| Autor: |
Qi, L., Sybenga, J., Jong, J. |
| Zdroj: |
Chromosoma; 1988, Vol. 97 Issue 1, p88-95, 8p |
| Abstrakt: |
The synaptonemal complexes in pollen mother cells (PMCs) of rye in which one chromosome 1R was replaced by the two corresponding telocentrics, and where one additional telocentric 1RS was present, showed approximately the expected 2∶1 ratio of 1R-1RL-1RS trivalent with 1RS univalent versus heteromorphic 1R-1RL bivalent with 1RS bivalent. In addition, however, many cells with a partner exchange were found, several even including bivalents other than 1R. At metaphase I1R-1RL-1RS trivalents predominated, cells with two univalent telocentrics were relatively frequent but partner exchange configurations were extremely rare. It is concluded that the almost consistent failure to form chiasmata in the interstitial region of 1RS after partner exchange, combined with much more frequent chiasma formation in the terminal segment, is the main reason for the unexpected metaphase I configuration frequencies. Possible causes are discussed. The shift observed does not yet explain the erratic variation in relative frequencies of metaphase I configurations reported earlier in similar material. Frequent pairing partner exchange may play a role there also. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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