Fragmentaciones cromosómicas en la meiosis del híbridos de Turnara ulmifolia (Turnaracea)

Abstract

The hybrids of T. ulmifolia with other polyploid species show fragmented chromosomes from diplotene/diakinesis to telophase II. The number of fragments is variable, ranging from some few to more than 500, in some cases all the chromosomes are fractured. In most hybrids with fragments, were also observed bridges in anaphase I and anaphase II. The hybrids of T. ulmifolia with diploid species frequently have cells without chromosome fragments, but when present they are few, no more than 5. The DNA is usually fractured in the crossing-over, but the number of fragments is greater than the number of produced chismata. The fragments observed in T. ulmifolia hybrids would be produced by an error in the DNA reparation after the normal breaks at pachitene. This error could be produced by interaction of one genome or chromosome of T. ulmifolia with the remaining species.