Synaptonemal complex of the F1 hybrids of maize x perennial teosinte

Anthers of the F1 hybrids of maize x perennial teosinte were studied by following the techniques of electron microscopy previously employed by the author (Ting, Chromosomes Today 4, 1973). At pachytene stage it was consistently observed that synaptonemal complex was present. The characteristics of the complex resemble those of both haploid and diploid maize. For instance its diameter, on the average, measured 2200 Å. The three components (two lateral elements and one central element) were discernible. All of them appeared bipartite in organization. No cross-fibers between central and lateral elements were definitely identified. Furthermore it was impossible to distinguish the complexes formed by autosyndesis (teosinte chromosomes synapsed with teosinte chromosomes) from those formed by allosyndesis (teosinte chromosomes synapsed with maize chromosomes). However, contact between the complex and the nuclear envelope was not observed. On several occasions, isolated chromosome cores were found and they are apparently from unpaired chromosomes, either from maize or from teosinte. From diplotene stage to diakinesis, as in both haploid and diploid maize, the complexes gradually disorganized. It seems that this observation provides another evidence that maize and teosinte should be congeneric.

Y. C. Ting

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