The element invaded rapidly and caused hybrid dysgenesis in natural populations of in Japan.

Transposable elements not only can change genomic positions and disperse across the gene pool, but also can jump to another species through horizontal transmission. Of late, the element, a DNA transposon in insects, was shown to cross the genetic boundary from to in Europe around 2006. To understand the dynamics of transposable elements, especially in the early stages of invasion, we examined 63 lines of from 11 natural populations in Japan established in 1976-2015. Based on PCR analyses, elements were demonstrated to exist in Japan in 2008 and later. One copy of the full-length element was identified and mapped to a site on chromosome 3 L in a genome. All of 18 copies of elements examined shared "A" at the nucleotide position 2040, which is representative of the direct descendants of the original element that invaded in . We also found that some lines having elements can induce intensive gonadal dysgenesis in at 29°C. Our present results imply that elements in arrived at the east end of Asia just a few years later than or almost simultaneously to the initial invasion in Europe, Africa, and North America, suggesting a more astonishingly rapid spread than previously assumed.