Do the different parental 'heteromes' cause genomic shock in newly formed allopolyploids?
Allopolyploidy, the joining of two parental genomes in a polyploid organism with diploid meiosis, is an important mechanism of reticulate evolution. While many successful long-established allopolyploids are known, those formed recently undergo an instability phase whose basis is now being characterized. We describe observations made with the Arabidopsis system that include phenotypic instability, gene silencing and activation, and methylation changes. We present a model based on the epigenetic destabilization of genomic repeats, which in the parents are heterochromatinized and suppressed. We hypothesize that loss of epigenetic suppression of these sequences, here defined as the heterome, results in genomic instability including silencing of single-copy genes.
Comai
Luca
L
Department of Biology, Box 355325, University of Washington, Seattle, WA 98195-5325, USA. comai@u.washington.edu
Madlung
Andreas
A
Josefsson
Caroline
C
Tyagi
Anand
A
D017360:Arabidopsis / Q000235:genetics*; D019175:DNA Methylation; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D017343:Genes, Plant / Q000235:genetics; D018745:Genome, Plant; D006570:Heterochromatin / Q000235:genetics*; D008957:Models, Genetic; D010641:Phenotype; D011123:Polyploidy
D006570:Heterochromatin