Abstract
The streptomycin sensitive (ss-) revertants of the streptomycin dependent mutant sd3 segregate on streptomycin medium again sd-cells. This sd-segregation decreases continuously with increasing time of cultivation until zero-level is reached.
The revertant R 20 differ from the other revertants mainly that the rate of segregation remaining almost at the same high level a long time. But the results of clonings showed that also in R 20 the number of cells able to segregate sd-cells decreases. After 6 months, only 20% of the cells still possessed this ability.
Former investigations showed that the ss-revertants still had sd-informations. These informations segregate in the following cell-divisions and produce again sd-colonies on the streptomycin medium. The rate of segregation was changing with the different clones. This proves the non-oriented distribution of the sd- and ss-gene copies at the mitotic division. The clonings demonstrate also the existence of much more than 2 copies.
According to Sager and Ramanis the genes of the chloroplast exist at the most in 2 copies. If the statement should be true in principle for all vegetative cells, then the sd-information cannot be in the chloroplast. It must be located in the mitochondria.
Similar content being viewed by others
Literatur
Gillham, N. W.: The nature of exceptions to the pattern of uniparental inheritance for high level streptomycin resistance in Chlamydomonas reinhardi. Genetics 48, 431–439 (1963).
—: Induction of chromosomal and nonchromosomal mutations in Chlamydomonas reinhardi with N-methyl-N'-nitro-N-nitrosoguanidine. Genetics 52, 529–537 (1965).
Sager, R., Ramanis, Z.: The particulate nature of nonchromosomal genes in Chlamydomonas. Proc nat. Acad. Sci. (Wash.) 50, 260–268 (1963).
——: Biparental inheritance of nonchromosomal genes induced by ultraviolet irradiation. Proc. nat. Acad. Sci. (Wash.) 58, 931–937 (1967).
——: The pattern of segregation of cytoplasmic genes in Chlamydomonas. Proc. nat. Acad. Sci. (Wash.) 61, 324–331 (1968).
——: A genetic map of non-mendelian genes in Chlamydomonas. Proc. nat. Acad. Sci. (Wash.) 65, 593–600 (1970).
Schimmer, O., Arnold, C. G.: Untersuchungen zur Lokalisation eines außerkaryotischen Gens bei Chlamydomonas reinhardi. Arch. Mikrobiol. 66, 199–202 (1969).
——: Untersuchungen über Reversions- und Segregationsverhalten eines außerkaryotischen Gens bei Chlamydomonas reinhardii zur Bestimmung des Erbträgers. Molec. Gen. Genetics 107, 281–290 (1970)
Author information
Authors and Affiliations
Additional information
Vorgelegt von G. Melchers
Rights and permissions
About this article
Cite this article
Schimmer, O., Arnold, C.G. Über die Zahl der Kopien eines außerkaryotischen Gens bei Chlamydomonas reinhardii . Molec. Gen. Genet. 107, 366–371 (1970). https://doi.org/10.1007/BF00441198
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00441198