Fig. 2.
The Mek1Y130C allele contains a partial duplication of the Mek1 gene. (A) Schematic of the endogenous Mek1 gene, the Mek1Y130C allele and the Mek1 null allele with the expected DNA fragments after StuI digestion and detection with probe b. (B) Southern blot analysis of tail DNA from a litter obtained following Mek1+/−×Mek1+/Y130C breeding. DNA was digested with StuI, blotted and hybridized with probe b. Mice positive for the Mek1Y130C allele always carried a wt allele even when a null allele was detected. The wt allele showed a stronger signal equivalent to the one of wt mice, suggesting Mek1 gene duplication in the Mek1Y130C allele. (C) Whole-genome sequencing alignment reveals a 61.5 kb Mek1 duplication starting 6.5 kb upstream of the Mek1 transcription start site and ending in the fifth intron. Only one break point was observed between the fifth intron in 5′ and Mek1 promoter sequences in 3′, suggesting intragenic duplication occurring by unequal crossing over.