Fig. 2

Genotyping of chicken NRG3. A different pattern of PCR amplification is shown in 1.5% agarose gel electrophoresis. a A set of primers was designed in exon 1 (NRG3_longF) and exon 2 (NRG3_commonR), and used for PCR. b A reverse primer (NRG3_delR2) overlapping with the putative frameshift deletion was used instead of NRG3_commonR. Note that much fainter bands can be seen in the chickens with the putative frameshift mutation (del) in panel b. Marker: ϕX174/HaeIII digest. c Genotyping with a fluorescent primer generates a single dominant peak in wild-type chicken (WT). d A minor peak appears at a position 2-bp shorter than the dominant peak. The ratio of these peaks (X/Y) can be used to estimate the number of alleles with the putative frameshift deletion in a genome (see the Methods section for details). M: 400-bp size marker