Biology subjects

Pianezza, R.

Publications and source records attributed to Pianezza, R..

4 recordsLinked to original sources

bioRxiv2024

GenomeDelta: detecting recent transposable element invasions without repeat library

To evade repression by the host defense, transposable elements (TEs) are occasionally horizontally transferred (HT) to naive species. TE invasions triggered by HT may be much more abundant than previously thought. For example, previous studies in Drosophila melanogaster found 11 TE invasions over 200 the past years. A major limitation of current approaches for detecting recent invasions is the necessity for a repeat-library, which is notoriously difficult to generate. To address this, we developed GenomeDelta, a novel approach for identifying sample-specific sequences, such as recently invading TEs, without prior knowledge of the sequence. It can thus be used with model and non-model organisms. As input, GenomeDelta requires a long-read assembly and short-read data. It will find sequences in the assembly that are not represented in the short read data. Beyond identifying recent TE invasions, GenomeDelta can detect sequences with spatially heterogeneous distributions, recent insertions of viral elements and recent lateral gene transfers. We thoroughly validated GenomeDelta with simulated and real data from extant and historical specimens. Finally, we demonstrate that GenomeDelta can reveal novel biological insights: we discovered the three most recent TE invasions in Drosophila melanogaster and a novel TE with a geographically heterogeneous distribution in Zymoseptoria tritici.

bioinformatics↗

bioRxiv2024

Unveiling the complete invasion history of D. melanogaster: three horizontal transfers of transposable elements in the last 30 years

Transposable elements (TEs) are repetitive sequences capable of mobilizing within genomes, exerting significant influence on evolution throughout the tree of life. Using a novel approach that does not require prior knowledge about the sequence of repeats, we identified three novel TE invasions in D. melanogaster : MLE spread between 1990-2000, Souslik between 2009-2012, and Transib1 between 2013-2016. We recapitulate prior findings, revealing that a total of 11 TEs invaded D. melanogaster over the past two centuries. Leveraging data from over 1400 arthropod genomes, we provide evidence that the TE invasions were triggered by horizontal transfers, with D. simulans and species of the D. willistoni group acting as putative donors. Through analysis of[~] 600 short-read datasets spanning diverse geographic regions, we reveal the rapidity of TE invasions: Transib1 swiftly multiplied from three isolated epicenters in 2014 to all investigated populations within just two years. Our findings suggest that anthropogenic activities, facilitating habitat and population expansions of D. melanogaster, might have accelerated the rate of horizontal transposon transfer as well the spread of the TEs into the worldwide population. Given the significant impact of TEs in genomes and the potential involvement of humans in their dispersal, our research has crucial implications for both evolution and ecology.

genomics↗

bioRxiv2023

Spoink, a LTR retrotransposon, invaded D. melanogaster populations in the 1990s

During the last few centuries D. melanogaster populations were invaded by several transposable elements, the most recent of which was thought to be the P-element between 1950 and 1980. Here we describe a novel TE, which we named Spoink, that has invaded D. melanogaster. It is a 5216nt LTR retrotransposon of the Ty3/gypsy superfamily. Relying on strains sampled at different times during the last century we show that Spoink invaded worldwide D. melanogaster populations after the P-element between 1983 and 1993. This invasion was likely triggered by a horizontal transfer from the D. willistoni group, much as the P-element. Spoink is probably silenced by the piRNA pathway in natural populations and about 1/3 of the examined strains have an insertion into a canonical piRNA cluster such as 42AB. Given the degree of genetic investigation of D. melanogaster it is surprising that Spoink was able to invade unnoticed.

evolutionary biology↗

bioRxiv2023

Genomes of historical specimens reveal multiple invasions of LTR retrotransposons in Drosophila melanogaster populations during the 19th century.

Transposable element invasions have a profound impact on the evolution of genomes and phenotype. It is thus an important open question on how often such TE invasions occur. Based on strains sampled at different times, previous work showed that four different TE families invaded D. melanogaster during the 20th century. Here we utilize the genomes of historical specimens to extend this work by another 100 years. We found that the LTR retrotransposons Blood, Opus and 412 spread in D. melanogaster in the 19th century. These invasions were found to constitute second waves, as degraded fragments were found for all three TEs. We show that two of the three invasions, Opus and 412, led to pronounced geographic heterogeneity, likely due to founder effects during the invasions. Finally, we identified species from the simulans complex as the likely origin of the TEs. In total, seven TE families invaded D. melanogaster during the last 200 years, increasing the genome size by 1.2 Mbp. Based on the analysis of strains and specimens sampled at different times, we provide a detailed timeline of TE invasions, making D. melanogaster the first organism where we could infer the invasion history of TEs during the last two centuries.

evolutionary biology↗