Further evidence for a heterochromatin-chiasma correlation in some Allium species

Even in cases in which C-bands are intercalary in chromosomes of Allium carinatum and A. flavum. chiasmata are formed in immediately adjacent regions. This argues against considerations that there exists merely a spatial proximity between the commonly found distal chiasmata and the C-bands in corresponding regions, without any causal relation. Furthermore, a closely related species, A. sipyleum, without distinctly visible C-bands has a much less localized chiasma distribution in its bivalents.