Biomaterial Database

Transmission and recombination of extranuclear genes during sexual crosses in Aspergillus nidulans. 1975

J R Mason, and G Turner

Three extranuclear mitochondrial mutations in Aspergillus nidulans, (oliA1), (camA1) and (cs67), were used as markers in sexual crosses to provide information on the frequencies of transmission and recombination of the mitochondrial genome. Any individual perithecium contained ascospores of only one extranuclear genotype. Using mono-, bi- and trifactorial crosses it was found that all three markers could be recovered from the progeny, although the transmission frequencies were different for each marker. This bias was present irrespective of the nuclear background or the presence of selective agents in the medium on which the cross was established. These findings enable a series of "transmission strength" to be established, as shown below:-- (camA1) greater than (cs67, camA1) greater than (+) = (cs67) greater than (oliA1, cs67) greater than (oliA1) greater than (oliA1, camA1). However, the numbers of recombinants isolated were so variable as to make this form of analysis unsuitable for mapping the mitochondrial genome.

UI	MeSH Term	Description	Entries
D008928	Mitochondria	Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)	Mitochondrial Contraction,Mitochondrion,Contraction, Mitochondrial,Contractions, Mitochondrial,Mitochondrial Contractions
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D009840	Oligomycins	A closely related group of toxic substances elaborated by various strains of Streptomyces. They are 26-membered macrolides with lactone moieties and double bonds and inhibit various ATPases, causing uncoupling of phosphorylation from mitochondrial respiration. Used as tools in cytochemistry. Some specific oligomycins are RUTAMYCIN, peliomycin, and botrycidin (formerly venturicidin X).	Oligomycin
D011995	Recombination, Genetic	Production of new arrangements of DNA by various mechanisms such as assortment and segregation, CROSSING OVER; GENE CONVERSION; GENETIC TRANSFORMATION; GENETIC CONJUGATION; GENETIC TRANSDUCTION; or mixed infection of viruses.	Genetic Recombination,Recombination,Genetic Recombinations,Recombinations,Recombinations, Genetic
D002701	Chloramphenicol	An antibiotic first isolated from cultures of Streptomyces venequelae in 1947 but now produced synthetically. It has a relatively simple structure and was the first broad-spectrum antibiotic to be discovered. It acts by interfering with bacterial protein synthesis and is mainly bacteriostatic. (From Martindale, The Extra Pharmacopoeia, 29th ed, p106)	Cloranfenicol,Kloramfenikol,Levomycetin,Amphenicol,Amphenicols,Chlornitromycin,Chlorocid,Chloromycetin,Detreomycin,Ophthochlor,Syntomycin
D003433	Crosses, Genetic	Deliberate breeding of two different individuals that results in offspring that carry part of the genetic material of each parent. The parent organisms must be genetically compatible and may be from different varieties or closely related species.	Cross, Genetic,Genetic Cross,Genetic Crosses
D004352	Drug Resistance, Microbial	The ability of microorganisms, especially bacteria, to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).	Antibiotic Resistance,Antibiotic Resistance, Microbial,Antimicrobial Resistance, Drug,Antimicrobial Drug Resistance,Antimicrobial Drug Resistances,Antimicrobial Resistances, Drug,Drug Antimicrobial Resistance,Drug Antimicrobial Resistances,Drug Resistances, Microbial,Resistance, Antibiotic,Resistance, Drug Antimicrobial,Resistances, Drug Antimicrobial
D005111	Extrachromosomal Inheritance	Vertical transmission of hereditary characters by DNA from cytoplasmic organelles such as MITOCHONDRIA; CHLOROPLASTS; and PLASTIDS, or from PLASMIDS or viral episomal DNA.	Cytoplasmic Inheritance,Extranuclear Inheritance,Inheritance, Cytoplasmic,Inheritance, Extrachromosomal,Inheritance, Extranuclear
D005796	Genes	A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.	Cistron,Gene,Genetic Materials,Cistrons,Genetic Material,Material, Genetic,Materials, Genetic
D005838	Genotype	The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.	Genogroup,Genogroups,Genotypes