Cytological analysis of the male meiosis inPeriplaneta americana

1959 ◽  
Vol 56 (2) ◽  
pp. 281-287 ◽  
Author(s):  
G. P. Sharma ◽  
Ram Parshad ◽  
Prem Sehgal
Keyword(s):  
Male Meiosis ◽  
Cytological Analysis

scholarly journals Colchicine induced manifestation of abnormal male meiosis and 2n pollen in Trachyspermum ammi (L.) Sprague (Apiaceae)

Caryologia ◽  
2021 ◽  
Author(s):  
Harshita Dwivedi
Keyword(s):  
Morphological Analysis ◽  
Male Meiosis ◽  
Unreduced Gametes ◽  
2N Pollen ◽  
Cytological Analysis ◽  
Cytological Investigation ◽  
Drug Induced ◽  
Meiotic Restitution ◽  
Trachyspermum Ammi ◽  
Meiotic Aberrations

Unreduced gametes are the key source for the natural polyploidization in plants, but process of its formation is very low in nature. Meiotic mutants are second source for the formation of 2n pollen. In this cytological investigation, the meiotic aberrations and its impact on post-meiotic products were analysed in autotetraploid Trachyspermum ammi (L.) Sprague (4n=36). The seedlings of T. ammi (L.) Sprague were treated with 3 different concentrations of colchicine (0.2, 0.4 and 0.5%, w/v) for 3 different durations. Six polyploid plants were induced which was confirmed on the basis of cytological analysis. Colchicine, an anti-microtubular drug induced different meiotic and post-meiotic abnormalities such as chromosomal bridges, lagging chromosomes, scattering, precocious, fragments, dyads, triads, and polyads. The formation of several abnormal sporads clearly signifies the meiotic restitution. The tendency of univalents to scattered in the cytoplasm at metaphase was identified as a peculiar aberration asynapsis. Pollen variability and fusion of pollen walls was reported and pollen fertility was calculated. The morphological analysis of the pollen allowed us to confirm the occurrence of 2n pollen.

A CYTOGENETICAL ANALYSIS OF STERILE MUTANTS IN CAENORHABDITIS ELEGANS

1980 ◽  
Vol 22 (3) ◽  
pp. 391-403 ◽  
Author(s):  
Nicole Mounier ◽  
Jean Brun
Keyword(s):  
Caenorhabditis Elegans ◽  
Oocyte Maturation ◽  
Chromosome Pairing ◽  
Male Meiosis ◽  
Cytological Analysis ◽  
Wild Type ◽  
Nematode Caenorhabditis Elegans ◽  
The Third ◽  
Homozygous Mutant ◽  
Cytogenetical Analysis

The regulation of gametogenesis in the hermaphrodite and proterandrous nematode Caenorhabditis elegans is introduced here through the analysis of nonconditional sterile mutants. To investigate the mechanisms which allow the two gametogenetic phases to succeed each other in the same ovotestis, three mutants were studied cytogenetically. Two of the mutants exhibit only the spermatocyte phase and the third shows a greatly reduced and disturbed oogenesis. These three mutations all produce large decreases in ovotestis size and gonocyte number. Each of the three is monofactorial, recessive, autosomal and independent. Homozygous mutant males are also sterile. The gametogenesis phases which could be disturbed by mutation were determined by cytological analysis of the ovotestis of 12 other sterile strains. These phases occur during mitotic divisions of the genital primordium, zygotene chromosome pairing, male meiosis and spermiogenesis, oogenesis induction and oocyte maturation. These steps of gametogenesis need a wild-type genie activity to occur normally. It appears that spermatogenesis and oogenesis are two genetically independent processes, and that oogenesis is rather autonomous and its induction would depend on a hormonal factor.

CREATION OF THE INDUCED APPLE-THREE TETRAPLOIDS

1970 ◽  
pp. 23-25
Author(s):  
L. V. Tashmatova ◽  
О. V. Mantseva ◽  
N. V. Gorbacheva
Keyword(s):  
Environmental Conditions ◽  
Selection Process ◽  
Normal Growth ◽  
Cytological Analysis ◽  
Open Pollination ◽  
Apple Breeding ◽  
Adverse Environmental Conditions ◽  
Diploid Gametes ◽  
Resistance To Diseases

The basic moments of a process of obtaining apple tetraploids as donors of diploid gametes for apple breeding with polyploidy using are demonstrated. In industrial terms, triploids are of the greatest importance. The manifested effect of heterosis leads to the improvement of many characteristics - higher resistance to diseases, pests and adverse environmental conditions, greater autogamy than in diploids, less pronounced periodicity of fruiting, larger fruits and a convenient crown for harvesting. Triploids are developed as a result of crosses 2n × 3n or 2n × 4n. Tetraploids are necessary for more successful apple breeding with polyploidy using. For industry they are not of great importance but they are of interest as donors of diploid non-reduced gametes and allow to make the selection process more directional. One of the methods of experimental polyploidy is the induction of polyploids using mutagenes. The germs were treated with colchicines at concentrations 0.1% - 0.4% during 24 and 48 hours. According to the morphology the obtained plants were divided into five groups. Colchicine concentrations 0.3% and 0.4% during 48 hours of the treatment had a disastrous impact on the development of germs. As a result of the cytological analysis, tetraploids and chimeras were revealed, which were obtained from the seeds from the open pollination of Orlik and Svezhest (treatment variants – 0,1% colchicines solution and 24 and 48 hours of exposition), as well as from the seeds obtained as a result of the Svezhest × Bolotovskoye crossing. Tetraploids had a normal growth but they differed in large leaves, while chimeras were of low size with normal leaves and internodes.

scholarly journals Genetic Control of Mammalian Meiotic Recombination. I. Variation in Exchange Frequencies Among Males From Inbred Mouse Strains

Genetics ◽  
2002 ◽  
Vol 162 (1) ◽  
pp. 297-306 ◽  
Author(s):  
Kara E Koehler ◽  
Jonathan P Cherry ◽  
Audrey Lynn ◽  
Patricia A Hunt ◽  
Terry J Hassold
Keyword(s):  
Meiotic Recombination ◽  
Inbred Mouse ◽  
Inbred Strains ◽  
Male Meiosis ◽  
Mouse Strains ◽  
Recombination Rates ◽  
The Mean ◽  
Genetic Background Effects ◽  
Exchange Patterns ◽  
Positive Interference

AbstractGenetic background effects on the frequency of meiotic recombination have long been suspected in mice but never demonstrated in a systematic manner, especially in inbred strains. We used a recently described immunostaining technique to assess meiotic exchange patterns in male mice. We found that among four different inbred strains—CAST/Ei, A/J, C57BL/6, and SPRET/Ei—the mean number of meiotic exchanges per cell and, thus, the recombination rates in these genetic backgrounds were significantly different. These frequencies ranged from a low of 21.5 exchanges in CAST/Ei to a high of 24.9 in SPRET/Ei. We also found that, as expected, these crossover events were nonrandomly distributed and displayed positive interference. However, we found no evidence for significant differences in the patterns of crossover positioning between strains with different exchange frequencies. From our observations of >10,000 autosomal synaptonemal complexes, we conclude that achiasmate bivalents arise in the male mouse at a frequency of 0.1%. Thus, special mechanisms that segregate achiasmate chromosomes are unlikely to be an important component of mammalian male meiosis.

Secondary Tetrasomic Segregation of MDH-B and Preferential Pairing of Homeologues in Rainbow Trout

Genetics ◽  
1997 ◽  
Vol 145 (4) ◽  
pp. 1083-1092 ◽  
Author(s):  
Fred W Allendorf ◽  
Roy G Danzmann
Keyword(s):  
Allelic Variation ◽  
Male Meiosis ◽  
Proximal Region ◽  
Stage Model ◽  
Preferential Pairing ◽  
Homologous Chromosomes ◽  
Tetrasomic Inheritance ◽  
Segregation Ratios ◽  
Homeologous Chromosomes ◽  
Duplicated Loci

We examined the inheritance of allelic variation at an isozyme locus, MDH-B, duplicated by ancestral polyploidy in salmonid fishes. We detected only disomic segregation in females. Segregation ratios in males were best explained by a mixture of disomic and tetrasomic inheritance. We propose a two-stage model of pairing in male meiosis in which, first, homologous chromosomes pair and recombine in the proximal region of the chromosome. Next, homeologous chromosomes pair and recombine distally. We suggest that this type of tetrasomic inheritance in which centromeres segregate disomically should be referred to as “secondary tetrasomy” to distinguish it from tetrasomy involving entire chromosomes (i.e., “primary tetrasomy”). Differences in segregation ratios between males indicate differences between individuals in the amount of recombination between homeologous chromosomes. We also consider the implication of these results for estimation of allele frequencies at duplicated loci in salmonid populations.

scholarly journals Male meiosis and pollen morphology in diploid Indonesian wild bananas and cultivars

The Nucleus ◽  
2021 ◽  
Author(s):  
Fajarudin Ahmad ◽  
Yuyu S. Poerba ◽  
Gert H. J. Kema ◽  
Hans de Jong
Keyword(s):  
Hybrid Sterility ◽  
Pollen Grains ◽  
Chromosome Analysis ◽  
Male Meiosis ◽  
Enzyme Treatment ◽  
Unreduced Gamete ◽  
Ploidy Levels ◽  
Scientific Disciplines ◽  
Sterile Pollen ◽  
Mother Cells

AbstractBreeding of banana is hampered by its genetic complexity, structural chromosome rearrangements and different ploidy levels. Various scientific disciplines, including cytogenetics, linkage mapping, and bioinformatics, are helpful tools in characterising cultivars and wild relatives used in crossing programs. Chromosome analysis still plays a pivotal role in studying hybrid sterility and structural and numerical variants. In this study, we describe the optimisation of the chromosome spreading protocol of pollen mother cells focusing on the effects of standard fixation methods, duration of the pectolytic enzyme treatment and advantages of fluorescence microscopy of DAPI stained cell spreads. We demonstrate the benefits of this protocol on meiotic features of five wild diploid Musa acuminata bananas and a diploid (AA) cultivar banana “Rejang”, with particular attention on pairing configurations and chromosome transmission that may be indicative for translocations and inversions. Pollen slides demonstrate regular-shaped spores except “Rejang”, which shows fertile pollen grains of different size and sterile pollen grains, suggesting partial sterility and unreduced gamete formation that likely resulted from restitutional meiotic divisions.

A role of the Drosophila homeless gene in repression of Stellate in male meiosis

Chromosoma ◽  
2001 ◽  
Vol 110 (3) ◽  
pp. 228-240 ◽  
Author(s):  
Wendy Stapleton ◽  
Suchita Das ◽  
Bruce D. McKee
Keyword(s):  
Male Meiosis

Metabolic profiling and cytological analysis of proanthocyanidins in immature seeds of Arabidopsis thaliana flavonoid accumulation mutants

2010 ◽  
Vol 62 (4) ◽  
pp. 549-559 ◽  
Author(s):  
Satoshi Kitamura ◽  
Fumio Matsuda ◽  
Takayuki Tohge ◽  
Keiko Yonekura-Sakakibara ◽  
Mami Yamazaki ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Metabolic Profiling ◽  
Cytological Analysis ◽  
Immature Seeds ◽  
Flavonoid Accumulation

Fine structure of the kinetochores in six species of the Coleoptera

Genome ◽  
1997 ◽  
Vol 40 (3) ◽  
pp. 379-385
Author(s):  
Klaus Werner Wolf
Keyword(s):  
Direct Contact ◽  
Karyotype Evolution ◽  
Coccinella Septempunctata ◽  
Cell Types ◽  
Male Meiosis ◽  
Serial Sections ◽  
Cell Type ◽  
Present Survey ◽  
Transmission Electron ◽  
Size Variability

Kinetochore structure was examined in a total of 6 species from 5 different families of the Coleoptera using transmission electron microscopy of ultrathin serial sections. Metaphase spermatogonia and primary and secondary spermatocytes were studied in Tenebrio molitor (Tenebrionidae) to determine whether kinetochore structure varies depending on the cell type. In all three cell types, the kinetochore microtubules (MTs) were in direct contact with the chromosomal surface, and kinetochore plates were not detectable. In the other species, only metaphase I spermatocytes were examined. As in T. molitor, distinct kinetochore plates were also absent in Adelocera murina (Elateridae), Agapanthia villosoviridescens (Cerambycidae), and Coccinella septempunctata (Coccinellidae). However, bivalents in male meiosis of two representatives of the Chrysomelidae, Agelastica alni and Chrysolina graminis, showed roughly spherical kinetochores at their poleward surfaces. Microtubules were in contact with this material. Thus, although the present survey covers only a small number of species, it is clear that at least two kinetochore types occur in the Coleoptera. The cytological findings are discussed in the context of chromosome number and genome size variability in the Coleopteran families studied. It is suggested that properties of the kinetochores could play a role in karyotype evolution in the Coleoptera.Key words: bivalent, microtubule, meiosis, metaphase, spermatocyte.

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