier P, Copp AJ (2009) Genetics of human neural tube defects. Hum Mol Genet 18: R113–R129. 5. 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