Trivalent configurations at diakinesis
, and their nearly balanced disjunction, as evident from the MII counts, support this hypothesis.
The chromosomes in precocious migration in metaphases I may have originated from univalents in diakinesis
or have been a result of precocious terminalization of chiasma and the late terminalization of these chiasmas makes the laggard chromosomes in anaphase I (SOUZA-KANESHIMA et al., 2010).
The chromosome pairing, analyzed at diakinesis
stage of meiosis, was primarily bivalent in all hybrids (Fig.
Presence of the trivalent/univalent configuration at diakinesis
suggests that either complete quadrivalent configurations were not attained, or that synapsis of the medial acrocentric element was sufficiently delayed such that crossing over did not occur between the metacentric and the medial acrocentric elements in these cells.
Cytogenetic analyses reveal formation of multivalents at diakinesis
, in the polyploid species like P pseudo-orientale and in its hybrids with diploid species.
grossum surfacespread spermatocytes reaffirmed the correlation previously found between the extent of synapsis at "pachytene" and the localization of chiasmata at diplotene, diakinesis
and metaphase I (Fletcher 1977, Wallace & Jones 1978).
In meiocytes with one B chromosome, they (chromosomes) appear as univalent in diakinesis
and metaphases I; when in number of two, they form bivalents.
Fan and Tai (1985) reported high frequencies (14.7 and 61.9%) of PMCs with a trivalent configuration at diakinesis
in two monosomics in rapeseed (Brassica napus L., 2n = 4x = 38).
Meiotic analyses of C-banded diakinesis
and metaphase I configurations from a variety of Peromyscus species, including three (P.
The meiotic analysis of Aster squamatus showed 10 chromosomes in bivalent associations (II) in diakinesis
and metaphase 1 (Figure 1a), normal chromosomal segregation in anaphase 1 (Figure1b) and telophase 1, and retarding chromosomes in telophase II (Figure 1c), as well as cells with 3 poles (Table 1), and one cell with 5 (Figure 1d).
anaphase backcross diakinesis
segregate translocation mutation allele sequence phenotype locus oligonucleotide prophase chromomere nucleus meiosis pedigree replicon zygote genotype exonuclease cytogenetics codominance nucleolus Metric System decimeter quintal microgram dekagram teragram meter terameter megaliter milligram hectokilogram micrometer kilometer centiliter hectometer gram decimilligram kilogram nanometer liter microliter nanogram decigram gigagram centimeter gigameter kiloliter dekaliter picogram centigram megagram millimeter megameter deciliter centimilligram hectogram picometer dekameter picoliter teraliter