Domesticated P elements in the Drosophila montium species subgroup have   a new function related to a DNA binding property
  Molecular domestication of a transposable element is defined as its functional recruitment by the host genome. To date, two independent events of molecular domestication of the P transposable element have been described: in the Drosophila obscura species group and in the Drosophila montium species subgroup. These P neogenes consist to stationary, non repeated sequences, potentially encoding 66 kDa repressor-like proteins (RLs). Here we investigate the function of the montium P neogenes. We provide evidence for the presence of RLs proteins in two montium species (D. tsacasi and D. bocqueti) specifically expressed in adult and larval brain and gonads. We tested the hypothesis that the montium P neogenes function is related to the repression of the transposition of distant related mobile P elements which coexist in the genome. Our results strongly suggest that the montium P neogenes are not recruited to down regulate the P element transposition. Given that all the proteins encoded by mobile or stationary P homologous sequences show a strong conservation of the DNA Binding Domain, we tested the capacity of the RLs proteins to bind DNA in vivo. Immunstaining of polytene chromosomes in D. melanogaster transgenic lines strongly suggest that montium P neogenes encode proteins that bind DNA in vivo. RLs proteins show multiple binding to the chromosomes. We suggest that the property recruited in the case of the montium P neoproteins is their DNA binding property. The possible functions of these neogenes are discussed. 
Daphn\'e Reiss (IJM), Danielle Nouaud (IJM), St\'ephane Ronsseray   (IJM), Dominique Anxolab\'eh\`ere (IJM)