DETERMINATION OF BREAKPOINT POSITIONS IN BARLEY TRANSLOCATIONS BY KARYOTYPE ANALYSIS OF PERMANENT RINGS OF SIX CHROMOSOMES

1974 ◽  
Vol 16 (3) ◽  
pp. 539-548 ◽  
Author(s):  
N. A. Tuleen ◽  
J. H. Gardenhire
Keyword(s):  
Karyotype Analysis ◽  
Chromosome 1 ◽  
Crossing Over ◽  
Differential Segment

Five T1-5 and 10 T1-6 barley translocations were crossed with the translocation T1-7f. Plants in which the T1-5 and T1-6 translocations had been combined with T1-7f due to crossing over in the differential segment were selected in the F2 generation. One of the chromosomes present in plants carrying the translocations in the combined form is made up of parts of the three chromosomes involved in the two translocations, and the segmental arrangement of this tripartite chromosome is determined by the position of the breakpoints in chromosome 1. The karyotypes of these stocks were analyzed and the breakpoints in seven of the translocations were assigned to the same arm and eight to the opposite arm of chromosome 1 relative to the position of the breakpoint in T1-7f.

CROSSING OVER IN A DOUBLE TRANSLOCATION IN DROSOPHILA

1972 ◽  
Vol 14 (1) ◽  
pp. 129-137 ◽  
Author(s):  
A. S. Robinson ◽  
C. F. Curtis
Keyword(s):  
Drosophila Melanogaster ◽  
Pest Control ◽  
The Other ◽  
Crossing Over ◽  
Male And Female ◽  
Differential Segment ◽  
Translocation Heterozygote

The production and fertility of a double translocation heterozygote in Drosophila melanogaster are reported. A difference in the fertility of male and female double heterozygotes was recorded and explained on the basis of crossing over, occurring in the differential segments of female double heterozygotes, producing extra unbalanced gametes. It was shown that crossing over was absent from one differential segment but the amount of crossing over occurring in the other differential segment was measured. The possible use of multiple translocation systems for pest control is discussed with particular reference to the use of double translocation heterozygotes.

scholarly journals Molecular characterization of chemical mutagenesis induced diversity in elite maize germplasm

Genetika ◽  
2004 ◽  
Vol 36 (1) ◽  
pp. 47-60 ◽  
Author(s):  
Nikolai Christov ◽  
Elena Todorovska ◽  
Dionysia Fasoula ◽  
Ioannis Ioannides ◽  
Atanas Atanassov ◽  
...  
Keyword(s):  
Flowering Time ◽  
Molecular Characterization ◽  
Pcr Amplification ◽  
Inbred Lines ◽  
Chromosome 1 ◽  
Chemical Mutagenesis ◽  
Maize Germplasm ◽  
Mutant Lines

Three classical breeding Iowa Super Stiff Stalk (SSS) inbred lines B37, B73 and B84, one Lancaster inbred Oh43 and mutant lines obtained by chemical mutagenesis followed by mutation breeding as follows: two of B37 and four of Oh43 were selected for molecular characterization. The mutant inbred lines were chosen because in addition to the improved GCA and SCA for grain yield, proven by their predominance in the Bulgarian breeding programs, they showed shifts in the flowering time as compared to the initial inbreds. Molecular markers (micro satellites and other PCR-based DNA markers) were used for characterization of maize genotypes and determination of the induced by chemical mutagenesis genetic variability in maize germplasm. The tested nine SSR markers (umc 1001, umclO14, umcl057, umcll81, umcl0lS, umc 1029. umcl003, umc 1033 and umcl035) can discriminate between the initial classical breeding inbred lines and the originating mutant inbreds. Allelic diversity was also studied by PCR amplification with specifically de-signed primers in the coding regions and flanking sequence of two genes: dwarf8 (d&: chromosome 1, 198.5 cM), and indeterminate l (id1; chromosome 1. 175.0 cM). These are considered candidate genes for variation in plant height and/or flowering time, based on mutant phenotypes and chromosomal locations near major QTLs. Single nucleotide polymorphisms and indels were detected in the region flanking the SH2 domain of dwarf8 gene in some of the mutant inbreds as a result of SSCP and sequencing analyses. However, these polymorphisms could not be associated with the observed variations in flowering time. PCR analysis of the promoter region dwarf8 showed a variant fragment of about 1 kb in the inbred line Oh43 that was not present in any other initial and mutant in-bred lines included in the study. PCR amplification of the 5' end of the Id1 coding sequence revealed polymorphic bands in the mutant lines XM535, XM521, XM250-l, XM98-8 and XM85-105, as well as in the classical breeding line B73. The data, presented here demonstrate the usefulness of chemical mutagenesis for generation of genetic diversity within the elite maize germplasm. Some of this variation may affect the major genes in the QTLs. Our initial data revealed mutagenesis induced polymorphisms in the coding sequences of two important for the determination of flowering time transcription factors. Further molecular analyses of the proposed model systems may complement the trait association efforts and will help to directly identify the major genes in the QTLs.

THE RELATIONSHIP BETWEEN CHIASMATA AND CROSSING OVER IN TRITICUM AESTIVUM

Genetics ◽  
1973 ◽  
Vol 75 (2) ◽  
pp. 231-246
Author(s):  
T K Fu ◽  
E R Sears
Keyword(s):  
Chiasma Frequency ◽  
Rust Resistance ◽  
Genetic Recombination ◽  
Substantial Reduction ◽  
Leaf Rust Resistance ◽  
Crossing Over ◽  
Two Temperatures ◽  
Independent Behavior ◽  
The Relationship

ABSTRACT Telocentrics for the β arm of chromosome 4A and the long arm of 6B were used as cytological markers for the determination of chiasma frequency. In concomitant studies of recombination, terminal segments of rye and T. umbellulatum chromatin carrying Hp (Hairy peduncle) and Lr9 (Leaf-rust resistance), respectively, marked 4A and 6B. Two temperatures, 21° and 32°, were used for both the 4A and 6B experiments.—Only one chiasma was observed in each heteromorphic bivalent. Because there was a substantial reduction in pairing between diakinesis and metaphase I, all determinations of chiasma frequency were made at diakinesis. In the 21° experiments, agreement was good between genetic recombination and cytological prediction on the basis of the partial chiasmatypy hypothesis that each chiasma represents a crossover. At 32° both chiasma frequency and crossing over, but particularly the latter, were strongly reduced. The fewer crossovers than expected are explained in part by stickiness of chromosomes at the high temperature, sometimes resulting in adjacent chromosomes being wrongly scored as having a chiasma, and in part by premetaphase disjunction of some recombined bivalents and subsequent independent behavior of the two resulting univalents.—Male transmission of the 4A telocentric from the heteromorphic bivalent was unusually high: 51% at 21° and 31% at 32°.

Prospects for introgressing tomato chromosomes into the potato genome: An assessment through GISH analysis

Genome ◽  
1999 ◽  
Vol 42 (2) ◽  
pp. 282-288 ◽  
Author(s):  
F Garriga-Calderé ◽  
D J Huigen ◽  
E Jacobsen ◽  
M S Ramanna
Keyword(s):  
Low Frequency ◽  
Chromosome 8 ◽  
Chromosome 1 ◽  
Crossing Over ◽  
Homoeologous Pairing ◽  
Potato Genome ◽  
Somatic Fusion ◽  
Tomato Chromosome ◽  
Genomic In Situ Hybridisation ◽  
Monosomic Addition

With a view to assess the possibility of homoeologous pairing and crossing-over between the chromosomes of potato (Solanum tuberosum) and tomato (Lycopersicon esculentum), a somatic fusion hybrid and two monosomic alien tomato addition genotypes were investigated through genomic in situ hybridisation (GISH). The somatic fusion hybrid, C31-17-51, was near hexaploid (2n = 6x - 4 = 68) possessing 46 potato chromosomes + 20 tomato chromosomes + 2 translocated chromosomes. The two alien addition genotypes were near tetraploids (2n = 4x + 1 = 49) and consisted of monosomic alien additions for tomato chromosome 1 in genotype 2103-1, and tomato chromosome 8 in genotype 2301-2. In the fusion hybrid the tomato pachytene chromosome identification revealed that the chromosomes 1, 2, 5, 6, 7, 10, and 12 were in diploid condition whereas among those that were in haploid condition, three could be identified viz., 4, 9, and 11. The remaining three chromosomes could not be cytologically identified. Although the chromosomes with translocated segments could not be identified at the pachytene stage due to technical difficulties, there was clear evidence for the presence of a reciprocal translocation observed at diakinesis and metaphase I stages. Because of autosyndetic pairing of the translocated segments, it gave a false impression as if there was a high frequency (86.0%) of allosyndetic pairing. In contrast to the fusion hybrid, the two alien monosomic addition genotypes showed a very low frequency of allosyndetic pairing, namely 1.1 and 1.3% respectively for the monosomic additions 1 and 8. In the genotype 2301-2, monosomic addition for tomato chromosome 8, crossing-over between the homoeologous chromosomes was estimated to occur in 0.8% of the meiotic cells investigated. Despite this low frequency of homoeologous pairing and crossing-over, there is a possibility for introgressing tomato chromosomal DNA into the potato genome through intergenomic recombination.Key words: Solanum, Lycopersicon, chromosome additions, GISH, introgression.

Karyotype analysis of teratocarcinomas and embryoid bodies of C3H mice

Development ◽  
1977 ◽  
Vol 38 (1) ◽  
pp. 77-92
Author(s):  
S. A. Iles ◽  
E. P. Evans
Keyword(s):  
Karyotype Analysis ◽  
Normal Karyotype ◽  
Embryoid Bodies ◽  
Mouse Embryos ◽  
Chromosome 1 ◽  
Chromosome 11 ◽  
The Third ◽  
Wide Range ◽  
C3h Mice ◽  
Length Changes

Karyotype and capacity for differentiation were determined in four transplantable teratomas, and their embryoid bodies, derived from C3H mouse embryos. An apparently normal karyotype was retained by one tumour and one subline that were able to differentiate into a wide range of tissues, but some chromosomal alterations were found in the two tumours and one subline that showed almost identical restrictions in their capacity for differentiation. Trisomy for chromosome 11 was shared by all three restricted tumours; two of the tumours had similar length changes in the same two chromosome (1 and 14) while the third was generally trisomic for four other chromosomes.

A CROSSOVER SUPPRESSOR-ENHANCER SYSTEM IN THE MOSQUITO AEDES AEGYPTI

1971 ◽  
Vol 13 (3) ◽  
pp. 561-577 ◽  
Author(s):  
Satish C. Bhalla
Keyword(s):  
Linkage Group ◽  
Reciprocal Translocation ◽  
Paracentric Inversion ◽  
Chromosome 1 ◽  
Crossing Over ◽  
Linkage Groups ◽  
Group Iii ◽  
Partial Sterility ◽  
The Right ◽  
And Inversion

A small reciprocal translocation T(1;2)1 involving chromosomes 1 and 2 and a paracentric inversion In(1)3 on m chromosome (1) of A. aegypti interact to give peculiar but consistent crossover values. The system is termed COSES and is associated with partial sterility. In females it suppresses crossing over tremendously to the right of bz and enhances crossing over to its left. In the males it enhances crossing over to the right of m (only 3 crossover units away from bz) hut the region to its left remains unaffected. COSES also displays interchromosomal effects by enhancing crossing over in linkage group III. Cytological and genetic evidence for the presence of translocation and inversion are presented. All three pairs of chromosomes are correlated to the three linkage groups.

The determination of position in crossing-over

1936 ◽  
Vol 33 (2) ◽  
pp. 207-235 ◽  
Author(s):  
K. Mather
Keyword(s):  
Crossing Over

Direct and Indirect Assessment of the Aneuploidy-inducing Potency of Organotin Compounds

1991 ◽  
Vol 19 (2) ◽  
pp. 214-218
Author(s):  
Klaus Gjervig Jensen ◽  
Ole Andersen ◽  
Mogens Rønne
Keyword(s):  
Average Length ◽  
Human Lymphocytes ◽  
Organotin Compounds ◽  
Chromosome 1 ◽  
Tributyltin Chloride ◽  
Human Peripheral Lymphocytes ◽  
Triphenyltin Chloride ◽  
Spindle Function

The spindle-inhibiting and aneuploidy-inducing potency of in vitro exposure of PHA-stimulated human lymphocytes to organotin compounds has been studied indirectly by quantitation of chromosomal contraction and directly by determination of the frequency of aneuploidy by chromosome counting. The effects of trimethyltin chloride (TMT), dimethyltin chloride (DMT), tributyltin chloride (TBT), dibutyltin chloride (DBT), triphenyltin chloride (TPhT), and diphenyltin chloride (DPhT) on chromosal contraction were studied at concentrations of 10-3-10 9M, by measurement of the average length of chromosome 1 from asynchronous cultures of human peripheral lymphocytes. TMT, TBT, TPhT and DPhT appear to be very strong inducers of chromosomal supercontraction, indicating that these compounds are possible spindle inhibitors, while DMT and DBT seem to be ineffective. TMT, TBT, TPhT and DPhT gave rise to a little more than 100% increase in the number of hyperdiploid cells, all the increases being statistically significant except for that induced by TBT, indicating that organotin compounds are capable of inducing aneuploidy, probably by affecting spindle function.

scholarly journals Dimorphic Mating-Type Chromosomes in the Fungus Microbotryum violaceum

Genetics ◽  
2002 ◽  
Vol 160 (2) ◽  
pp. 457-461 ◽  
Author(s):  
Michael E Hood
Keyword(s):  
Mating Type ◽  
Sex Chromosomes ◽  
Dna Sequences ◽  
Karyotype Analysis ◽  
Sequence Similarity ◽  
Large Degree ◽  
Microbotryum Violaceum ◽  
Mating Compatibility ◽  
Electrophoretic Techniques

Abstract Fungi often mate as haploids, and sex chromosomes (i.e., mating-type chromosomes) that are dimorphic for their size or overall DNA content have never been reported in this kingdom. Using electrophoretic techniques for karyotype analysis, a highly dimorphic chromosome pair that determines mating compatibility is shown to occur in populations of the fungus Microbotryum violaceum. This substantiates the evolution of such dimorphism as a general feature associated with haploid determination of mating compatibility, which previously had been known only in haplodioecious plants (mosses and liverworts). Size-dimorphic sex chromosomes are present in a lineage of M. violaceum native to Europe, as well as a lineage native to North America. However, they are very different in size between these lineages, indicating either independent evolution of the dimorphism or a large degree of divergence since their isolation. Several DNA sequences that show sequence similarity to transposons were isolated from these sex chromosomes.

Gene transfer by means of cell fusion. II. The mapping of 8 loci on human chromosome 1 by statistical analysis of gene assortment in somatic cell hybrids

1977 ◽  
Vol 25 (1) ◽  
pp. 39-57 ◽  
Author(s):  
S.J. Goss ◽  
H. Harris
Keyword(s):  
Statistical Analysis ◽  
Human Chromosome ◽  
Chromosome 1 ◽  
Human Chromosomes ◽  
Hybrid Cells ◽  
Somatic Cell Hybrids ◽  
Human Chromosome 1 ◽  
Chromosome I ◽  
Band Material

A method is described which should permit determination of the order and spacing of genes on all human chromosomes by the analysis of just one set of man-mouse hybrid cells. This method is used to determine the map of 8 loci on human chromosome I. A comparison of the statistical maps of chromosome I and of the X-chromosome with the cytogenetic maps of these chromosomes at metaphase indicates that the statistically derived distances between genes are related to the amount of Giemsa light-band material between the genes.

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