Fig. 6
From: Asynapsis and unreduced gamete formation in a Trifolium interspecific hybrid
Meiosis (pachytene to metaphase II) in hybrids 33OP-1 (left column) and 33OP-14 (right column). a-d. Pachytene cells after DAPI staining (a, c) and the same cells after FISH (b, d). In a and c the arrows show irregular synapsis. In b, NOR-carrying chromosomes from T. ambiguum (arrow) and from T. occidentale and T. repens (arrowhead) form separate trivalents. In d the arrow indicates multivalent formation involving NOR chromosomes from both parental genomes. e-h. Metaphase I cells after DAPI staining (e, g) and the same cells after FISH (f, h). Arrows in e indicate abnormal pairing of marker chromosomes visible in f. The arrow in g indicates a nonhomologous multivalent involving the T. occidentale NOR chromosome (arrow in h). i-l. Anaphase I cells after DAPI staining (i, k) and the same cells after FISH (j, l) showing several laggards, including precociously separated sister chromatids (arrows) and chromosomal fragments (arrowheads). m-p. Metaphase II cells after DAPI staining (m, o) and the same cells after FISH (n, p) with sister chromatid laggards (arrows in m, o). Scale bar: 10 μm