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SUBGENOME INEQUALITY. "Once genome dominance is established during the initial inbreeding generations following the polyploidy event itself, genes on one subgenome tend to express less than genes on the other. We predict that this essential inequality begins a cascade of mutational differences based on nothing more profound than “a less expressed gene is easier to mutate” or alter by recombination." https://lnkd.in/bCmw3Fr View in LinkedIn

ANCESTRAL FOOTPRINTS. "This diploidization phenomenon reflects mechanistically diverse processes, operating collectively and over the long haul, ultimately leading to contemporary descendants that behave cytogenetically as normal diploids while harboring in their genomes the vestigial evidence of past polyploidy events." http://www.amjbot.org/content/early/2015/10/09/ajb.1500320 View in LinkedIn

BLOOM AND PURGE. "We hypothesize that when two genomes come together in an allotetraploid, one genome has invariably made compromises to a different level than the other based on differences in transposon bloom-and-purge history and the degree of selection against TE amplification." (TE = transposable element). https://lnkd.in/bCmw3Fr View in LinkedIn

REVERSIBLE POLYPLOIDY. "Thus, it is immediately apparent that polyploidy is, at least in part, reversible, and that over time it is followed by massive chromosomal rearrangements, reductions in chromosome number, and the large-scale loss of both repetitive sequences and duplicated genes all leading to genome downsizing." http://www.amjbot.org/content/early/2015/10/09/ajb.1500320 View in LinkedIn

POSITION EFFECT. "Hollister et al., provided strong evidence that TE silencing represents a tradeoff between the primary selection to reduce transposon expression and the consequent reduction in levels of gene expression for genes near transposons via a position effect whereby the silencing of the transposon spreads to an adjacent gene’s promoter." (TE = transposable element). https://lnkd.in/bCmw3Fr View in LinkedIn

THEORY VS PRACTICE 2. "Similarly, and notwithstanding the uncertainty regarding actual ancestral angiosperm genome sizes, if one postulates a small ancestral genome size of, say, 300 megabases, in the absence of countervailing forces the modern G. hirsutum genome should be enormous, 43.2 gigabases (Gb), instead of the 2.4 Gb that it actually contains." http://www.amjbot.org/content/early/2015/10/09/ajb.1500320 View in LinkedIn

TRANSPOSABLE ELEMENT (TE) LOAD. "Because the two subgenomes of an allotetraploid originate from two different genomes existing tens of millions of years ago, each with what must have been different transposon populations, bloom histories, distributions, and levels, we hypothesize that a differential load of TEs in the parental lines is a sufficient explanation for the origin of subgenome dominance." https://lnkd.in/bCmw3Fr View in LinkedIn

THEORY VS PRACTICE 1. "If one assumes that the ancestral angiosperm chromosome number is 5–7, as often suggested, then modern Gossypium hirsutum, for example, should have 5–7 times 144, or 720–1008 chromosomes in its haploid complement, in the absence of massive, repeated chromosome number reduction, instead of the 26 it actually contains." http://www.amjbot.org/content/early/2015/10/09/ajb.1500320 View in LinkedIn

CONSEQUENCES. "Some of the longer-term consequences of repeated, cyclical polyploidy become evident when one considers that lineages having experienced multiple historical rounds of polyploidy do not exhibit especially high chromosome numbers nor genome sizes." http://www.amjbot.org/content/early/2015/10/09/ajb.1500320 View in LinkedIn

CASCADE OF TRAITS. "Even more varied yet poorly understood is the gamut of short-term evolutionary responses to polyploidy at other “omics” levels, including a diverse suite of epigenomic and small RNA alterations with cascading effects that propagate through proteomic, physiological, and metabolomic networks to ultimately affect plant phenotype and function." http://www.amjbot.org/content/early/2015/10/09/ajb.1500320 View in LinkedIn