Spindle disappearance and chromosome behavior after partial-embryo irradiation in Cecidomyiidae (Diptera)

Chromosoma ◽  
1961 ◽  
Vol 12 (1) ◽  
pp. 233-247 ◽  
Author(s):  
Irene Geyer-Duszyńska
Keyword(s):  
Chromosome Behavior ◽  
Partial Embryo

Meiotic chromosome behavior of Haworthia limifolia

2016 ◽  
Vol 5 (03) ◽  
pp. 4902
Author(s):  
Afrin Nazli ◽  
Kamini Kumar*
Keyword(s):  
Genetic Recombination ◽  
Meiotic Chromosome ◽  
Pollen Sterility ◽  
Meiotic Abnormalities ◽  
Chromosome Behavior ◽  
The Family ◽  
Medicinal Properties ◽  
Fruit Formation ◽  
Meiosis I ◽  
Chromosomal Behaviour

Haworthia limifolia is a xerophytic plant belonging to the family Liliaceae and is indigenous to Africa. It is use extensively for its medicinal properties like antibacterial, antifungal properties and used for the treatment of sores, superficial burns, as a blood purifier and to promote pregnancy in women and cattles. In present investigation chromosomal behaviour of H. limifolia in meiosis was studied. In diplotene stage chiasmata was observed showing the possibilities of genetic recombination. Chromosome clumps were observed in diakinesis indicating sticky nature of chromosomes. Meiotic abnormalities like stickiness, precocious movement, formation of bridges and laggards were also reported in both meiosis I and II. A fairly high percentage of pollen sterility that is 73.41% was recorded resulting in failure of fruit formation. This plant could be designated as facultative apomict (Swanson, 1957) as the only means of reproduction found was asexual or vegetative.

scholarly journals Do s genes or deleterious recessives control late-acting self-incompatibility in Handroanthus heptaphyllus (Bignoniaceae)? A diallel study with four full sib progeny arrays

2021 ◽  
Author(s):  
Marta B Bianchi ◽  
Thomas R Meagher ◽  
Peter E Gibbs
Keyword(s):  
Genetic Control ◽  
Inbreeding Depression ◽  
Fruit Set ◽  
Genetic Model ◽  
Pollen Tubes ◽  
Self Incompatibility ◽  
Significant Difference ◽  
Partial Embryo ◽  
Ovule Penetration ◽  
S Genes

Abstract Background and Aims Genetically controlled self-incompatibility (SI) mechanisms constrain selfing and thus have contributed to the evolutionary diversity of flowering plants. In homomorphic gametophytic SI (GSI) and homomorphic sporophytic SI (SSI), genetic control is usually by a single multi-allelic locus S. Both GSI and SSI prevent self pollen tubes reaching the ovary and so are pre-zygotic in action. In contrast, in taxa with late-acting self-incompatibility (LSI), rejection is often post-zygotic, since self-pollen tubes grow to the ovary where fertilization may occur prior to floral abscission. Alternatively, lack of self fruit set could be due to early-acting inbreeding depression (EID). The aim of our study was to investigate mechanisms underlying lack of selfed fruit set in Handroanthus heptaphyllus in order to assess the likelihood of LSI versus EID. Methods We employed four full sib diallels to study the genetic control of LSI in Handroanthus heptaphyllus using a precociously flowering variant. We also used fluorescence microscopy to study the incidence of ovule penetration by pollen tubes in pistils that abscised following pollination or initiated fruits. Key Results All diallels showed reciprocally cross-incompatible full-sibs (RCI), reciprocally cross compatible full-sibs (RCC), and non-reciprocally compatible full-sibs (NRC) in almost equal proportions. There was no significant difference between the incidence of ovule penetrations in abscised pistils following self- and cross-incompatible pollinations, but those in successful cross pollinations were around twofold greater. Conclusions A genetic model postulating a single S locus with four s alleles, one of which, in the maternal parent, is dominant to the other three, will produce RCI, RCC and NRC situations each at 33 %, consistent with our diallel results. We favour this simple genetic control over an early-acting inbreeding depression (EID) explanation since none of our pollinations, successful or unsuccessful, resulted in partial embryo development, as would be expected under a whole genome EID effect.

scholarly journals Genes Involved in Sister Chromatid Separation and Segregation in the Budding Yeast Saccharomyces cerevisiae

Genetics ◽  
2001 ◽  
Vol 159 (2) ◽  
pp. 453-470
Author(s):  
Sue Biggins ◽  
Needhi Bhalla ◽  
Amy Chang ◽  
Dana L Smith ◽  
Andrew W Murray
Keyword(s):  
Chromosome Segregation ◽  
Sister Chromatid ◽  
Mitotic Spindle ◽  
Budding Yeast ◽  
Temperature Sensitive ◽  
Chromosome Behavior ◽  
Yeast Saccharomyces Cerevisiae ◽  
Sister Chromatids ◽  
Marked Chromosome ◽  
Sister Chromatid Separation

Abstract Accurate chromosome segregation requires the precise coordination of events during the cell cycle. Replicated sister chromatids are held together while they are properly attached to and aligned by the mitotic spindle at metaphase. At anaphase, the links between sisters must be promptly dissolved to allow the mitotic spindle to rapidly separate them to opposite poles. To isolate genes involved in chromosome behavior during mitosis, we microscopically screened a temperature-sensitive collection of budding yeast mutants that contain a GFP-marked chromosome. Nine LOC (loss of cohesion) complementation groups that do not segregate sister chromatids at anaphase were identified. We cloned the corresponding genes and performed secondary tests to determine their function in chromosome behavior. We determined that three LOC genes, PDS1, ESP1, and YCS4, are required for sister chromatid separation and three other LOC genes, CSE4, IPL1, and SMT3, are required for chromosome segregation. We isolated alleles of two genes involved in splicing, PRP16 and PRP19, which impair α-tubulin synthesis thus preventing spindle assembly, as well as an allele of CDC7 that is defective in DNA replication. We also report an initial characterization of phenotypes associated with the SMT3/SUMO gene and the isolation of WSS1, a high-copy smt3 suppressor.

Intergeneric hybrids of Hordeum vulgare with Agropyron caninum and A. dasystachyum

1985 ◽  
Vol 27 (4) ◽  
pp. 387-392 ◽  
Author(s):  
George Fedak
Keyword(s):  
Hordeum Vulgare ◽  
Chromosome Pairing ◽  
Meiotic Chromosome ◽  
Intergeneric Hybrids ◽  
Spindle Fibre ◽  
Chromosome Behavior ◽  
Paternal Parent ◽  
Agropyron Caninum

Hybrids were obtained by pollinating Hordeum vulgare cv. Betzes with Agropyron caninum (4x) and A. dasystachyum (4x) at frequencies of 1.4 and 6.1% of pollinated florets, respectively. The hybrids were sterile and phenotypically resembled the paternal parent, except for floret structure which was intermediate between the parental types. Chromosome pairing at meiosis was very low and thus provided no indication of homoeology between parental genomes. Abnormal meiotic chromosome behavior in meiocytes that occurred in sectors on the 'Betzes' × A. dasystachyum hybrid was attributed to abnormal spindle fibre function.Key words: intergeneric hybrids, Hordeum vulgare, Agropyron caninum, Agropyron dasystachyum.

Chromosome Behavior in Differentiation

2019 ◽  
pp. 86-91
Author(s):  
Archana Sharma ◽  
Sumithra Sen
Keyword(s):  
Chromosome Behavior

scholarly journals Genetic analysis of the claret locus of Drosophila melanogaster.

Genetics ◽  
1989 ◽  
Vol 123 (3) ◽  
pp. 511-524 ◽  
Author(s):  
W Sequeira ◽  
C R Nelson ◽  
P Szauter
Keyword(s):  
Drosophila Melanogaster ◽  
Single Gene ◽  
Chromosome Rearrangement ◽  
Overlapping Genes ◽  
Early Cleavage ◽  
Chromosome Behavior ◽  
Eye Color ◽  
Single Target ◽  
Radiation Induced ◽  
New Alleles

Abstract The claret (ca) locus of Drosophila melanogaster comprises two separately mutable domains, one responsible for eye color and one responsible for proper disjunction of chromosomes in meiosis and early cleavage divisions. Previously isolated alleles are of three types: (1) alleles of the claret (ca) type that affect eye color only, (2) alleles of the claret-nondisjunctional (cand) type that affect eye color and chromosome behavior, and (3) a meiotic mutation, non-claret disjunctional (ncd), that affects chromosome behavior only. In order to investigate the genetic structure of the claret locus, we have isolated 19 radiation-induced alleles of claret on the basis of the eye color phenotype. Two of these 19 new alleles are of the cand type, while 17 are of the ca type, demonstrating that the two domains do not often act as a single target for mutagenesis. This suggests that the two separately mutable functions are likely to be encoded by separate or overlapping genes rather than by a single gene. One of the new alleles of the cand type is a chromosome rearrangement with a breakpoint at the position of the claret locus. If this breakpoint is the cause of the mutant phenotype and there are no other mutations associated with the rearrangement, the two functions must be encoded by overlapping genes.

Chromosome behavior of heat shock induced triploid inFenneropenaeus chinensis

2003 ◽  
Vol 21 (3) ◽  
pp. 222-228 ◽  
Author(s):  
Zhang Xiaojun ◽  
Li Fuhua ◽  
Xiang Jianhai
Keyword(s):  
Heat Shock ◽  
Chromosome Behavior
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