نتایج جستجو برای: chromosomes counting

تعداد نتایج: 107370  

Journal: :Agrarnaâ nauka 2023

Relevance. The main purpose of micronuclear analysis is to identify substances that cause cytotoxic damage and lead the formation micronuclei containing lagging fragments chromosomes or whole chromosomes. For study chromosomal disorders, now very often used, since it quite easy perform does not require large costs. Methods results. Micronuclei are cytoplasmic chromatin-containing bodies formed ...

ژورنال: :مجله گیاهشناسی ایران 1999
سیده باهره جوادی سید محمد غفاری

بخش sphaerocephalae یکی از بخشهایی کوچک جنس cousinia است، که در غرب آسیا پراکندگی دارد. مطالعات کروموزومی روی چهار گونه از این بخش توضیح داده شده است. تمام گونه ها دارای تقسیم میوز منظم و شامل 13 جفت کروموزوم بودند. گونهxiphiolepis  c. علاوه بر 13 جفت کروموزوم دارای صفر الی سه کروموزوم b بود. به نظر می رسد که عدد پایه کروموزومی بخش x=13 باشد.

1999
N. Sari K. Abak M. Pitrat

Direct (chromosome counting) and indirect (flow cytometry, stomatal size, chloroplast number of the guard cells and morphological observations) methods were tested in order to determine the ploidy levels of haploid and diploid watermelon plants of the cultivars Sugar Baby and Halep Karasi. The results revealed that all the techniques tested can be used successfully. It was determined that while...

Journal: :Cell 2006

In this issue's Cell Biology Select, we discuss recent findings in the field of nuclear organization. We focus on studies that describe potential functions for physical interactions among chromosomes, interactions between DNA elements and the nuclear envelope, and the dynamics of chromatin. Organisms have different ways of compensating for unequal gene dosage between the sexes. In female mammal...

Journal: :International journal of clinical and experimental pathology 2015
Yong-Hua Shi Bo-Wei Wang Talaf Tuokan Qiao-Zhi Li Ya-Jing Zhang

A micronucleus is an additional small nucleus formed due to chromosomes or chromosomal fragments fail to be incorporated into the nucleus during cell division. In this study, we assessed the utility of micronucleus counting as a screening tool in cervical precancerous lesions in Thinprep cytological test smears under oil immersion. High risk HPV was also detected by hybrid capture-2 in Thinprep...

1996
Hans Netten Lucas J van Vliet Hans Vrolijk Willem C R Sloos Hans J Tanke Ian T Young

Fluorescence in situ hybridization allows the enumeration of chromosomal abnormalities in interphase cell nuclei. This process is called dot counting. To estimate the distribution of chromosomes per cell, a large number of cells have to be analysed, particularly when the frequency of aberrant cells is low. Automation of dot counting is desirable because manual counting is tedious, fatiguing, an...

Journal: :Genetics 1997
N E Lamb E Feingold S L Sherman

We present analytical methods to estimate the recombinational history of chromosomes in a human population. Our analysis, similar to those utilized in Drosophila, can be used to construct meiotic maps based upon crossover frequencies observed in family data. We apply this method of exchange estimation to a population of paternally and maternally inherited chromosomes 21. The patterns of chromos...

Journal: :Journal of experimental botany 2012
E López M Pradillo C Oliver C Romero N Cuñado J L Santos

Information concerning natural variation either in chiasma frequency or in the genetic basis of any such variation is a valuable tool to characterize phenotypic traits and their genetic control. Here meiotic recombination frequencies are analysed in nine geographically and ecologically diverse accessions of Arabidopsis thaliana, and a comparative study was carried out incorporating previous dat...

2014
Naser M. Salameh

Okra Abelmoschus esculentus L. (Moench), is an economically important vegetable crop grown in tropical and sub-tropical as well as Mediterranean countries. The genome size of the Abelmoschus genus species is still rare. Ploidy determinations have traditionally been done by counting chromosomes of stained root tips, but this method is laborious and often difficult with species which have small c...

Journal: :Current Biology 2016
Tyler S. Machovina Rana Mainpal Anahita Daryabeigi Olivia McGovern Dimitra Paouneskou Sara Labella Monique Zetka Verena Jantsch Judith L. Yanowitz

Crossover (CO) recombination creates a physical connection between homologs that promotes their proper segregation at meiosis I (MI). Failure to realize an obligate CO causes homologs to attach independently to the MI spindle and separate randomly, leading to nondisjunction. However, mechanisms that determine whether homolog pairs have received crossovers remain mysterious. Here we describe a s...

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