Estimating the frequencies of MI bivalent types formed by a heterozygous translocation duplication in rye

Genetica ◽  
1980 ◽  
Vol 51 (3) ◽  
pp. 215-219 ◽  
Author(s):  
J. Sybenga ◽  
P. Stam ◽  
H. M. Verhaar
Keyword(s):  
Heterozygous Translocation

RADIATION INDUCED RECIPROCAL TRANSLOCATIONS AND INVERSIONS IN ANOPHELES ALBIMANUS

1982 ◽  
Vol 24 (2) ◽  
pp. 177-188 ◽  
Author(s):  
P. E. Kaiser ◽  
J. A. Seawright ◽  
M. Q. Benedict ◽  
S. Narang ◽  
S. G. Suguna
Keyword(s):  
X Rays ◽  
Anopheles Albimanus ◽  
Reciprocal Translocations ◽  
Pericentric Inversions ◽  
Radiation Induced ◽  
Homozygous Translocation ◽  
Paracentric Inversions ◽  
Heterozygous Translocation

Reciprocal translocations and inversions were induced in Anopheles albimanus Wiedemann by irradiation of males with X rays. A total of 1669 sperm were assayed, and 175 new aberrations were identified as follows: 102 reciprocal translocations (67 autosomal and 35 sex-linked), 45 pericentric inversions, and 28 paracentric inversions. Eleven of the translocations were nearly whole-arm interchanges, and these were selected for the construction of "capture systems" for compound chromosomes. Two double-heterozygous translocation strains and four homozygous translocation strains were established. Anopheles albimanus females were irradiated, and a pseudolinkage scheme involving mutant markers was employed to identify reciprocal translocations. The irradiation of females was very inefficient: only one translocation was recovered from 1080 ova tested.

Incorporation of restoring gene of Aegilops umbellulata into wheat

Genome ◽  
1991 ◽  
Vol 34 (5) ◽  
pp. 727-732 ◽  
Author(s):  
Zheng-Qiang Ma ◽  
Yin-Hai Zhao ◽  
Da-Jun Liu
Keyword(s):  
Chinese Spring ◽  
Fertility Restoration ◽  
Triticum Aestivum L ◽  
Addition Line ◽  
Male Sterile ◽  
Aegilops Umbellulata ◽  
Alien Gene ◽  
Mother Cells ◽  
Type Chromosome ◽  
Heterozygous Translocation

Six 'Chinese Spring' – Aegilops umbellulata Zhuk. addition lines (UAD, UBD, UCD, UDD, UED, and UFM) were assayed for their effects on the fertility of timopheevi cytoplasm male sterile lines (T-type). Chromosome 6U of disomic addition line UAD was found to be able to restore the fertility of T-type male sterility and 'Chinese Spring' was verified to lack restoring genes, indicating that 6U carries at least one fertility restoration gene. From about 200 plants with 42 somatic chromosomes derived from the progeny of crosses Qu Xian Early A × UAD and Sumai No. 3 A × UAD, eight self-fertile plants were selected. Their self-fertility in timopheevi cytoplasm implies that they carry the restoring gene(s) from 6U. Cytological analysis was conducted on the hybrid F1 of the selected fertile plants (040-5, 060-1, and 061-4) as female parents crossed with 'Chinese Spring'. The self-fertility segregation and the chromosome pairing of pollen mother cells of F1 fertile plants from 040-5, 060-1, and 061-4 × 'Chinese Spring' during meiosis suggested that they were heterozygous translocation lines with restoring gene(s) from 6U.Key words: Aegilops umbellulata Zhuk., restoring genes, alien gene transfer, timopheevi cytoplasmic male sterile fertility, Triticum aestivum L.

RECIPROCAL TRANSLOCATIONS AND TRANSLOCATION DISOMICS OF ASPERGILLUS AND THEIR USE FOR GENETIC MAPPING

Genetics ◽  
1975 ◽  
Vol 79 (1) ◽  
pp. 7-30
Author(s):  
Etta Käfer
Keyword(s):  
Genetic Mapping ◽  
Relative Position ◽  
Normal Chromosome ◽  
Large Chromosome ◽  
Reciprocal Translocations ◽  
New Techniques ◽  
Chromosome Arm ◽  
Chromosome Segments ◽  
Heterozygous Translocation

ABSTRACT Two new techniques are described for genetic mapping of reciprocal translocations in A. nidulans, which can be used to locate centromeres and meiotically unlinked markers. They both make use of unbalanced disomics from heterozygous translocation crosses. These are mainly hyperhaploids of two classes: either typical-looking n + 1 with a normal chromosome in addition to a haploid set containing the translocation, or translocation disomics. When large chromosome segments are involved, such disomics, as well as stable aneuploids and duplication types, show characteristic phenotypes and can be classified visually. The first method maps translocation breaks qualitatively, since translocated markers can be identified when translocation disomics are analyzed for heterozygous markers. The second method measures meiotic linkage of any marker to the translocation breaks when allele ratios in the balanced haploid sectors of either or both classes of disomics are determined: linked markers show reciprocal deviations from 1:1—In addition, it can be shown that frequencies of nondisjunction and recovery of specific translocation disomics both depend on the relative position of the break within a chromosome arm. Such information can provide a rough estimate of the positions of breaks for a new translocation.—Using these techniques, as well as mitotic mapping in homo- and heterozygous translocation diploids, four reciprocal translocations were mapped. From these results, information on the sequence and orientation of most of the "meiotic fragments" of the current maps (groups III, VI, VII and VIII) was obtained, and the position of the centromeres of groups VI and VII were identified. Translocation disomics are also used to map meiotically unlinked single genes, e.g. oliA of group VII, to specify chromosome segments.

THE EFFECT OF MITOMYCIN ON THE FERTILITY AND THE INDUCTION OF MEIOTIC CHROMOSOME REARRANGEMENTS IN MICE AND THEIR FIRST GENERATION PROGENY

1977 ◽  
Vol 19 (3) ◽  
pp. 387-393 ◽  
Author(s):  
N. Savković ◽  
S. Green ◽  
J. Pečevski ◽  
N. Marić
Keyword(s):  
Reproductive Performance ◽  
First Generation ◽  
Chronic Treatment ◽  
Meiotic Chromosome ◽  
Chromosomal Translocations ◽  
Cytological Analysis ◽  
Pregnant Females ◽  
Generation Progeny ◽  
Dose Dependent ◽  
Heterozygous Translocation

The dose dependent effects of chronic application of Mitomycin C(MC) on the induction of chromosomal translocations in treated animals and F1 males and on their fertility have been examined. The C3H strain mice used in the present experiments were treated with MC during eight successive weeks in doses of 0.05 mg/kg and 0.1 mg/kg of body weight. 75 males were treated (25 males per dose and 25 males as controls). Immediately after the chronic treatment they were mated with normal females and were tested for their reproductive performance. The fertility of males was estimated from the number of pregnant females after one week of being together. After that all males were sacrificed and prepared for cytological analysis. No chromosomal translocations were found in diakinesis-metaphase I of meiosis. Data from the study of fertility showed that all treated males were fertile, but all females were not pregnant. The testes of all sterile, semisterile and fertile F1 males showed that F1 males could not be identified as heterozygous translocation carriers.

scholarly journals DETECTION AND IDENTIFICATION OF TRANSLOCATIONS BY INCREASED SPECIFIC NONDISJUNCTION IN ASPERGILLUS NIDULANS

Genetics ◽  
1974 ◽  
Vol 76 (1) ◽  
pp. 19-31
Author(s):  
Alan Upshall ◽  
Etta Käfer
Keyword(s):  
Aspergillus Nidulans ◽  
Genetic Factors ◽  
Visual Detection ◽  
Control Level ◽  
Linkage Groups ◽  
Detection And Identification ◽  
Induced Mutants ◽  
Morphological Mutants ◽  
Average Control ◽  
Heterozygous Translocation

ABSTRACT A meiotic technique for visual detection of translocations has been applied to ten mitotically identified interchanges, and three new translocations were discovered using this method. Testcrosses between "standard" strains and potential translocation strains—e.g. strains with newly induced mutants or descendants from translocation crosses—are inspected for the frequency of abnormal-looking colonies. In all heterozygous translocation crosses "abnormals" are increased at least tenfold compared to the average control level of 0.15%. Most of these are disomics, and can be recognized by their characteristic phenotypes. Each translocation produces a few specific types, since nondisjunction is increased mainly in the linkage groups involved in the translocation (50–100-fold over control values). Therefore, translocations were not only detected but often tentatively assigned to linkage groups from the analysis of the disomic progeny in crosses. In addition, this technique allows reciprocal and nonreciprocal translocations to be distinguished, since only the latter produce one-third phenotypically abnormal duplication progeny. While results are clearcut in most cases, occasionally problems are encountered, e.g. when morphological mutants segregate in crosses, or when other genetic factors which increase or reduce the frequency of nondisjunction are present in certain strains.

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