Papal cross Papal cross The papal cross is a Christian cross, which serves as an emblem for the office of the Pope in ecclesiastical heraldry. It is depicted as a staff with three horizontal bars near the top, in diminishing order of length as the top is approached. The cross is thus analogous to the two-barred archiepiscopal cross used in heraldry to indicate an archbishop, and seems to have been used precisely to indicate an ecclesiastical rank still higher than that of archbishop. In the past, this design of the cross was often used in ecclesiastical heraldry as a distinctive mark of
Plant–fungus horizontal gene transfer ancient, they have been difficult to detect and remain relatively unknown. Plant–fungus interactions could play a part in a multi-horizontal gene transfer pathway among many other organisms. Fungus–plant-mediated horizontal gene transfer can occur via phagotrophic mechanisms (mediated by phagotrophic eukaryotes) and nonphagotropic mechanisms. Nonphagotrophic mechanisms have been seen in the transmission of transposable elements, plastid-derived endosymbiotic gene transfer, prokaryote-derived gene transfer, "Agrobacterium tumefaciens"-mediated DNA transfer, cross-species hybridization events, and gene transfer between mitochondrial genes. Horizontal gene transfer could bypass eukaryotic barrier features like linear chromatin-based chromosomes, intron–exon gene structures, and the nuclear envelope. Horizontal gene transfer occurs between microorganisms sharing