To identify regions of colinearity, the program WABA [ 20] was used to produce base level alignments, followed by merging of adjacent blocks and bridging of small transpositions and inversions.
Long-range LD could be an artefact resulting from mis-assembly or mis-mapping – small-scale transpositions and duplications, or simply because the Xiphophorus maculates genome as a typical next gen draft might have erroneous linkages.
Is this small detail and transposition merely accidental?
The simulations with three models described above (all inversions, a small fraction of transpositions, and equal inversions and transpositions) all yielded a large decrease in clustering as expected (the observed Cf in C. reinhardtii is 0.03397, and the 95% confidence intervals for Cf in simulated genomes were 0.00744 0.01401, 0.00812 0.014299 and 0.0750-0.01418, respectively).
It has been suggested that small inversions and transpositions can be regarded as noise in genome rearrangements [ 27].
The chapter focuses on a matrix transposition, a small and self-contained workload of great practical value.
This would be consistent with movement of small sequence segments via transposition or differential inheritance of paralogous duplications that were present in the last common ancestral genome.
In other words, large genomes would result from large, recent bursts of transposition, whereas small ones would be devoid of any trace of such amplification.
The final result might not be very different from the result of syntenic analysis in simple cases, but this method is more powerful if the genomes contain many small changes such as transposition, inversion, insertions/deletions (indels), and horizontal gene transfers.
Only a small percentage of the transpositions function as protein traps, because the insertion must be within the intron between two protein-coding exons, as well as being in the right orientation and reading frame to create an in-frame protein fusion when the artificial exon is spliced into the mRNA of the inserted gene.
