cis-trans test


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cis-trans test

 [sis trans]
a test in microbial genetics to determine whether two mutations that have the phenotypic effects, in a haploid cell or a cell with single phage infection, are located in the same gene or different genes; the test depends on the independent behavior of two alleles of a gene in a diploid cell or in a cell infected with two phages carrying different alleles.
Cis-trans click for a larger image
Fig. 104 Cis-trans test . The cis-trans test configurations. m1 and m2 are mutations. The two lines represent two homologous chromosomes.

cis-trans test

a genetic COMPLEMENTATION TEST to determine if two mutations have occurred within the same CISTRON or in adjacent cistrons. The test depends upon the two mutations being introduced into a cell at the same time. If they ‘complement’ each other by producing a WILD TYPE phenotype the mutations are in different cistrons (i.e. nonallelic). If a mutant phenotype is produced this shows the two mutations to be noncomplementary and therefore to be located in the same cistron (i.e. allelic). Two arrangements are possible in the cis-trans test (see Fig. 104 which can be carried out in a double HETEROZYGOTE individual (a HETEROKARYON in a haploid type). The more important is the transconfiguration, which is diagnostic, since two normal cistrons are present if the mutations are nonallelic (giving wild type) whereas the same cistron is mutant on both chromosomes if the mutations are allelic (giving a mutant phenotype).

test

1. an examination or trial.
2. a significant chemical reaction.
3. a reagent. See also under specific names of tests.

cis-trans test
used in microbial genetics to determine whether two mutations that have the phenotypic effect, in a haploid cell or a cell with single phage infection, are located in the same gene or in different genes; the test depends on the independent behavior of two alleles of a gene in a diploid cell or in a cell infected with two phages carrying different alleles.
critical titer test
the titer of a test at which the patient is judged to have reacted positively to the test.
diazo test
a group of tests for bilirubin conjugates in urine and therefore suitable for the detection of biliary and hepatic disease. Based on the combination of bilirubin with a stable diazonium compound.
exact test
a statistical test based on the exact distribution of the data under the null hypothesis, rather than on a normal approximation.
hypothesis test
the method by which a hypothesis is judged.
sodium sulfanilate clearance test
test station
set up by the government or a cooperative organization for the purpose of testing individual livestock provided by farmers for productivity in terms of egg production, milk yield, weight gain. The feeding and measurement are under the control of the station.
statistical test
used to decide between two hypotheses.
surrogate test
an indirect test, e.g. milk cell count.
tolerance test
1. an exercise test to determine the efficiency of the circulation.
2. determines the body's ability to metabolize a substance or to endure administration of a drug, e.g. insulin tolerance test.
triglyceride absorption test
see fat absorption test.
urine concentration test
see water deprivation test.
V-test
a dexamethasone suppression test followed by an ACTH response test; the name refers to the change in plasma cortisone levels, first depressed then elevated, which if plotted on a graph would form a V.