Interstitial telomeric signals detected in chromosomes 1 and 2 of C. sativus in this study are likely to be the vestige of the chromosome fusion of two progenitor species.
Tobacco is an allotetraploid (2n = 4 × = 48) derived from the interspecific hybridisation of two progenitor genomes; a maternal 'S' genome, originating from an ancestor of N. sylvestris, and a paternal 'T' genome, most likely originating from a lineage of N. tomentosiformis [ 2- 4].
Recently, the draft genome sequences of two progenitors of bread wheat, Triticum urartu and Aegilops tauschii genomes, have been published [ 3, 4].
When considering two independent hues in a given cell (nucleus and membrane/cytoplasm) and complex patterns only, the theoretical probability of two progenitors to acquire the same hue independently decreases to 1/6×6=0.00005%.
Following 6 days of differentiation up to 40% of the cells expressed CD34 and up to 25% expressed CD43, generated with an average yield of one progenitor per hESC.
The cytological event was first described in Crepis hybrids, when Navashin pointed out morphological changes on a group of chromosomes of one progenitor, detecting the disappearance of their secondary constrictions where rRNA gene arrays are located [11], [12], [19], [20].
The size difference between G1 and G2 nuclei was large enough that in EdU-labeled gonads, G1 and G2 nuclei could be distinguished by eye (n > 100 nuclei, from a total of seven progenitor zones).
While previous studies of Tragopogon allopolyploids showed that homeolog loss is a common consequence of allopoyploidization, here we show that DNA methylation can silence one progenitor homeolog or it can regulate the level of expression of the two progenitor homeologs.
B. napus is an allotetraploid that was generated from the natural hybridization of its two progenitor diploids of Brassica rapa (AA, 2n = 20) and Brassica oleracea (CC, 2n = 18) about 7,500 years ago [ 1, 2].
Using flow cytometry, we estimated the T2 genome to be 1.89-fold larger than the midparent genome (1.84-fold larger than D3 and 1.93-fold larger than D4) or 94.5% of the sum of the two progenitor genomes (supplementary table S4, Supplementary Material online).
Thus, the combined CD34+ cell dose of the two progenitor cell grafts was a median of 17.8 (range 3.6 to 67.5) ×10/kg.
