motA1552, a mutation of Dictyostelium discoideum having pleiotropic effects on motility and discoidin I regulation.

Genetics ◽  
1988 ◽  
Vol 118 (3) ◽  
pp. 425-436
Author(s):  
S C Kayman ◽  
R Birchman ◽  
M Clarke
Keyword(s):  
Linkage Group ◽  
Dictyostelium Discoideum ◽  
Growth Temperature ◽  
Segregation Analysis ◽  
Pleiotropic Effects ◽  
Temperature Sensitive ◽  
Temperature Induction ◽  
Group Ii ◽  
Unstable Mutations ◽  
Axenic Growth

Abstract The Dictyostelium discoideum mutant MC2 exhibits temperature-sensitive growth, temperature-sensitive motility, and temperature induction of discoidin I synthesis. These three phenotypes of MC2 were not separated in the genetic experiments reported here. They were therefore assigned to the mutation motA1552, which was mapped to linkage group II by segregation analysis and by analysis of mitotic recombinant diploids. In one motA1552 strain, loss of motility preceded accumulation of discoidin I by 3 hr, indicating that discoidin I is not involved in generation of the motility defect. Expression of motA1552 phenotypes varied both among strains carrying the mutation, and among different clones of a particular strain. MC2 and its derivatives displayed elevated levels of recombination between whiA and acrA on linkage group II, and yielded highly unstable mutations at the acrA locus. Accumulation of large amounts of discoidin I during axenic growth of strain AX3 was found to depend on the presence of a second linkage group II mutation, daxA1551. This mutation was already present in the strain mutagenized to isolate motA1552, complicating explication of motA1552 action.

scholarly journals THE USE OF RESTRICTION FRAGMENT LENGTH POLYMORPHISMS AND DNA DUPLICATIONS TO STUDY THE ORGANIZATION OF THE ACTIN MULTIGENE FAMILY IN DICTYOSTELIUM DISCOIDEUM

Genetics ◽  
1986 ◽  
Vol 112 (1) ◽  
pp. 27-42
Author(s):  
Dennis L Welker ◽  
K Peter Hirth ◽  
Patricia Romans ◽  
Angelika Noegel ◽  
Richard A Firtel ◽  
...  
Keyword(s):  
Linkage Group ◽  
Dictyostelium Discoideum ◽  
Restriction Fragment ◽  
Fragment Length ◽  
Gene Copy ◽  
Actin Genes ◽  
Group I ◽  
Group Ii ◽  
Cloned Gene ◽  
Restriction Fragment Length

ABSTRACT The techniques of restriction fragment length polymorphism analysis and examination of gene copy number in duplication-bearing Dictyostelium discoideum strains have been used to map four actin genes of the wild-type strain NC4 to specific linkage groups. In part, this was accomplished by identification of restriction fragments corresponding to particular cloned actin genes using genespecific probes from unique sequence 5' and 3' untranslated regions. Cloned gene Actin 8 (designation act-8) maps to linkage group I; Actins 12 (act-12) and M6 (actM6) to linkage group II. An uncloned gene (act-100) also maps to linkage group II in the same region as actM6, as defined by a chromosomal duplication. From analysis of other wild isolates of D. discoideum, it was determined that in these isolates at least two actin genes map to linkage group I and at least four map to linkage group II. These results demonstrate the utility of molecular techniques in genetic analysis of Dictyostelium, particularly for developmentally regulated genes that have been cloned but that have no identified mutant phenotypes.

scholarly journals The discoidin I gene family of Dictyostelium discoideum is linked to genes regulating its expression.

Genetics ◽  
1988 ◽  
Vol 119 (3) ◽  
pp. 571-578
Author(s):  
D L Welker
Keyword(s):  
Linkage Group ◽  
Gene Family ◽  
Dictyostelium Discoideum ◽  
Restriction Fragment ◽  
Fragment Length ◽  
Regulatory Element ◽  
Cellular Slime Mold ◽  
Regulatory Loci ◽  
Group Ii ◽  
Restriction Fragment Length

Abstract The discoidin I protein has been studied extensively as a marker of early development in the cellular slime mold Dictyostelium discoideum. However, like most other developmentally regulated proteins in this system, no reliable information was available on the linkage of the discoidin genes to other known genes. Analysis of the linkage of the discoidin I genes by use of restriction fragment length polymorphisms revealed that all three discoidin I genes as well as a pseudogene are located on linkage group II. This evidence is consistent with the discoidin I genes forming a gene cluster that may be under the control of a single regulatory element. The discoidin I genes are linked to three genetic loci (disA, motA, daxA) that affect the expression of the discoidin I protein. Linkage of the gene family members to regulatory loci may be important in the coordinate maintenance of the gene family and regulatory loci. A duplication affecting the entire discoidin gene family is also linked to group II; this appears to be a small tandem duplication. This duplication was mapped using a DNA polymorphism generated by insertion of the Tdd-3 mobile genetic element into a Tdd-2 element flanking the gamma gene. A probe for Tdd-2 identified a restriction fragment length polymorphism in strain AX3K that was consistent with generation by a previously proposed Tdd-3 insertion event. A putative duplication or rearrangement of a second Tdd-2 element on linkage group IV of strain AX3K was also identified. This is the first linkage information available for mobile genetic elements in D. discoideum.

scholarly journals CHROMOSOME FRAGMENTS IN DICTYOSTELIUM DISCOIDEUM OBTAINED FROM PARASEXUAL CROSSES BETWEEN STRAINS OF DIFFERENT GENETIC BACKGROUND

Genetics ◽  
1980 ◽  
Vol 95 (2) ◽  
pp. 289-304
Author(s):  
Keith L Williams ◽  
Gillian E Robson ◽  
Dennis L Welker
Keyword(s):  
Linkage Group ◽  
Genetic Analysis ◽  
Dictyostelium Discoideum ◽  
Genetic Background ◽  
Deleterious Effect ◽  
Fruiting Body Formation ◽  
Body Formation ◽  
Chromosome Fragments ◽  
Group Ii ◽  
Different Genetic Background

ABSTRACT The first aneuploid strains of Dictyostelium discoideum have been unambiguously characterized, using cytological and genetic analysis. Three independently isolated, but genetically similar, fragment chromosomes have been observed in segregants from diploids formed between haploid strains derived from the NC4 and VI2 isolates of D. discoideum. Once generated, the fragment chromosomes, all of which have Vl2-derived centromeres, can be maintained in a NC4 genetic background. Genetic evidence is consistent with the view that all three fragment chromosomes studied encompass the region from the centromere to the whiA locus of linkage group II and terminate in the interval between whiA and acrA. From cytological studies, one of the fragment chromosomes consists of approximately half of linkage group II.——We observed no deleterious effect on viability or asexual fruiting-body formation in either haploid or diploid strains carrying an additional incomplete chromosome and hence are disomic or trisomic, respectively, for part of linkage group II. The incomplete chromosome is lost at a frequency of 2 to 3% from disomic and trisomic strains, but surprisingly this loss is not increased in the presence of the haploidizing agent, benlate. A new locus (clyA), whose phenotype is altered colony morphology, is assigned to the region of linkage group II encompassed by the fragment chromosome.

scholarly journals Motility mutants of Dictyostelium discoideum.

1982 ◽  
Vol 93 (3) ◽  
pp. 705-711 ◽  
Author(s):  
S C Kayman ◽  
M Reichel ◽  
M Clarke
Keyword(s):  
Oxygen Consumption ◽  
Dictyostelium Discoideum ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Track Formation ◽  
Genetic Events ◽  
Axenic Growth

We describe six motility mutants of Dictyostelium discoideum in this report. They were identified among a group of temperature-sensitive growth (Tsg) mutants that had been previously isolated using an enrichment for phagocytosis-defective cells. The Tsg mutants were screened for their ability to produce tracks on gold-coated cover slips, and several strains were found that were temperature-sensitive for migration in this assay. Analysis of spontaneous Tsg+ revertants of 10 migration-defective strains identified six strains that co-reverted the Tsg and track formation phenotypes. Characterization of these six strains indicated that they were defective at restrictive temperature in track formation, phagocytosis of bacteria, and pseudopodial and filopodial activity, while retaining normal rates of oxygen consumption and viability. Because they had lost this group of motile capabilities, these strains were designated motility mutants. The Tsg+ revertants of these mutants, which coordinately recovered all of the motile activities, were found at frequencies consistent with single genetic events. Analysis of the motility mutants and their revertants suggests a relationship between the motility mutations in some of these strains and genes affecting axenic growth.

Linkage group XIX of Chlamydomonas reinhardtii has a linear map.

Genetics ◽  
1993 ◽  
Vol 133 (4) ◽  
pp. 865-874
Author(s):  
J A Holmes ◽  
D E Johnson ◽  
S K Dutcher
Keyword(s):  
Linkage Group ◽  
Chlamydomonas Reinhardtii ◽  
Mutant Strain ◽  
Meiotic Recombination ◽  
Temperature Sensitive ◽  
Unusual Property ◽  
Linkage Groups ◽  
Excess Number ◽  
Chiasma Interference ◽  
Double Crossovers

Abstract Linkage group XIX (or the UNI linkage group) of Chlamydomonas reinhardtii has been reported to show a circular meiotic recombination map. A circular map predicts the existence of strong chiasma and chromatid interference, which would lead to an excess number of two-strand double crossovers during meiosis. We have tested this prediction in multipoint crosses. Our results are consistent with a linear linkage group that shows positive chiasma interference and no chromatid interference. Chiasma interference occurs both within arms and across the centromere. Of the original loci that contributed to the circular map, we find that two map to other linkage groups and a third cannot be retested because the mutant strain that defined it has been lost. A second reported unusual property for linkage group XIX was the increase in meiotic recombination with increases in temperature during a period that precedes the onset of meiosis. Although we observed changes in recombination frequencies in some intervals on linkage group XIX in crosses to CC-1952, and in strains heterozygous for the mutation ger1 at 16 degrees, we also show that our strains do not exhibit the previously observed patterns of temperature-sensitive recombination for two different pairs of loci on linkage group XIX. We conclude that linkage group XIX has a linear genetic map that is not significantly different from other Chlamydomonas linkage groups.

scholarly journals A gene triplet in the mouse

1970 ◽  
Vol 15 (2) ◽  
pp. 227-235 ◽  
Author(s):  
A. G. Searle ◽  
Gillian M. Truslove
Keyword(s):  
Linkage Group ◽  
In Utero ◽  
White Hair ◽  
Close Linkage ◽  
Group Ii ◽  
Tail Tip ◽  
Dominant Spotting

SUMMARYMice heterozygous for rump-white (Rw) have white hair in lumbo-sacral and caudal regions, although the tail-tip is sometimes pigmented. The homozygote is lethal in utero. No recombination has been found between Rw and the very closely linked spotting genes patch (Ph) and the viable allele of W (Wv). The compounds between these genes are all viable and fertile, although individual homozygotes are either lethal (Ph, Rw) or sterile and anaemic (Wv). It is concluded that they are non-allelic, but form a gene triplet. Close linkage between a cluster of dominant spotting genes and an angora gene in mouse and rabbit provide evidence for homology of part of linkage group II in the rabbit and part of linkage group XVII in the mouse.

scholarly journals Curly-whiskers and its linkage with tail-kinks in linkage group II of the mouse

1966 ◽  
Vol 8 (1) ◽  
pp. 111-113 ◽  
Author(s):  
D. S. Falconer ◽  
J. H. Isaacson
Keyword(s):  
Linkage Group ◽  
Inbred Strain ◽  
Recessive Gene ◽  
Coat Colour ◽  
Group Ii ◽  
Research Institute

Curly-whiskers (cw) is a recessive gene which was found in 1958 by Mr C. J. W. Smith of the Chester Beatty Research Institute, London. It arose in a subline of the CBA/Cbi inbred strain. The first mutant animals were one male and one female in a litter of five. The two mutants were mated together and a sib-mated subline was continued from them in which 500 mice were bred, all of which were curly-whiskered. This established the mutant to be fully penetrant. Curly-whiskers resembles the hair-waving genes in causing waving of the vibrissae, but it has no obvious waving effect on the hairs of the coat. The coat texture is, however, slightly abnormal and Mr Smith noted also that on the CBA background there was an appreciable darkening of the coat colour. Homozygotes (cw/cw) are easily classifiable soon after birth by the curled vibrissae. Heterozygotes (+/cw) often have slightly curled vibrissae, and the gene is therefore not fully recessive; but the distinction between +/cw and +/+ could not be relied on, and in the linkage tests cw was treated as a recessive gene.

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