Population genetics of transposable element load: A mechanistic account of observed overdispersion

In an empirical analysis of transposable element (TE) abundance within natural populations of Mimulus guttatus and Drosophila melanogaster, we found a surprisingly high variance of TE count (e.g., variance-to-mean ratio on the order of 10 to 300). To obtain insight regarding the evolutionary genetic...

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Bibliographic Details
Published in:PloS one 2022-07, Vol.17 (7), p.e0270839-e0270839
Main Authors: Smith, Ronald D, Puzey, Joshua R, Conradi Smith, Gregory D
Format: Article
Language:English
Subjects:
Abundance
Analysis
Biology and Life Sciences
Computer simulation
Demography
Empirical analysis
Engineering and Technology
Equilibrium
Genetics
Genomes
Load
Markov processes
Mathematical models
Natural populations
Population genetics
Research and Analysis Methods
Transposons
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Summary:In an empirical analysis of transposable element (TE) abundance within natural populations of Mimulus guttatus and Drosophila melanogaster, we found a surprisingly high variance of TE count (e.g., variance-to-mean ratio on the order of 10 to 300). To obtain insight regarding the evolutionary genetic mechanisms that underlie the overdispersed population distributions of TE abundance, we developed a mathematical model of TE population genetics that includes the dynamics of element proliferation and purifying selection on TE load. The modeling approach begins with a master equation for a birth-death process and extends the predictions of the classical theory of TE dynamics in several ways. In particular, moment-based analyses of population distributions of TE load reveal that overdispersion is likely to arise via copy-and-paste proliferation dynamics, especially when the elementary processes of proliferation and excision are approximately balanced. Parameter studies and analytic work confirm this result and further suggest that overdispersed population distributions of TE abundance are probably not a consequence of purifying selection on total element load.
ISSN:1932-6203
1932-6203
DOI:10.1371/journal.pone.0270839