Month: September 2022

CRITICAL QUESTIONS. "These observations raise the two central questions of this thesis. First, why are TEs so common, and the genomes so large, in some species but not others? Second, what prevents TEs from completely taking over and causing genomes to fail to produce functional individual organisms?" (TE = transposable elements). https://tspace.library.utoronto.ca/handle/1807/70840 View in LinkedIn

RICH SOURCE OF VARIATION. "Transposable elements (TEs) are a major source of genome variation across the branches of life." https://lnkd.in/drMDPh6 View in LinkedIn

MOSTLY NEGATIVE. "Although TEs may occasionally play an adaptive role in their host's genome, they are much more often deleterious, and purifying selection is thus an important factor controlling genomic TE loads." (TE = transposable elements). https://lnkd.in/drMDPh6 View in LinkedIn

PURIFYING SELECTION. "In natural selection, negative selection or purifying selection is the selective removal of alleles that are deleterious. This can result in stabilizing selection through the purging of deleterious variations that arise. Purging of deleterious alleles can be achieved on the population genetics level, with as little as a single point mutation being the unit of selection. In such a case, carriers of the harmful point mutation have fewer offspring each generation, reducing the frequency of the mutation in the gene pool." https://en.m.wikipedia.org/wiki/Negative_selection_(natural_selection) View in LinkedIn

PARASITE DISPARITY. "In contrast, life history and genomic characteristics such as mating system, parasitism, GC content, and RNAi pathways, have been suggested to account for the startling disparity of TE loads in different species." (TE = transposable elements). https://lnkd.in/drMDPh6 View in LinkedIn

VAST SAMPLE. "Here we explicitly test the long term determinants of TE evolution by comparing 42 nematode genomes that span over 500 million years of diversification, and include numerous transitions between life history states and RNAi pathways." (TE = transposable elements). https://lnkd.in/drMDPh6 View in LinkedIn

DOMINANT PURIFYING SELECTION. "We show that purifying selection against TEs is the dominant force throughout the evolutionary history of Nematoda, as indicated by reconstructed ancestral TE loads, and that strong stochastic Ornstein-Uhlenbeck processes are the underlying models which best explain TE diversification among extant species." (TE = transposable elements). https://lnkd.in/drMDPh6 View in LinkedIn

"THE STAGGERING evolutionary success of TEs in eukaryotes is often attributed to their ability to out replicate the host genomes in which they reside, as opposed to any selective advantage that they might provide to their hosts." (TE = transposable elements). https://lnkd.in/dwuaM5f View in LinkedIn

AGAINST THE ODDS. "It has been shown that TEs can spread within and among genomes even in the face of a selective cost to the host." (TE = transposable elements). https://lnkd.in/dwuaM5f View in LinkedIn

"THE SELFISH DNA concept of TEs focuses on the parasitic nature of these elements and emphasizes the deleterious effects of transposition as well as the negligible evolutionary benefit that TEs provide to their hosts." (TE = transposable elements). https://lnkd.in/dwuaM5f View in LinkedIn