1. The 2 bases forming each rung of the 'ladder' snap apart. This is caused by an enzyme that passes along the strands, 'unzipping' it
2. Spare nucleotides (in the nucleus of the cell) attach themselves to the 'broken rungs' to repair the break. Each repairing nucleotide is identical to the broken one
3. As each 'broken rung' is repaired, two 'ladders' form, that is 2 identical strands of DNA. The 'repairing' is really the process of replica
You're crossing the genotype SS with the genotype ss, so you get four boxes with the genotype Ss. This represents 4 wire-haired dogs since wire hair is dominant to the smooth. The recessive allele is not expressed; this is also known as <em>complete dominance</em>. The 'S' allele produced enough proteins for the trait to be expressed in phenotypic form.
