A RetroSearch Logo

Home - News ( United States | United Kingdom | Italy | Germany ) - Football scores

Search Query:

Showing content from https://link.springer.com/doi/10.1007/BF00321061 below:

Whole mount electron microscopy of meiotic chromosomes and the synaptonemal complex

Abstract

The mechanism by which homologous chromosomes pair and crossover has been a major unsolved problem in genetics. Thin section electron microscopy of the synaptonemal complex has not provided enough details to allow any significant insight into this problem. Whole mount preparations of the testis of mice, quail, crayfish, and frogs provided a striking improvement in visualization of the morphological features of meiotic chromosomes. These studies, when combined with the use of deoxyribonuclease and trypsin allowed the following conclusions. 1. The synaptonemal complex (lateral and central elements with connecting L-C fibers) is composed of protein. 2. Contrary to common speculation the central element is not the pairing surface of homologous chromosomes. 3. The L-C fibers, averaging 75–100 Å in width, extend from the lateral elements and meet to form the central element which is usually composed of four fibers. 4. During leptotene, homologous axial elements, although unpaired for most of their length, attach next to each other at the nuclear membrane. 5. Short segments of the chromatin fibers attach to the lateral elements. These points of attachment are clustered, producing the chromomeres seen by light microscopy. 6. The chromatin fibers extend out from the lateral element as loops. Lampbrush chromosomes are thus not restricted to oogenesis but are common to all meiotic chromosomes.

Since the morphological features of the central element of the synaptonemal complex persist despite extensive deoxyribonuclease digestion, pairing is perhaps best visualized as a two-step process consisting of a) chromosomal pairing during which the proteinaceous synaptonemal complex pulls homologous chromosomes into approximate association with each other, and b) molecular pairing, which probably takes place in the area around the synaptonemal complex.

This is a preview of subscription content, log in via an institution to check access.

Access this article Subscribe and save

Springer+ Basic

€34.99 /Month

Subscribe now Buy Now

Price includes VAT (Germany)

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others Explore related subjectsDiscover the latest articles and news from researchers in related subjects, suggested using machine learning. References

Download references

Author information Authors and Affiliations
  1. Department of Medical Genetics, City of Hope Medical Center, Duarte, California

    David E. Comings & Tadashi A. Okada

Authors
  1. David E. Comings
  2. Tadashi A. Okada
Additional information

Supported by NIH Grants GM-15886 and C-2568, and The Charles and Henrietta Detoy Research Fellowship.

About this article Cite this article

Comings, D.E., Okada, T.A. Whole mount electron microscopy of meiotic chromosomes and the synaptonemal complex. Chromosoma 30, 269–286 (1970). https://doi.org/10.1007/BF00321061

Download citation

Keywords

RetroSearch is an open source project built by @garambo | Open a GitHub Issue

Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo

HTML: 3.2 | Encoding: UTF-8 | Version: 0.7.4