Nj. Besansky et al., PEGASUS, A SMALL TERMINAL INVERTED REPEAT TRANSPOSABLE ELEMENT FOUND IN THE WHITE GENE OF ANOPHELES-GAMBIAE, Genetica, 98(2), 1996, pp. 119-129
Pegasus, a novel transposable element, was discovered as a length poly
morphism in the white gene of Anopheles gambiae. Sequence analysis rev
ealed that this 535 bp element was flanked by 8 bp target site duplica
tions and 8 bp perfect terminal inverted repeats similar to those foun
d in many members of the Tc1 family. Its small size and lack of long o
pen reading frames preclude protein coding capacity. Southern analysis
and in situ hybridization to polytene chromosomes demonstrated that P
egasus occurs in approximately 30 copies in the genomes of An. gambiae
and its sibling species and is homogenous in structure but polymorphi
c in chromosomal location. Characterization of five additional element
s by sequencing revealed nucleotide identities of 95% to 99%. Of 30 Pe
gasus-containing phage crones examined by PCR, only one contained an e
lement exceeding 535 bp in length, due to the insertion of another tra
nsposable element-like sequence. Thus, the majority, if not all, extan
t Pegasus elements may be defective copies of a complete element whose
contemporary existence in An. gambiae is uncertain. No Pegasus-hybrid
izing sequences were detected in nine other anophelines and three culi
cines examined, suggesting a very limited taxonomic distribution.