Transposon-mediated genic rearrangements underlie variation in small RNA pathways

Transposable elements (TEs) can alter host gene structure and expression, whereas host organisms develop mechanisms to repress TE activities. In the nematode Caenorhabditis elegans, a small interfering RNA pathway dependent on the helicase ERI-6/7 primarily silences retrotransposons and recent genes of likely viral origin. By studying gene expression variation among wild C. elegans strains, we found that structural variants and transposon remnants likely underlie expression variation in eri-6/7 and the pathway targets. We further found that multiple insertions of the DNA transposons, Polintons, reshuffled the eri-6/7 locus and induced inversion of eri-6 in some wild strains. In the inverted configuration, gene function was previously shown to be repaired by unusual trans-splicing mediated by direct repeats. We identified that these direct repeats originated from terminal inverted repeats of Polintons. Our findings highlight the role of host-transposon interactions in driving rapid host genome diversification among natural populations and shed light on evolutionary novelty in genes and splicing mechanisms.

Revealing a key mechanism of rapid centromere evolution

A joint research group team led by Sayuri Tsukahara and Tetsuji Kakutani of the University of Tokyo has clarified a mechanism of how retrotransposons, genetic elements that can “jump around” chromosomes and are known drivers of evolution, preferentially insert in the centromere. The findings were published in the journal Nature.

Detection and classification of long terminal repeat sequences in plant LTR-retrotransposons and their analysis using explainable machine learning

Research unravels the enigma of curly birch and suggests marker to recognize it at the sprout stage

Curly—or Karelian—birch is a mysterious tree with a patterned wood texture and a bizarre trunk shape. Unlike the elegant white-stemmed traditional birch, the Karelian one may seem unsightly at first glance: It is a low-growing, sinuous tree with bumps and bubbles. But the Karelian birch is famous for its wood. With its beautiful shade, patterns, and durability, the material has been used since the XVIII century in the manufacture of furniture, even for the royal chambers. For this reason, the Karelian birch was called the "royal tree" and "wooden marble."

Defense against the enemy within

Defense against the enemy within