At the most basic level of inquiry, the percent of a genome derived from TEs, vertebrate genomes can vary from 6 to 60%. If one takes into account aspects of TE diversity, accumulation histories, and even variation in repeat annotations themselves, it becomes difficult to build a coherent narrative that adequately explains repeat variation across vertebrates. Generally, higher levels of TE diversity correlate with the age of vertebrate lineages; lineages that have existed for longer periods, such as fishes, and deep-branching tetrapods tend to have higher TE diversity than more recent radiations, such as birds and mammals. However, as the number of vertebrate genome assemblies increases, exceptions to this pattern will become more common. Known outliers within each vertebrate lineage include the lungfish with a genome dominated by two types of non-LTR retrotransposons, and the western clawed frog whose TE content is highly biased towards DNA transposons. Woodpeckers contain almost half a million more TE copies than other birds. Among mammals, vespertilionid bats is the sole lineage exhibiting DNA transposon activity. Indeed, our view of what is ‘normal’ for broad lineage such as mammals or birds continues to expand and our understanding of TEs and their role in vertebrate genome evolution benefits greatly from understanding both general trends and outliers. Identification of the contribution of TEs to the uniqueness of each genome will be key to unravelling the impact of genome architecture on organismal evolution. [colour emphasis added] Paper. (public access) – Evolution and Diversity of Transposable Elements in Vertebrate Genomes
Cibele G Sotero-Caio Roy N Platt, II Alexander Suh David A Ray Genome Biol Evol (2017) evw264. DOI: https://doi.org/10.1093/gbe/evw264 More.
Note: From the definition of transposons at Nature: “For decades, scientists dismissed transposable elements, also known as transposons or “jumping genes”, as useless ‘junk DNA.’ But are they really?” No. But Darwinism needed that “narrative.”
See also: Jumping genes make the tree of life a bush
Life continues to ignore what evolution experts say
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