A model of meiotic chromosome association in tetraploids

Genome ◽  
1989 ◽  
Vol 32 (4) ◽  
pp. 691-707 ◽  
Author(s):  
Charles F. Crane ◽  
David A. Sleper
Keyword(s):  
Meiotic Chromosome ◽  
A Priori ◽  
Meiotic Metaphase ◽  
Chromosome Association ◽  
Preferential Pairing ◽  
Subsequent Formation ◽  
Meiotic Analysis ◽  
Basic Assumptions ◽  
The Relationship ◽  
Metaphase I

A model is constructed for chromosome association at meiotic metaphase I in tetraploids. Probabilities are estimated for each pachytene configuration and for subsequent formation of at least one chiasma in each combination of chromosome arms. Long and short arms can differ but are related through an effective arm ratio so as to maintain the same pattern of genomic affinity for both arms. No other a priori assumptions are made about the pattern of genomic affinity, but the same basic assumptions are made as in our preceding model for triploids. The model is statistically overparameterized and therefore has multiple solutions whose range can be found through repeated optimization from different starting points. In some cases the same expected meiotic analysis can arise from quite different genomic structures, which therefore cannot be distinguished on the basis of unmarked chromosomes. Solutions to the model are conveniently expressed in terms of the proportion of metaphase I association due to each pairwise combination of genomes. Interpretation of model solutions is also aided by the use of numerical indices that reflect closeness to 11 particular genomic structures or that reveal properties of the relationship among variables. The model differs from that of Kimber and Alonso in its handling of two chiasmatically bound arms in a randomly pairing homologous group, and frequently as well in its optimized pattern of genomic affinity upon application to 3:1 and 2:1:1 genomic structures. With the aid of the model, genomic affinity is analyzed in 20 individuals, representing hybrids, amphiploids, and species.Key words: polyploidy, genome analysis, preferential pairing, meiotic model.

A model of meiotic chromosome association in triploids

Genome ◽  
1989 ◽  
Vol 32 (1) ◽  
pp. 82-98 ◽  
Author(s):  
Charles F. Crane ◽  
David A. Sleper
Keyword(s):  
Genome Analysis ◽  
Meiotic Chromosome ◽  
A Priori ◽  
Chiasma Formation ◽  
Chromosome Association ◽  
Subsequent Formation ◽  
Meiotic Analysis ◽  
Partner Exchange ◽  
Translocation Heterozygosity ◽  
Metaphase I

A model was developed for chromosome association at meiotic metaphase I in triploids. Probabilities were estimated for each pachytene configuration and for subsequent formation of at least one chiasma in each combination of chromosome arms. Long and short arms were allowed to differ, but were related through an effective arm ratio so that the pattern of genomic affinity was the same for both arms. No other a priori assumptions were made about the pattern of genomic affinity. However, the usual assumptions of genome analysis were made including the following: identity of genomic-affinity pattern and chiasma frequency across homeologous groups, freedom from translocation heterozygosity, independence of chromosome arms, and absence of chiasma formation on both sides of a synaptic partner exchange within an arm. The model was statistically overparameterized and, therefore, had multiple solutions that yielded the same expected meiotic analysis. The range of these solutions can be found through repeated optimizations from randomly chosen starting values within the permitted ranges of the variables. It was convenient to express the optimized pattern of genomic affinity in terms of the proportions of metaphase I association due to each pairwise combination of genomes. Genomic affinity was analyzed in 16 triploid hybrids with the aid of the model.Key words: polyploidy, genome analysis, meiotic model.

Chromosome organization in meiosis revealed by light microscope analysis of silver-stained cores

Genome ◽  
1987 ◽  
Vol 29 (5) ◽  
pp. 706-712 ◽  
Author(s):  
J. S. Rufas ◽  
J. Gimenez-Abian ◽  
J. A. Suja ◽  
C. Garcia De La Vega
Keyword(s):  
Key Words ◽  
Light Microscope ◽  
Meiotic Chromosome ◽  
Chiasma Formation ◽  
Silver Impregnation ◽  
Meiotic Metaphase ◽  
Chromosome Organization ◽  
Microscope Analysis ◽  
Impregnation Technique ◽  
Metaphase I

Three species of grasshoppers have been analyzed by means of a modified silver impregnation technique that reveals the presence of a chromatid core that identifies chiasmata at first meiotic metaphase. In terms of the behaviour of the chromatid core most of the configurations observed at diplotene with orcein are easily recognized in metaphase I silver-stained bivalents. Some "hidden" configurations, as well as simple chromatin associations, that do not appear to represent chiasmata have also been detected. The disposition and behaviour of the chromatid cores in metaphase I and anaphase I provide grounds to support a reorganization of half-bivalents between first and second division. Key words: chromatid core, meiotic chromosome organization, chiasma formation, insect cytogenetics.

Meiotic chromosome association in diploid and tetraploid Avena strigosa Schrel.

Genome ◽  
1989 ◽  
Vol 32 (6) ◽  
pp. 972-977 ◽  
Author(s):  
S. N. Zadoo ◽  
R. N. Choubey ◽  
S. K. Gupta ◽  
J. Sybenga
Keyword(s):  
High Frequency ◽  
Meiotic Chromosome ◽  
Chromosome Association ◽  
Present Material ◽  
Negative Interference ◽  
Avena Strigosa ◽  
Partner Exchange ◽  
Quadrivalent Frequency ◽  
Chiasma Interference ◽  
Metaphase I

In diploid Avena strigosa the frequency and distribution of open (rod) bivalents suggest that a limited number of chromosomes, possibly two, fail to have a chiasma in one (short) arm in over 60% of the cells. In the tetraploid these are expected to form bivalents instead of quadrivalents at metaphase I of meiosis in a high frequency. In addition, interstitial chiasmata are expected in the long arms of these chromosomes, when involved in quadrivalents. In the tetraploid the frequency of quadrivalents is indeed low, and the configurations with interstitial chiasmata are distributed as expected. However, application of Sybenga's models suggests that the pairing system rather than the chiasma system would be responsible for the low quadrivalent frequency. It is suggested that apparent negative chiasma interference across the point of pairing partner exchange, resulting from variation in its location, invalidates application of these models to the present material. Negative interference results in an even higher than expected open bivalent frequency, in combination with a relatively high ring quadrivalent frequency. In addition, not only the subacrocentric chromosomes but also the more metacentric chromsomes, by this same mechanism, tend to form open bivalents more often than in the diploid.Key words: meiosis, bivalent, quadrivalent, diploid, tetraploid, Avena strigosa

scholarly journals Chromosome differentiation and pairing behavior of polyploids: an assessment on preferential metaphase I associations in colchicine-induced autotetraploid hybrids within the genus Secale.

Genetics ◽  
1991 ◽  
Vol 128 (2) ◽  
pp. 433-442
Author(s):  
E Benavente ◽  
J Orellana
Keyword(s):  
Colchicine Treatment ◽  
Chromosome Association ◽  
Clear Relationship ◽  
Preferential Pairing ◽  
Chromosome Differentiation ◽  
Pairing Behavior ◽  
Parental Lines ◽  
Metaphase I

Abstract Preferential chromosome association at metaphase I has been analyzed and compared in autotetraploid cells obtained by colchicine treatment of hybrid diploid rye plants with different degrees of chromosomal divergence between homologs. The tendency to identical over homologous, but not identical, pairing preferences detected when homologous partners are contributed by less related parental lines indicates that chromosome differentiation may play an important role on preferential pairing behavior of polyploids. However, associations between more similar (identical) partners are not always favored, thus suggesting that additional factors must be considered. Other hypotheses for explaining pairing preferences in competitive situations are discussed. No clear relationship has been found between multivalent frequencies at metaphase I and chromosome differentiation between homologs or preferential pairing behavior. Therefore evolutionary divergences among related genomes should be carefully stated when evaluated from metaphase I configuration frequencies.

Effects of a Priori Liking on the Elicitation of Mimicry

2010 ◽  
Vol 57 (6) ◽  
pp. 412-418 ◽  
Author(s):  
Mariëlle Stel ◽  
Rick B. van Baaren ◽  
Jim Blascovich ◽  
Eric van Dijk ◽  
Cade McCall ◽  
...  
Keyword(s):  
A Priori ◽  
The Relationship

Mimicry and prosocial feelings are generally thought to be positively related. However, the conditions under which mimicry and liking are related largely remain unspecified. We advance this specification by examining the relationship between mimicry and liking more thoroughly. In two experiments, we manipulated an individual’s a priori liking for another and investigated whether it influenced mimicry of that person. Our experiments demonstrate that in the presence of a reason to like a target, automatic mimicry is increased. However, mimicry did not decrease when disliking a target. These studies provide further evidence of a link between mimicry and liking and extend previous research by showing that a certain level of mimicry even occurs when mimicry behavior is inconsistent with one’s goals or motivations.

The Impact of Competitive Quasi-Market on Service Delivery in Benue State University, Makurdi Nigeria

GIS Business ◽  
2019 ◽  
Vol 14 (4) ◽  
pp. 85-98
Author(s):  
Idoko Peter
Keyword(s):  
Service Delivery ◽  
A Priori ◽  
Least Square ◽  
Secondary Source ◽  
State University ◽  
Ordinary Least Square ◽  
Negative Effect ◽  
The Impact ◽  
The Relationship

This research the impact of competitive quasi market on service delivery in Benue State University, Makurdi Nigeria. Both primary and secondary source of data and information were used for the study and questionnaire was used to extract information from the purposively selected respondents. The population for this study is one hundred and seventy three (173) administrative staff of Benue State University selected at random. The statistical tools employed was the classical ordinary least square (OLS) and the probability value of the estimates was used to tests hypotheses of the study. The result of the study indicates that a positive relationship exist between Competitive quasi marketing in Benue State University, Makurdi Nigeria (CQM) and Transparency in the service delivery (TRSP) and the relationship is statistically significant (p<0.05). Competitive quasi marketing (CQM) has a negative effect on Observe Competence in Benue State University, Makurdi Nigeria (OBCP) and the relationship is not statistically significant (p>0.05). Competitive quasi marketing (CQM) has a positive effect on Innovation in Benue State University, Makurdi Nigeria (INVO) and the relationship is statistically significant (p<0.05) and in line with a priori expectation. This means that a unit increases in Competitive quasi marketing (CQM) will result to a corresponding increase in innovation in Benue State University, Makurdi Nigeria (INVO) by a margin of 22.5%. It was concluded that government monopoly in the provision of certain types of services has greatly affected the quality of service experience in the institution. It was recommended among others that the stakeholders in the market has to be transparent so that the system will be productive to serve the society effectively

Educación y valores

2014 ◽  
pp. 83
Author(s):  
Sabino de Juan López
Keyword(s):  
Key Words ◽  
A Priori ◽  
Palabras Clave ◽  
The Subject ◽  
The Relationship ◽  
Problem Of The Criterion

RESUMEN En el artículo se ofrece una reflexión en torno a la educación y valores. Tras una referencia a los diferentes sentidos en que se puede plantear el problema en función de la forma como se puede entender la relación entre los dos sustantivos “educación” y “valores”, la reflexión se centra en algunos problemas relacionados con los valores en cuanto contenidos de la educación. Primeramente se refiere al problema del criterio en función del cual determinar los valores de la educación, concluyendo en que el criterio no podía ser ni de carácter a priori, ni empírico, sino “sintético”. A continuación, se afronta el problema del principio, de la fuente de los valores, o la concreción del criterio de los valores de la educación, entendiendo que éstos deberían ser determinados a partir del sujeto de la educación. Se concluye con la referencia a una exigencia de los valores de la educación, la configuración de una totalidad unitaria e interactiva. Palabras clave: educación, valores, fuente de valores, integración, cultura EDUCATION AND VALUES ABSTRACT The article offers a reflection on education and values. After a reference to the different senses in which one can pose the problem in terms of how you can understand the relationship between the two nouns “education” and “values”, reflection focuses on some problems related to the values in the contents of education. First, it concerns the problem of the criterion against which to determine the values of education, concluding that the criterion could be neither a priori in nature, not empirical, but “synthetic”. Herein, the problem of principle is faced, the source of values, or the realization of the criterion of the values of education, understanding that these should be determined from the subject of education. It concludes with the reference of a requirement of the values in education, setting up a unitary and interactive whole. Key Words: education, values , power values , integration, culture

scholarly journals The crowd and citylife: Materiality, negotiation and inclusivity at Tokyo’s train stations

Urban Studies ◽  
2021 ◽  
pp. 004209802110078
Author(s):  
Romit Chowdhury ◽  
Colin McFarlane
Keyword(s):  
A Priori ◽  
Urban Density ◽  
History Of ◽  
Mode Of Being ◽  
The Relationship ◽  
The City ◽  
Human Embodiment

In the history of urban thought, density has been closely indexed to the idea of citylife. Drawing on commuters’ experiences and perceptions of crowds in and around Tokyo’s Shinjuku Station, this article offers an ethnographic perspective on the relationship between urban crowds and life in the city. We advance understandings of the relations between the crowd and citylife through three categories of ‘crowd relations’– materiality, negotiation and inclusivity – to argue that the multiplicity of meanings which accrue to people’s encounters with crowds refuses any a priori definitions of optimum levels of urban density. Rather, the crowd relations gathered here are evocations of citylife that take us beyond the tendency to represent the crowd as a particular kind of problem, be it alienation, exhaustion or a threshold for ‘good’ and ‘bad’ densities. The portraits of commuter crowds presented capture the various entanglements between human and non-human, embodiment and mobility, and multiculture and the civic, through which citylife emerges as a mode of being with oneself and others.

Support for the Americans With Disabilities Act Among Nondisabled People

2021 ◽  
pp. 104420732110231
Author(s):  
Carli Friedman ◽  
Laura VanPuymbrouck
Keyword(s):  
Civil Rights ◽  
Americans With Disabilities Act ◽  
A Priori ◽  
People With Disabilities ◽  
Secondary Data ◽  
The United States ◽  
Limited Participation ◽  
Persons With Disabilities ◽  
Research Questions ◽  
The Relationship

The Americans with Disabilities Act (ADA) opened the doors to access and enhanced the civil rights of people with disabilities. However, a lack of accessibility to all segments of society continues throughout the United States and is frequently described by people with disabilities as a leading cause for limited participation. Beliefs and attitudes regarding disability can affect critical decisions regarding inclusion and people with disabilities’ civil rights. Therefore, the purpose of this study was to explore support and opposition to the ADA among nondisabled people. We had the following research questions: (a) What is the relationship between disability prejudice and support for the ADA? and (b) When controlling for disability prejudice, what other factors lead people to support the ADA? To do so, we examined secondary data from approximately 13,000 participants from all 50 states and the District of Columbia. Findings from this study revealed that people who oppose the ADA are significantly more prejudiced toward people with disabilities than people who support the ADA. Understanding and becoming aware of attitudes and prejudice toward persons with disabilities can be a first step toward dispelling such beliefs and possibly a priori step to achieving the intent and spirit of the ADA.

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