The main computations during generations of enTTS signature are addition, multiplication, inversion, and solving Systems of Linear Equations (LSEs) in a finite field.
We found direct evidence for the implication of transposon BuT5 in the generation of inversion 2s and only circumstantial evidence for the implication of the transposons BuT5 and Galileo in inversions 2c and 2r, respectively.
In any case, the generation of inversion 2s by transposon BuT5 is a significant finding because, in Dipterans, the implication of TEs in the generation of chromosomal inversions has been demonstrated for a few polymorphic rearrangements but never for fixed inversions (see Introduction).
These sequences can be interpreted as TSD produced at the time of the transposon insertion and its exchanged arrangement (ACTTGCCTT and CTGTATAAT are the inverted complementary versions of AAGGCAAGT and ATTATACAG, respectively) provides unequivocal evidence for the generation of inversion 2s by ectopic recombination between BuT5 copies.
Instead, the authors found short duplications of nonrepetitive sequence at the breakpoints of most of the inversions they identified and proposed a novel mechanism for the generation of inversions involving staggered single-strand breaks followed by nonhomologous end joining.
This high intraspecific polymorphism for chromosomal inversions and Galileo abundance suggest a role for Galileo in the generation of inversions in D. willistoni and related species.
In Drosophila, the evidence for the implication of TEs in the generation of inversions is limited.
The participation of Galileo in the generation of inversions may be also related to its unusual structure with up to 1.2-kb long TIRs [61], [62].
The accumulation of Galileo copies after the generation of inversions 2j and 2q7 (Table 3) indicates that Galileo is (or has been recently) active in the genome of D. buzzatii.
Finally, no definitive conclusion can be drawn about the generation of inversions 2f and 2g.
