Unlike the M type, the splicing of O-type transcripts in D.bifasciata follows the classical rules of tissue-specific P element regulation: transposase mRNA is produced exclusively in the germline, whereas repressor mRNA is formed in somatic cells. Thus O-type elements are thought to be transpositionally active in this species.
Two distinct P-element subfamilies, designated M-type and O-type, reside in the D.bifasciata genome. Outside the genus O-type elements are detected in S.pallida. Restriction analysis demonstrates the general structure of the O-type elements from S.pallida and D.bifasciata is the same, sequence divergence is very low. Results suggest that the O-type element of D.bifasciata has been received by horizontal transfer from an external source, as is previously suspected for the M-type family. Sequence analysis of the M-type elements demonstrates two independent intergenic transfer events must have occurred.
The genome of D.bifasciata harbours two distinct subfamilies of P-homologous sequences, designated M-type and O-type elements based on similarities to P-element sequences from other species. M-type and O-type elements have no common origin in the D.bifasciata lineage. M-type sequence is most closely related to the P-element from S.pallida, the origin of O-type elements cannot be deduced.
M-type and O-type elements have no common origin in the D.bifasciata lineage. M-type sequence is most closely related to the P-element from S.pallida; the origin of O-type elements cannot be deduced.
Transposable elements (TEs) from D.melanogaster are also found in species of the obscura group. Dbif\P-element shows close sequence similarity to the D.melanogaster homolog.
Unlike the M type, the splicing of O-type transcripts in D.bifasciata follows the classical rules of tissue-specific P element regulation: transposase mRNA is produced exclusively in the germline, whereas repressor mRNA is formed in somatic cells. Thus O-type elements are thought to be transpositionally active in this species.
Two distinct P-element subfamilies, designated M-type and O-type, reside in the D.bifasciata genome. Outside the genus O-type elements are detected in S.pallida. Restriction analysis demonstrates the general structure of the O-type elements from S.pallida and D.bifasciata is the same, sequence divergence is very low. Results suggest that the O-type element of D.bifasciata has been received by horizontal transfer from an external source, as is previously suspected for the M-type family. Sequence analysis of the M-type elements demonstrates two independent intergenic transfer events must have occurred.
The genome of D.bifasciata harbours two distinct subfamilies of P-homologous sequences, designated M-type and O-type elements based on similarities to P-element sequences from other species. M-type and O-type elements have no common origin in the D.bifasciata lineage. M-type sequence is most closely related to the P-element from S.pallida, the origin of O-type elements cannot be deduced.
M-type and O-type elements have no common origin in the D.bifasciata lineage. M-type sequence is most closely related to the P-element from S.pallida; the origin of O-type elements cannot be deduced.
Transposable elements (TEs) from D.melanogaster are also found in species of the obscura group. Dbif\P-element shows close sequence similarity to the D.melanogaster homolog.
Internally deleted elements described; not classified as M-type or O-type.