scholarly journals Direct Evidence Of Sex In Symbiodiniaceae And A Hypothesis About Meiosis

2021 ◽  
Author(s):  
R.I. Figueroa ◽  
L. Howe-Kerr ◽  
A.M.S. Correa
Keyword(s):  
Nuclear Dna ◽  
Marine Invertebrates ◽  
Nuclear Dna Content ◽  
Indirect Evidence ◽  
Cytological Evidence ◽  
Direct Observations ◽  
Reef Degradation ◽  
The Family ◽  
Sexual Recombination

Abstract Dinoflagellates in the family Symbiodiniaceae are obligate endosymbionts of diverse marine invertebrates, including corals, and impact the capacity of their hosts to respond to climate change-driven ocean warming. Understanding the conditions under which increased genetic variation in Symbiodiniaceae arises via sexual recombination can support efforts to evolve thermal tolerance in these symbionts and ultimately mitigate coral bleaching, the breakdown of the coral-Symbiodiniaceae partnership under stress. However, direct observations of meiosis in Symbiodiniaceae have not been reported, despite various lines of indirect evidence that it occurs. We present the first cytological evidence of sex in Symbiodiniaceae based on nuclear DNA content and morphology using Image Flow Cytometry, Cell Sorting and Confocal Microscopy. We show Symbiodiniaceae cells undergo gamete conjugation, zygote formation and meiosis within a dominant reef-building coral in situ. On average, sex was detected in 1.5% of the cells analyzed (N=10.000-40.000 cells observed per sample in a total of 20 samples obtained from 3 coral colonies). We show that meiosis follows a two-step process described in other dinoflagellates, in which diploid zygotes form dyads during meiosis I and triads and tetrads as final products of meiosis II. This study sets the stage for investigating environmental triggers of Symbiodiniaceae sexuality and can accelerate the assisted evolution of a key coral symbiont in order to combat reef degradation.

scholarly journals Direct evidence of sex and a hypothesis about meiosis in Symbiodiniaceae

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. I. Figueroa ◽  
L. I. Howe-Kerr ◽  
A. M. S. Correa
Keyword(s):  
Nuclear Dna ◽  
Marine Invertebrates ◽  
Nuclear Dna Content ◽  
Indirect Evidence ◽  
Cytological Evidence ◽  
Direct Observations ◽  
Reef Degradation ◽  
The Family ◽  
Sexual Recombination

AbstractDinoflagellates in the family Symbiodiniaceae are obligate endosymbionts of diverse marine invertebrates, including corals, and impact the capacity of their hosts to respond to climate change-driven ocean warming. Understanding the conditions under which increased genetic variation in Symbiodiniaceae arises via sexual recombination can support efforts to evolve thermal tolerance in these symbionts and ultimately mitigate coral bleaching, the breakdown of the coral-Symbiodiniaceae partnership under stress. However, direct observations of meiosis in Symbiodiniaceae have not been reported, despite various lines of indirect evidence that it occurs. We present the first cytological evidence of sex in Symbiodiniaceae based on nuclear DNA content and morphology using Image Flow Cytometry, Cell Sorting and Confocal Microscopy. We show the Symbiodiniaceae species, Cladocopium latusorum, undergoes gamete conjugation, zygote formation, and meiosis within a dominant reef-building coral in situ. On average, sex was detected in 1.5% of the cells analyzed (N = 10,000–40,000 cells observed per sample in a total of 20 samples obtained from 3 Pocillopora colonies). We hypothesize that meiosis follows a two-step process described in other dinoflagellates, in which diploid zygotes form dyads during meiosis I, and triads and tetrads as final products of meiosis II. This study sets the stage for investigating environmental triggers of Symbiodiniaceae sexuality and can accelerate the assisted evolution of a key coral symbiont in order to combat reef degradation.

Determination of nuclear DNA content in fungi using mithramycin: vegetative diploidy in Armillaria mellea confirmed

1983 ◽  
Vol 29 (9) ◽  
pp. 1179-1183 ◽  
Author(s):  
A. L. Franklin ◽  
W. G. Filion ◽  
J. B. Anderson
Keyword(s):  
Dna Binding ◽  
Aspergillus Nidulans ◽  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Phytopathogenic Fungus ◽  
Armillaria Mellea ◽  
Dna Measurements

Armillaria mellea, a phytopathogenic fungus, is the only member of the Agaricales (Basidiomycetes) whose fertile vegetative phase in nature is thought to be diploid, rather than dikaryotic. To examine the vegetative ploidy of A. mellea, we used the DNA-binding antibiotic, mithramycin, for fluorometry of in situ nuclear DNA. The measurements of nuclear DNA content indicated that strains derived from single basidiospores of A. mellea were haploid and that strains derived from matings of isolates of single spores were diploid. These data confirm the results of earlier genetic experiments, which show haploidy and diploidy in unmated and mated strains, respectively. Nuclear DNA measurements in known haploid and diploid strains of Aspergillus nidulans confirmed the validity of our protocol.

Chromatin characterization by banding techniques, in situ hybridization, and nuclear DNA content in Cicer L. (Leguminosae)

Genome ◽  
1996 ◽  
Vol 39 (2) ◽  
pp. 258-265 ◽  
Author(s):  
I. Galasso ◽  
D. Pignone ◽  
M. Frediani ◽  
M. Maggiani ◽  
R. Cremonini
Keyword(s):  
In Situ Hybridization ◽  
Dna Content ◽  
Nuclear Dna ◽  
Hybrid Sterility ◽  
Nuclear Dna Content ◽  
5S Rdna ◽  
Rrna Genes ◽  
Evolutionary Pathway ◽  
C Banding

The karyotypes of three accessions, one each from three annual species of the genus Cicer, namely Cicer arietinum, Cicer reticulation, and Cicer echinospermum, were examined and compared using C-banding, the fluorochromes chromomycin A3, DAPI, and Hoechst 33258, in situ hybridization of the 18S–5.8S–25S and 5S rDNA sequences, and silver staining. The nuclear DNA content of the three species and the amount of heterochromatin were also determined. The results suggest an evolutionary pathway in which C. reticulatum is the ancestral species from which both C. arietinum and C. echinospermum are derived with the loss of one pair of satellites; subsequently, C. echinospermum further differentiated by the accumulation of chromosomal rearrangement(s) that gave rise to a hybrid sterility barrier. Key words : Cicer, C-banding, fluorochromes, Ag staining, rRNA genes.

Nuclear DNA content of lobular carcinoma in situ of the breast

Cancer ◽  
1973 ◽  
Vol 31 (6) ◽  
pp. 1553-1560 ◽  
Author(s):  
Arthur S. Ludwig ◽  
Takashi Okagaki ◽  
Ralph M. Richart ◽  
Raffaele Lattes
Keyword(s):  
Dna Content ◽  
Carcinoma In Situ ◽  
Nuclear Dna ◽  
Lobular Carcinoma ◽  
Nuclear Dna Content ◽  
Lobular Carcinoma In Situ

Genome multiplication is a generalised phenomenon in placentomal and interplacentomal trophoblast giant cells in cattle

2004 ◽  
Vol 16 (3) ◽  
pp. 301 ◽  
Author(s):  
Karl Klisch ◽  
Preben D. Thomsen ◽  
Vibeke Dantzer ◽  
Rudolf Leiser
Keyword(s):  
Dna Content ◽  
Nuclear Dna ◽  
In Situ Hybridisation ◽  
Nuclear Dna Content ◽  
Giant Cells ◽  
Crown Rump Length ◽  
Subsequent Determination ◽  
Trophoblast Giant Cells

The frequency of polyploidisation in bovine binucleate trophoblast giant cells (TGC) from placentomes (PL) and the interplacentomal allantochorion (AL) of six male fetuses with a crown–rump length between 3.5 and 103 cm was determined by in situ hybridisation with a chromosome-7-specific probe, using a probe specific for the Y chromosome to distinguish between maternal and fetal nuclei. The results showed that polyploid nuclei were essentially always of fetal origin. The frequency of tetraploid nuclei varied between 3% and 15% in both the placentomal and interplacentomal samples, with mean frequencies of 8.8% and 10.0% respectively. Octoploid nuclei were observed with a mean frequency of 1.1% in the interplacentomal samples, but were absent in samples from placentomes. Subsequent determination of nuclear DNA content by cytophotometric measurement of Feulgen-stained nuclei revealed that the frequency of nuclei with an 8C DNA content was several fold higher (AL 5.4%; PL 7.8%) than the frequency of octoploidy, suggesting that tetraploid TGC cells are arrested in the G2 phase of the cell cycle.

Peaceful revolution in genome size: polyploidy in the Nabidae (Heteroptera); autosomes and nuclear DNA content doubling

2020 ◽  
Author(s):  
David Sadílek ◽  
Jitka Vilímová ◽  
Tomáš Urfus
Keyword(s):  
Genome Size ◽  
X Chromosome ◽  
Dna Content ◽  
18S Rdna ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Chromosome Breakage ◽  
Polyploidy Event ◽  
First Time

Abstract Genome size and the position of 18S ribosomal DNA (rDNA) were analysed in two Himacerus, eight Nabis and two Prostemma species from the family Nabidae using flow cytometry and fluorescence in situ hybrization techniques. The karyotypes of Nabis biformis and Nabis maoricus, each with 2n = 16 + XY, and Prostemma aeneicolle, with 2n = 26 + XY, were recorded for the first time. All the species displayed one or two 18S rDNA signals on the X chromosome and up to two signals on the Y chromosome. Several females exhibited two different types of X chromosome breakage, namely within or outside of the 18S rDNA region. Measurements of nuclear DNA content revealed significant differences between all three genera under study. Most notably, the nuclear DNA content of Himacerus species, with 2n = 32/36 + XY (2C = 9–10 pg), was double that of Nabis species, with 2n = 16 + XY (2C = 4–6 pg). Therefore, the previously rejected theory of an autosomal polyploidy event in the evolution of the genus Himacerus is strongly supported by the results of the present study and is now being resurrected.

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