Meiotic behaviour of 11 primary trisomics in diploid potato and its consequences for the transmission of the extra chromosome

Genome ◽  
1995 ◽  
Vol 38 (1) ◽  
pp. 17-26 ◽  
Author(s):  
M. Wagenvoort
Keyword(s):  
Solanum Tuberosum L ◽  
Extra Chromosome ◽  
Relative Length ◽  
Genotypic Differences ◽  
Primary Trisomics ◽  
The Absolute ◽  
Mother Cells ◽  
Almost All ◽  
Chromosome Segments ◽  
Metaphase I

Meiosis was studied in 11 primary trisomics (2n = 2x + 1 = 25) from diploid Solanum tuberosum L. ssp. tuberosum Hawkes (2n = 2x = 24) and from interspecific Solanum hybrids. The three homologous chromosomes were associated in a trivalent in 90% of more than 175 pollen mother cells analysed at pachytene. Trivalents showing a two by two pairing and partner exchanges at pachytene along with incomplete triple synapsis were frequently observed. Foldback pairing, predominantly observed in the heterochromatic parts of the chromosomes, occurred in 28.3% of the trivalents. Nonhomologous association of chromosome segments was observed in 29.1% of the trivalents. Up to six telomeres were associated homologously in 46.2% of the trivalents. Genotypic differences with respect to trivalent formation at metaphase I occurred in almost all the trisomic types and was significant for the trisomics for chromosomes 4, 7, and 9. The coefficient of realization of a trivalent (CRT) at metaphase I in the 11 primary trisomics varied from 0.20 to 0.80, and was positively correlated with the absolute length of the extra chromosome (r = 0.61, p ≤ 0.05) and with the absolute, as well as the relative, length of the euchromatic segments of the extra chromosome (r = 0.70, p ≤ 0.05). There was no apparent relationship between the CRT and the distribution pattern at anaphase I or anaphase II. The rate of female transmission of the extra chromosome varied from 10.0 to 44.6% among different trisomics. For chromosomes 4, 7, and 9, this rate differed significantly among genotypes of the same trisomic.Key words: primary trisomics, meiosis, nonhomologous chromosome association, telomere pairing, triple synapsis, female transmission, Solanum.

Spontaneous structural rearrangements in Solanum phureja Juz. et Buk. 2. Meiotic behaviour and identification of interchange chromosomes using primary trisomics

Genome ◽  
1995 ◽  
Vol 38 (1) ◽  
pp. 140-147
Author(s):  
M. Wagenvoort
Keyword(s):  
Pollen Mother Cell ◽  
Mother Cell ◽  
Solanum Phureja ◽  
Chromosome Identification ◽  
Structural Rearrangements ◽  
Primary Trisomics ◽  
Interchange Heterozygote ◽  
Mother Cells ◽  
I Cells ◽  
Metaphase I

Meiosis was studied in two diploid (2n = 2x = 24) siblings of Solanum phureja Juz. et Buk. and in 11 disomic and 2 trisomic descendants. The diploid siblings carry the same heterozygous interchange and either one or two inversions. The frequency of quadrivalents at diakinesis/metaphase I in these clones was 0.56 and 0.62 per pollen mother cell. In two plants from the first inbred generation (I1) this frequency was about the same but in some other I1 plants and a full sib the frequency was substantially lower, varying from 0.00 to 0.16. Most quadrivalents, 78–83%, were rings. A variety of quadrivalent configurations at diakinesis and metaphase I was observed, giving rise to balanced and unbalanced gametes. The absence of ring quadrivalents in trisomic descendants of one of the siblings implied that tertiary trisomics or primaries being homozygous for the interchange were present in the I1 generation. Regular chromosome distribution (12–12) at anaphase I occurred in 46.5 and 73.2% of the pollen mother cells studied in the two original clones. Irregularities, such as 11–13 distribution, lagging chromosomes, and a bridge and fragment, were detected on average in 2.7, 3.3, and 32.5%, respectively, of the anaphase I cells analysed. In hybrids from crosses between 6 primary trisomics as females with the interchange heterozygote, the involvement in the interchange of chromosomes 3 and 12 was clearly demonstrated.Key words: Solanum phureja, interchange heterozygote, chromosome identification, interchange trisomic, meiosis.

C-banding and fluorescence in situ hybridization studies of the wheat–alien hybrid 'Agrotana'

Genome ◽  
1994 ◽  
Vol 37 (3) ◽  
pp. 477-481 ◽  
Author(s):  
Jie Xu ◽  
R. L. Conner ◽  
A. Laroche
Keyword(s):  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Genomic Dna ◽  
Chromosome Engineering ◽  
C Banding ◽  
Chinese Spring Wheat ◽  
Mother Cells ◽  
Alien Chromatin ◽  
Chromosome Segments

'Agrotana', a wheat-alien hybrid (2n = 56), is a potential source of resistance to common root rot, stem rust, wheat streak mosaic virus, and the wheat curl mite. However, the origin of 'Agrotana', reported to be durum wheat × Agropyron trichophorum (pubescent wheatgrass), is uncertain. The objective of this investigation was to determine the chromosome constitution of 'Agrotana' using C-banding and fluorescence in situ hybridization techniques. The F1 hybrid of 'Agrotana' × 'Chinese Spring' wheat showed 7 I + 21 II in 14.9% of the pollen mother cells, evidence of the presence of the A, B, and D genomes in 'Agrotana'. The hybrid had 16 heavily C-banded chromosomes, namely 4A, and 1-7B of wheat, and a translocation that probably involved wheat chromosomes 2A and 2D. In situ hybridization using biotinylated genomic DNA of Ag. trichophorum cv. Greenleaf blocked with CS DNA failed to identify the alien chromosomes in 'Agrotana', indicating that the alien chromosomes were not likely derived from pubescent wheatgrass. In situ hybridization using labelled wheat genomic DNA blocked with 'Agrotana' DNA revealed that 'Agrotana' had 40 wheat, 14 alien, and 2 (a pair) wheat–alien translocated chromosomes. There was no homology between wheat and the alien chromosomes or chromosome segments involved in the wheat–alien recombinant. Two of the seven pairs of alien chromosomes were homoeologous to each other. The ability to identify alien chromatin in wheat using labelled wheat DNA instead of labelled alien DNA will be particularly useful in chromosome engineering of wheat germplasms having alien chromatin of unknown origin.Key words: wheat–alien hybrid, C-banding, fluorescence in situ hybridization, labelled wheat DNA as probe.

scholarly journals On the appendicular skeleton of the primates

1867 ◽  
Vol 15 ◽  
pp. 320-321
Keyword(s):  
Relative Size ◽  
Relative Length ◽  
Appendicular Skeleton ◽  
Pelvic Limb ◽  
The Absolute

The author began by mentioning the principal variations found in the order Primates, as to the absolute and relative length of the pectoral limb with and without the manus; and then taking each bone separately, described the modifications undergone by each in all the genera of the order; as also the relative size of the segments and bones of the limb compared to each other and to the spine. The pelvic limb was then similarly treated of, and, in addition, its segments and bones were compared with the homo-typal segments and bones of the pectoral limb. The author after this reconsidered the question as to the use of the terms “hand” and “foot,” and the applicability of the term “Quadru-manous” to Apes and Lemuroids.

Analysis of the mechanism(s) of metaphase I arrest in strain LT mouse oocytes: participation of MOS

Development ◽  
1997 ◽  
Vol 124 (24) ◽  
pp. 5107-5113
Author(s):  
Y. Hirao ◽  
J.J. Eppig
Keyword(s):  
Potential Role ◽  
Inbred Strains ◽  
Mitogen Activated Protein Kinase ◽  
Null Mutation ◽  
Mitogen Activated Protein ◽  
Cytostatic Factor ◽  
Almost All ◽  
Dependent Mechanism ◽  
Metaphase I

Oocytes of almost all vertebrates become arrested at metaphase II to await fertilization. Arrest is achieved with the participation of a protein complex known as cytostatic factor (CSF) that stabilizes histone H1 kinase activity. MOS and mitogen-activated protein kinase (MAPK) are important components of CSF. Strain LT/Sv mice, and strains related to LT/Sv, produce a high percentage of atypical oocytes that are arrested at metaphase I when normal oocytes have progressed to metaphase II. The potential role of MOS in metaphase I arrest was investigated using strain LT/Sv and LT-related recombinant inbred strains, LTXBO and CX8-4. MOS and MAPK are produced and functional in maturing LT oocytes. Two experimental paradigms were used to reduce or delete MOS in LT oocytes and assess effects on metaphase I arrest. First, sense and antisense Mos oligonucleotides were microinjected into metaphase I-arrested oocytes. Antisense, but not sense, Mos oligonucleotides promoted the activation of metaphase I-arrested oocytes. Second, mice carrying a Mos null mutation were crossed with LT mice, the null mutation was backcrossed three times to LT mice, and Mos(+/−) N3 mice were intercrossed to produce Mos(−/−), Mos(+/−) and Mos(+/+) N3F1 mice. Oocytes of all three Mos genotypes of N3F1 mice sustained meiotic arrest for 17 hours indicating that metaphase I arrest is not initiated by a MOS-dependent mechanism. However, unlike Mos(+/+) and Mos(+/−) CX8-4 N3F1 oocytes, metaphase I arrest of Mos(−/−) CX8-4 N3F1 oocytes was not sustained after 17 hours and became reversed gradually. These results, like the antisense Mos oligonucleotide microinjection experiments, suggest that MOS participates in sustaining metaphase I arrest in LT oocytes.

scholarly journals Comprehensive Comparative Genomics and Phenotyping of Methylobacterium Species

2021 ◽  
Vol 12 ◽  
Author(s):  
Ola Alessa ◽  
Yoshitoshi Ogura ◽  
Yoshiko Fujitani ◽  
Hideto Takami ◽  
Tetsuya Hayashi ◽  
...  
Keyword(s):  
Comparative Genomics ◽  
Phylogenetic Relationship ◽  
Distinct Species ◽  
Genotypic Differences ◽  
Clade C ◽  
Single Genus ◽  
Almost All ◽  
Type Strains ◽  
Dependent Pathway ◽  
Insight Into

The pink-pigmented facultative methylotrophs (PPFMs), a major bacterial group found in the plant phyllosphere, comprise two genera: Methylobacterium and Methylorubrum. They have been separated into three major clades: A, B (Methylorubrum), and C. Within these genera, however, some species lack either pigmentation or methylotrophy, which raises the question of what actually defines the PPFMs. The present study employed a comprehensive comparative genomics approach to reveal the phylogenetic relationship among the PPFMs and to explain the genotypic differences that confer their different phenotypes. We newly sequenced the genomes of 29 relevant-type strains to complete a dataset for almost all validly published species in the genera. Through comparative analysis, we revealed that methylotrophy, nitrate utilization, and anoxygenic photosynthesis are hallmarks differentiating the PPFMs from the other Methylobacteriaceae. The Methylobacterium species in clade A, including the type species Methylobacterium organophilum, were phylogenetically classified into six subclades, each possessing relatively high genomic homology and shared phenotypic characteristics. One of these subclades is phylogenetically close to Methylorubrum species; this finding led us to reunite the two genera into a single genus Methylobacterium. Clade C, meanwhile, is composed of phylogenetically distinct species that share relatively higher percent G+C content and larger genome sizes, including larger numbers of secondary metabolite clusters. Most species of clade C and some of clade A have the glutathione-dependent pathway for formaldehyde oxidation in addition to the H4MPT pathway. Some species cannot utilize methanol due to their lack of MxaF-type methanol dehydrogenase (MDH), but most harbor an XoxF-type MDH that enables growth on methanol in the presence of lanthanum. The genomes of PPFMs encode between two and seven (average 3.7) genes for pyrroloquinoline quinone-dependent alcohol dehydrogenases, and their phylogeny is distinctly correlated with their genomic phylogeny. All PPFMs were capable of synthesizing auxin and did not induce any immune response in rice cells. Other phenotypes including sugar utilization, antibiotic resistance, and antifungal activity correlated with their phylogenetic relationship. This study provides the first inclusive genotypic insight into the phylogeny and phenotypes of PPFMs.

Trends in the population of the Northern Hairy-nosed Wombat Lasiorhinus krefftii in Epping Forest National Park, Central Queensland

1994 ◽  
Vol 1 (2) ◽  
pp. 141 ◽  
Author(s):  
Doug G. Crossman ◽  
Christopher N. Johnsow ◽  
Alan B. Horsup
Keyword(s):  
National Park ◽  
Absolute Size ◽  
Forest Region ◽  
Prolonged Drought ◽  
Males And Females ◽  
The Absolute ◽  
The Stability ◽  
Almost All

The Northern Hairy-nosed Wombat Lasiorhinus krefftii now survives only in Epping Forest National Park, central Queensland. The species was formerly more widespread in the Epping Forest region than at present. Its decline appears to have occurred in three distinct episodes of contraction, two of which were associated with prolonged drought. Indirect monitoring of abundance suggests that the population was stable from 1974 to 1981, when cattle were excluded from the Park, but has increased since 1983. A trapping programme between 1985 and 1989 suggests that the absolute size of the population may be about 70. The population contains approximately equal numbers of males and females; almost all females breed; and a large and apparently increasing proportion of the population consists of young animals. Further increases in density and range within Epping Forest National Park appear possible. Removal of some animals for translocation should be attempted when it is clear that such removals will not jeopardize the stability and vigour of the Epping Forest population.

GENETICS OF A PRIMARY TRISOMIC SERIES IN BARLEY: IDENTIFICATION BY PROTEIN ELECTROPHORESIS

1970 ◽  
Vol 12 (3) ◽  
pp. 490-495 ◽  
Author(s):  
R. G. McDaniel ◽  
R. T. Ramage
Keyword(s):  
Extra Chromosome ◽  
Seed Proteins ◽  
Disc Electrophoresis ◽  
Protein Electrophoresis ◽  
Primary Trisomics

Disc electrophoresis of seed proteins identified the extra chromosome involved in primary trisomics of barley. Each of the seven primary trisomics could be distinguished from diploids and from each other. Electrophoresis provided a precise biochemical criterion for identification of trisomics.

Genome constitution of the Australian hexaploid grass Elymus scabrus (Poaceae: Triticeae)

Genome ◽  
1993 ◽  
Vol 36 (1) ◽  
pp. 147-151 ◽  
Author(s):  
J. Torabinejad ◽  
R. J. Mueller
Keyword(s):  
Chromosome Pairing ◽  
Interspecific Hybrids ◽  
Intergeneric Hybrid ◽  
Meiotic Pairing ◽  
Genome Constitution ◽  
Psathyrostachys Juncea ◽  
Hybrid Plants ◽  
Thinopyrum Bessarabicum ◽  
Mother Cells ◽  
Metaphase I

Eight intergeneric hybrid plants were obtained between Elymus scabrus (2n = 6x = 42, SSYY??) and Australopyrum pectinatum ssp. retrofractum (2n = 2x = 14, WW). The hybrids were vegetatively vigorous but reproductively sterile. Examination of pollen mother cells at metaphase I revealed an average of 16.63 I, 5.29 II, 0.19 III, and 0.05 IV per cell for the eight hybrids. The average chiasma frequency of 6.77 per cell in the above hybrids strongly supports the presence of a W genome from A. pectinatum ssp. retrofractum in E. scabrus. Meiotic pairing data of some other interspecific hybrids suggest the existence of the SY genomes in E. scabrus. Therefore, the genome constitution of E. scabrus should be written as SSYYWW. Two other hybrid plants resulted from Elymus yezoensis (2n = 4x = 28, SSYY) crosses with A. pectinatum ssp. pectinatum (2n = 2x = 14, WW). Both were weak and sterile. An average of 0.45 bivalents per cell were observed at metaphase I. This clearly indicates a lack of pairing between W genome of Australopyrum and S or Y genomes of E. yezoensis. In addition, six hybrid plants of E. scabrus with Psathyrostachys juncea (2n = 2x = 14, NN) and one with Thinopyrum bessarabicum (2n = 2x = 14, JJ) were also obtained. The average bivalents per cell formed in both combinations were 2.84 and 0.70, respectively. The results of the latter two combinations showed that there is no N or J genome in E. scabrus.Key words: wide hybridization, chromosome pairing, genome analysis, Australopyrum, Elymus.

Existence of host-related DNA sequences in the schistosome genome

Parasitology ◽  
1991 ◽  
Vol 102 (3) ◽  
pp. 397-403 ◽  
Author(s):  
Y. Iwamura ◽  
Y. Irie ◽  
R. Kominami ◽  
T. Nara ◽  
K. Yasuraoka
Keyword(s):  
Dna Sequences ◽  
Extra Chromosome ◽  
Repetitive Sequences ◽  
Dna Fingerprints ◽  
Alu Sequence ◽  
Type C ◽  
Almost All ◽  
Intracisternal A Particle

DNA sequences homologous to the mouse intracisternal A particle and endogenous type C retrovirus were detected in the DNAs ofSchistosoma japonicumadults andS. mansonieggs. Furthermore, other kinds of repetitive sequences in the host genome such as mouse type 1 Alu sequence (B1), mouse type 2 Alu sequence (B2) and mo-2 sequence, a mouse mini-satellite, were also detected in the DNAs from adults and eggs ofS. japonicumand eggs ofS. mansoni. Almost all of the sequences described above were absent in the DNAs ofS. mansoniadults. The DNA fingerprints of schistosomes, using the mo-2 sequence, were indistinguishable from each other and resembled those of their murine hosts. Moreover, the mo-2 sequence was hypermethylated in the DNAs of schistosomes and its amount was variable in them. These facts indicate that host-related sequences are actually present in schistosomes and that the mo-2 repetitive sequence exists probably in extra-chromosome.

Two potato (Solanum tuberosum) varieties differ in drought tolerance due to differences in root growth at depth

2014 ◽  
Vol 41 (11) ◽  
pp. 1107 ◽  
Author(s):  
Jaime Puértolas ◽  
Carlos Ballester ◽  
E. David Elphinstone ◽  
Ian C. Dodd
Keyword(s):  
Solanum Tuberosum ◽  
Drought Tolerance ◽  
Root Growth ◽  
Water Deficit ◽  
Solanum Tuberosum L ◽  
Shoot Biomass ◽  
Genotypic Differences ◽  
Deep Soil ◽  
Soil Layers ◽  
Cultural Conditions

To test the hypothesis that root growth at depth is a key trait explaining some genotypic differences in drought tolerance in potato (Solanum tuberosum L.), two varieties (Horizon and Maris Piper) differing in drought tolerance were subjected to different irrigation regimes in pots in a glasshouse and in the field under a polytunnel. In the glasshouse, both cultivars showed similar gas exchange, leaf water potential, leaf xylem ABA concentration and shoot biomass independently of whether plants were grown under well watered or water deficit conditions. Under well watered conditions, root growth was three-fold higher in Horizon compared with Maris Piper, 3 weeks after emergence. Water deficit reduced this difference. In the polytunnel, applying 60% or less irrigation volume compared with full irrigation significantly decreased tuber yield in Maris Piper but not in Horizon. This was coincident with the higher root density of Horizon in deep soil layers (>40 cm), where water content was stable. The results suggest that early vigorous root proliferation may be a useful selection trait for maintaining yield of potato under restricted irrigation or rainfall, because it rapidly secures access to water stored in deep soil layers. Although selecting for vigorous root growth may assist phenotyping screening for drought tolerance, these varieties may require particular environmental or cultural conditions to express root vigour, such as sufficiently deep soils or sufficient water shortly after emergence.

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