Recombination of mitochondrial DNA without selection pressure among compatible strains of the Aspergillus niger species aggregate |
| |
Authors: | Beáta Tóth Zsuzsanna Hamari Lajos Ferenczy János Varga F Kevei |
| |
Institution: | (1) Department of Microbiology, Attila József University, H-6701 Szeged, P. O. Box 533, Hungary Fax: (36)(62)432-488 e-mail: kevei@bio.u-szeged.hu, HU;(2) Microbiological Research Group of Hungarian Academy of Sciences, H-6701 Szeged, P. O. Box 533, Hungary, HU |
| |
Abstract: | Previous mitochondrial transmission experiments between oligomycin-resistant and oligomycin-sensitive incompatible strains
of the A. niger aggregate bearing various mtDNA RFLP profiles resulted in a great variety of mitochondrial recombinants under selection pressure.
Apart from the recombinant mtDNAs, resistant clones harbouring unchanged RFLP profiles of resistant donor mtDNAs with the
recipient nuclear backgrounds were rarely isolated. These strains were anastomosed with nuclearly isogenic oligomycin-sensitive
recipient partners and the mitochondria of the resulting progeny were examined under non-selective conditions. These experiments
provide insights into events which are possibly similar to those occurring in nature. The heterokaryons obtained formed both
oligomycin-resistant and -sensitive sectors, most of which were found to be homoplasmons. Progenies harbouring oligomycin-resistant
and -sensitive mtDNAs may originate either from individual recombination events or be due to parental segregation. MtDNA recombination
might take place in the heterokaryons without selection by oligomycin. The most frequent recombinant types of mtDNA RFLP profiles
were indistinguishable from those recombinant mtDNAs which were frequently obtained under selection pressure from directed
transfer experiments between incompatible strains. We present evidence that mixed mitochondrial populations may influence
the compatibility reactions in the presence of an isogenic nuclear background, that recombination may take place without selection
pressure, and that the process does not require specific nuclear sequences of both parental strains.
Received: 20 October 1997 / 13 January 1998 |
| |
Keywords: | Mitochondrial DNA Recombination without selection Aspergillus heterokaryons |
本文献已被 SpringerLink 等数据库收录! |
|