What makes homologous chromosomes find each other in meiosis? A review and an hypothesis

Sybenga, J.

doi:10.1007/s004120050371

Cited by 57 publications

(43 citation statements)

References 88 publications

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“…Chiasmata and crossing over are generally located in specific segments of chromosomes, and the standard is genetically controlled (Sybenga 1999). In maize (Zea mays L.), the frequency of chiasmata is under polygenic control, which may lead to genetic variability in lineages (Pagliarini 1980).…”

Section: Discussionmentioning

confidence: 99%

Meiotic behavior in wild and domesticated species of Passiflora

Souza¹,

Pereira²

2011

Rev. bras. Bot.

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-(Meiotic behavior in wild and domesticated species of Passiflora). The meiotic behavior of fourteen Passiflora taxa was analyzed. The species were grouped according to the n value (6, 9 and 12) for statistical studies. Some species presented tetravalent associations or univalent chromosomes in diakinesis, bivalent formation prevailing. The qui-square test revealed significant differences in the chiasma frequency among species for n = 9 and n = 6 groups. There was predominance of interstitial chiasmata in almost all studied species. The n = 12 group was the only one whose meiotic behavior was considered similar due to the quantity of chiasmata per cell, tendency of interstitial chiasma localization. Some species presented meiotic irregularities, such as laggard and precocious chromosomes in meiosis I. In telophase II the percentages of meiotic irregularities was low. Irregularities in the spindle orientation were presented in higher percentages in the end of meiosis II, and were also responsible for post-meiotic abnormal products. The irregularities observed during meiosis can have influence on the percentage of sterile pollen grains and success of interspecific crossings in Passiflora species.Key words -chiasmata, meiotic index, microsporogenesis, passion flower, post-meiotic products RESUMO -(Comportamento meiótico em espécies silvestres e domesticadas de Passiflora). O comportamento meiótico de 14 táxons foi analisado. As espécies foram agrupadas de acordo com o valor de n (6, 9 e 12) para estudos estatísticos. Algumas espécies apresentaram associações tetravalentes ou cromossomos univalentes em diacinese, prevalecendo formação de bivalentes. O teste de qui-quadrado revelou diferenças significativas na freqüência de quiasmas entre espécies para grupos com n = 9 e n = 6. Houve predominância de quiasmas intersticiais em quase todas as espécies estudadas. O grupo com n = 12 foi o único cujo comportamento meiótico foi considerado similar devido à quantidade de quiasmas por célula, tendência à localização intersticial de quiasmas. Algumas espécies apresentaram irregularidades meióticas, tais como cromossomos retardatários ou precoces em meiose I. Na telófase II os percentuais de irregularidades meióticas foram baixos. Irregularidades na orientação das fibras dos fusos ocorreram em alto percentual no final da meiose II, sendo também responsáveis por produtos pós-meióticos anormais. As irregularidades observadas durante a meiose podem ter influência sobre o percentual de grãos de pólen estéreis e o sucesso de cruzamentos interespecíficos em espécies de Passiflora.Palavras-chave -índice meiótico, microsporogênese, produtos pós-meióticos, quiasmas

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Section: Discussionmentioning

confidence: 99%

Meiotic behavior in wild and domesticated species of Passiflora

Souza¹,

Pereira²

2011

Rev. bras. Bot.

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“…Minisatellites at imprinted loci are thought to play a role in the imprint control (Chaillet et al 1995;Neumann et al 1995). More speculatively, minisatellites have been proposed as intermediates in chromosome pairing initiation in some eukaryote genomes (Ashley 1994;Sybenga 1999), which might be related to their proposed recombinogenic properties (Boan et al 1998;Wahls and Moore 1998). (3) Finally, minisatellites may constitute chromosome fragile sites (for review, see Sutherland et al 1998) and have been found in the vicinity of a number of recurrent translocation breakpoints and in the switch recombination site in immunoglobulin heavy chain genes (Brusco et al 1999).…”

Section: Classic Definition and Early Applications Of Minisatellitesmentioning

confidence: 99%

“…Subtelomeric minisatellites are one class of sequences that have been put forward as candidates to help explain this paradox (Ashley 1994;Sybenga 1999). Specific mechanisms would be activated in male meiosis, and minisatellites would be involved in chromosome pairing, either directly or via interactions with pairing proteins.…”

Section: Genome Research 903mentioning

confidence: 99%

Minisatellites: Mutability and Genome Architecture

2000

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Minisatellites have been found in association with important features of human genome biology such as gene regulation, chromosomal fragile sites, and imprinting. Our knowledge of minisatellite biology has greatly increased in the past 10 years owing to the identification and careful analysis of human hypermutable minisatellites, experimental models in yeast, and recent in vitro studies of minisatellite recombination properties. In parallel, minisatellites have been put forward as potential biomarkers for the monitoring of genotoxic agents such as ionizing radiation. We summarize and discuss recent observations on minisatellites. In addition we take advantage of recent whole chromosome sequence data releases to provide a unifying view which may facilitate the annotation of tandem repeat sequences.

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“…There are several recent papers on this subject, both from a cytogenetic and a mathematical modelling point of view (Sybenga, 1994(Sybenga, , 1995(Sybenga, , 1996(Sybenga, , 1999Jackson and Jackson, 1996). The evidence suggests that these situations should be characterised by a general polyploid inheritance model with no complete preference to homologous or homeologous paring (Wu et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Estimation of allele frequencies in polyploids under certain patterns of inheritance

et al. 2005

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Allele frequencies have long been studied by biologists interested in evolution and speciation. More recently, with the application of molecular markers in human DNA profiling we have also seen the need for reliable population allele frequency estimates for making probabilistic inferences. There is now interest in applying the same DNA profiling technology to identification of plant varieties. HortResearch maintains a large germplasm of horticultural plant species. It is becoming evident that accurate identification of these accessions through DNA fingerprinting is essential for effective utilisation and maintenance of this germplasm. Microsatellites are the markers of choice for this fingerprinting. However, such markers do not reveal the dosage of alleles in a polyploid. Polyploidy is common amongst horticultural plants. Estimating allele frequencies in a polyploid population is, therefore, complicated because of some marker genotypes being phenotypically indistinguishable. For example, in a tetraploid, with four alleles at a locus showing polysomic inheritance, although 35 genotypes are possible, these will fall into only 15 marker phenotypic classes. Furthermore 'null' individuals are rarely detected in polyploids. Furthermore, some polyploids can be cryptic exhibiting disomy, instead of the polysomic inheritance. We will discuss the implications of these factors and present an EM-type algorithm for estimating allele frequencies of a polyploid population under certain patterns of inheritance. The method will be demonstrated on simulated data. We also discuss the nature of some of the additional problems that may be encountered with estimating allele frequencies in polyploids for which other solutions still need to be developed. Heredity (2005) 95, 327-334.

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What makes homologous chromosomes find each other in meiosis? A review and an hypothesis

Cited by 57 publications

References 88 publications

Meiotic behavior in wild and domesticated species of Passiflora

Meiotic behavior in wild and domesticated species of Passiflora

Minisatellites: Mutability and Genome Architecture

Estimation of allele frequencies in polyploids under certain patterns of inheritance

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