After reading the paper[1], AFAICT the phenotype results can also be explained by selecting for pre-existing mutants (the cells of the embryo containing the targeted sequence are killed off) followed by transvection[2]. They assume a simple dominant-recessive relationship between alleles of the yellow gene and pigmentation, which is not true[3]. Also, the primers they used for PCR shown in Fig 2D don&#x27;t look like they span the genome-insertion junction...<p>[1] <a href="http:&#x2F;&#x2F;www.sciencemag.org&#x2F;content&#x2F;348&#x2F;6233&#x2F;442" rel="nofollow">http:&#x2F;&#x2F;www.sciencemag.org&#x2F;content&#x2F;348&#x2F;6233&#x2F;442</a><p>[2] <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Transvection_%28genetics%29" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Transvection_%28genetics%29</a><p>[3] <a href="http:&#x2F;&#x2F;www.ncbi.nlm.nih.gov&#x2F;pmc&#x2F;articles&#x2F;PMC2766311&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.ncbi.nlm.nih.gov&#x2F;pmc&#x2F;articles&#x2F;PMC2766311&#x2F;</a>