Chromosome Rearrangements and Transposable Elements

Abstract

There has been limited corroboration to date for McClintock's vision of gene regulation by transposable elements (TEs), although her proposition on the origin of species by TE-induced complex chromosome reorganizations in combination with gene mutations, i.e., the involvement of both factors in relatively sudden formations of species in many plant and animal genera, has been more promising. Moreover, resolution is in sight for several seemingly contradictory phenomena such as the endless reshuffling of chromosome structures and gene sequences versus synteny and the constancy of living fossils (or stasis in general). Recent wide-ranging investigations have confirmed and enlarged the number of earlier cases of TE target site selection (hot spots for TE integration), implying preestablished rather than accidental chromosome rearrangements for nonhomologous recombination of host DNA. The possibility of a partly predetermined generation of biodiversity and new species is discussed. The views of several leading transposon experts on the rather abrupt origin of new species have not been synthesized into the macroevolutionary theory of the punctuated equilibrium school of paleontology inferred from thoroughly consistent features of the fossil record.

How life changes itself: The Read–Write (RW) genome

“…Chromosome rearrangements are important in taxonomic divergence because they affect both genome expression and set up meiotic barriers to interbreeding. In some cases we can link chromosome rearrangements to the presence of mobile elements [250], where they may act either as sources of dispersed homology for recombinational exchange [251] or as active agents of chromosome breakage and rejoining [252,253].…”

Repetitive DNA in the automictic fungus Microbotryum violaceum

“…The clearest evidence comes from the proportion of nuclear DNA that is made up of transposable elements, which in many plants and animals is greater than a third of all sequences (Kidwell, 2002). There are also large costs to carrying transposable elements because their insertion throughout the genomes can disrupt the expression of functional genes (Casacuberta & Santiago, 2003) and leads to chromosomal rearrangements between elements at non-homologous sites (Lo¨nnig & Saedler, 2002;Shnyreva, 2003). Eukaryotic systems have in turn evolved resistance mechanisms to protect against these mutating effects, and in some cases may have co-opted repetitive elements that now perform beneficial roles as regulatory or structural sequences (Kidwell & Lisch, 2001;Hurst & Werren, 2001).…”

Toward closing rice telomere gaps: mapping and sequence characterization of rice subtelomere regions

“…Polymorphic subtelomere regions have been shown to serve as hot spots for the nested insertion of non-LTR retroelements, such as long interspersed nucleotide elements (LINEs) and short interspersed nucleotide elements (SINEs), as in the Trypanosoma brucei (Bringaud et al 2002) and Chlorella genomes (Higashiyama et al 1997;Noutoshi et al 1998). The accumulation of transposable elements in subtelomere regions has been postulated to account for both chromosome stability and genome rearrangements (Zhang and Peterson 1999;Bringaud et al 2002;Lonnig and Saedler 2002;Barry et al 2003). FISH analyses using telomere clones Tel10S and Tel7L revealed strong Fig.…”

“…The TATRs are interrupted by subsequent insertions of retrotransposons or transposable elements. Transposons are able to mediate large-scale genome reorganization by virtue of their ability to induce chromosomal rearrangements such as deletions, duplications, inversions, reciprocal translocations (reviewed in Zhang and Peterson 1999;Lonnig and Saedler 2002), and small-scale gene evolution (Song et al 1998;Witte et al 2001;Bringaud et al 2002). The TATR7 sequences appear to be located at both ends of chromosome 7 and seem to be dispersed in the large region because it is interrupted by other transposons.…”