Preferential elimination of repeated DNA sequences from the paternal, Nicotiana tomentosiformis genome donor of a synthetic, allotetraploid tobacco.

摘要: Summary • Nicotiana tabacum (tobacco, 2n = 4x = 48) is a natural allotetraploid combining two ancestral genomes closely related to modern Nicotiana sylvestris and tomentosiformis. Here we examine the immediate consequences of allopolyploidy on genome evolution using 20 S4-generation plants derived from single synthetic, S0 plant made by Burk in 1973 (Th37). • Using molecular cytogenetic methods analysed 14 middle highly repetitive sequences that together total ≈ 4% genome. • Two repeats endogenous geminiviruses (GRD5) pararetroviruses (NtoEPRV), classes satellite (NTRS, A1/A2) were partially or completely eliminated at variable frequency (25–60%). These are all N. tomentosiformis parent. Genomic situ hybridization revealed additivity chromosome numbers (2n = 48), while third was aneuploid for an N. tomentosiformis-origin (2n = 49). Two had homozygous translocations between chromosomes S- T-genomes. • The data demonstrate genetic changes synthetic tobacco fast, targeted paternal N. tomentosiformis-donated genome, some showed concordance with presumably occurred during tobacco.