More specifically, we observed two bivalents with two chiasmata
in five diplotene nuclei and one bivalent with three chiasmata
in five diplotene nuclei.
the number of chiasmata, and the larger structural rearrangements (e.
the reciprocal exchange of parts of the chromatids of the homologous chromosomes - can take place, and it ensures that bivalents are formed from the homologous parental chromosomes and are held together by chiasmata until first meiotic division.
At this point is should be noted that the mathematical models as well as all other calculations and interpretations in genome analysis are based on observations of chiasmata, although the claim is that these observations represent an estimate of pairing (and similarity) along the entire length of the chromosomes (e.
In addition, however, it needs to be stressed that both processes must have profound influences on genetic recombination and segregation by changing the number and nature of linkage groups (interchromosome modification), while the known marked differences in frequency and distribution of chiasmata in metacentrics as compared with acro- or telocentrics (Mattsson, 1971; Bideau, 1990, 1993) should result in different patterns of intrachromosome recombination.
standleyi is 2n = 16 (12 M + 4 t) and forms bivalents only, but with highly proximal chiasmata inhibiting any potential multivalent formation.
During late prophase I, all bivalents presented a ring shape, evidencing two chiasmata per bivalent.
All bivalents present a ring shape, evidencing the occurrence of two terminal chiasmata per bivalent, and the X chromosome constitutes an univalent during all meiosis I (Fig.