Non-random segregation of gene I for Fusarium resistance in the tomato

Abstract A fundamental principle of Mendelian inheritance is random segregation of alleles to progeny; however, examples of distorted transmission either of specific alleles or of whole chromosomes have been described in a variety of species. In humans and mice, a distortion in chromosome transmission is often associated with a chromosome abnormality. One such example is the fertile XO female mouse. A transmission distortion effect that results in an excess of XX over XO daughters among the progeny of XO females has been recognized for nearly four decades. Utilizing contemporary methodology that combines immunofluorescence, FISH, and three-dimensional confocal microscopy, we have readdressed the meiotic segregation behavior of the single X chromosome in oocytes from XO females produced on two different inbred backgrounds. Our studies demonstrate that segregation of the univalent X chromosome at the first meiotic division is nonrandom, with preferential retention of the X chromosome in the oocyte in ∼60% of cells. We propose that this deviation from Mendelian expectations is facilitated by a spindle-mediated mechanism. This mechanism, which appears to be a general feature of the female meiotic process, has implications for the frequency of nondisjunction in our species.

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Mutational Analysis of the Drosophila Sister-Chromatid Cohesion Protein ORD and Its Role in the Maintenance of Centromeric Cohesion

Genetics ◽

10.1093/genetics/146.4.1319 ◽

1997 ◽

Vol 146 (4) ◽

pp. 1319-1331 ◽

Cited By ~ 1

Author(s):

Sharon E Bickel ◽

Dudley W Wyman ◽

Terry L Orr-Weaver

Keyword(s):

Sister Chromatid ◽

Mutational Analysis ◽

Germ Line ◽

Sister Chromatid Cohesion ◽

Chromosome Loss ◽

Male And Female ◽

Chromatid Cohesion ◽

Random Segregation ◽

Kinetochore Function ◽

Segregation Of Chromosomes

The ord gene is required for proper segregation of all chromosomes in both male and female Drosophila meiosis. Here we describe the isolation of a null ord allele and examine the consequences of ablating ord function. Cytologically, meiotic sister-chromatid cohesion is severely disrupted in flies lacking ORD protein. Moreover, the frequency of missegregation in genetic tests is consistent with random segregation of chromosomes through both meiotic divisions, suggesting that sister cohesion may be completely abolished. However, only a slight decrease in viability is observed for ord null flies, indicating that ORD function is not essential for cohesion during somatic mitosis. In addition, we do not observe perturbation of germ-line mitotic divisions in flies lacking ORD activity. Our analysis of weaker ord alleles suggests that ORD is required for proper centromeric cohesion after arm cohesion is released at the metaphase I/anaphase I transition. Finally, although meiotic cohesion is abolished in the ord null fly, chromosome loss is not appreciable. Therefore, ORD activity appears to promote centromeric cohesion during meiosis II but is not essential for kinetochore function during anaphase.

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IN-VITRO SELECTION FOR FUSARIUM-RESISTANCE IN GLADIOLUS

Acta Horticulturae ◽

10.17660/actahortic.1997.430.96 ◽

1997 ◽

pp. 605-610 ◽

Cited By ~ 1

Author(s):

P.C. Remotti ◽

M.J. van Harmelen ◽

H.J.M. Löffler

Keyword(s):

In Vitro Selection ◽

Fusarium Resistance ◽

Selection For

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Release of Pea Germplasm with Fusarium Resistance Combined with Desirable Yield and Anti-Lodging Traits

Journal of Plant Registrations ◽

10.3198/jpr2013.07.0041crg ◽

2014 ◽

Vol 8 (2) ◽

pp. 191-194 ◽

Cited By ~ 8

Author(s):

Lyndon D. Porter ◽

John M. Kraft ◽

Niklaus J. Grünwald

Keyword(s):

Fusarium Resistance

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Ubiquitin and fusarium resistance: Lessons from wheat cDNAS conferring deoxynivalenol resistance in yeast

Cereal Research Communications ◽

10.1556/crc.36.2008.suppl.b.37 ◽

2008 ◽

Vol 36 (Supplement 6) ◽

pp. 437-441 ◽

Cited By ~ 3

Author(s):

Doris Lucyshyn ◽

Shamsozoha Abolmaali ◽

Hanna Weindorfer ◽

Mehrdad Shams ◽

Gerlinde Wiesenberger ◽

...

Keyword(s):

Fusarium Resistance

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The asymmetry of female meiosis reduces the frequency of inheritance of unpaired chromosomes

eLife ◽

10.7554/elife.06056 ◽

2015 ◽

Vol 4 ◽

Cited By ~ 19

Author(s):

Daniel B Cortes ◽

Karen L McNally ◽

Paul E Mains ◽

Francis J McNally

Keyword(s):

Caenorhabditis Elegans ◽

X Chromosome ◽

High Frequency ◽

Germ Line ◽

Extra Chromosome ◽

Polar Body ◽

Contractile Ring ◽

Female Meiosis ◽

Random Segregation ◽

The Asymmetry

Trisomy, the presence of a third copy of one chromosome, is deleterious and results in inviable or defective progeny if passed through the germ line. Random segregation of an extra chromosome is predicted to result in a high frequency of trisomic offspring from a trisomic parent. Caenorhabditis elegans with trisomy of the X chromosome, however, have far fewer trisomic offspring than expected. We found that the extra X chromosome was preferentially eliminated during anaphase I of female meiosis. We utilized a mutant with a specific defect in pairing of the X chromosome as a model to investigate the apparent bias against univalent inheritance. First, univalents lagged during anaphase I and their movement was biased toward the cortex and future polar body. Second, late-lagging univalents were frequently captured by the ingressing polar body contractile ring. The asymmetry of female meiosis can thus partially correct pre-existing trisomy.

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A Radioautographic Study of the time Course of Male Meiosis in the Newt Triturus Vulgaris

Journal of Cell Science ◽

10.1242/jcs.3.4.615 ◽

1968 ◽

Vol 3 (4) ◽

pp. 615-626

Author(s):

H. G. CALLAN ◽

J. H. TAYLOR

Keyword(s):

Time Course ◽

Male Meiosis ◽

S Phase ◽

Triturus Vulgaris ◽

Random Segregation ◽

Label Distribution

In male Triturus vulgaris at 16 °C the pre-meiotic synthesis of DNA (S-phase) takes 9-10 days. The S-phase starts 1-2 days after completion of the ultimate spermatogonial mitosis, and extends into leptotene. Heterochromatic regions, most of which lie close to the centromeres, start and finish replicating about 1 day later than other parts of the chromosomes. Synapsis starts 6 days after the end of pre-meiotic S and is completed 8 days later. Pachytene lasts for 4 or 5 days, diplotene for 1 or 2 days, and first metaphase occurs 20 or 21 days after the end of pre-meiotic S. Label distribution at first metaphase in spermatocytes stemming from spermatogonia which incorporated [3H]thymidine during the penultimate intermitotic S shows that random segregation and assortment of labelled and unlabelled chromatids took place at the ultimate spermatogonial mitosis.

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