共查询到20条相似文献,搜索用时 15 毫秒
1.
Paolo Franchini Paolo Colangelo Emanuela Solano Ernesto Capanna Erik Verheyen Riccardo Castiglia 《Evolution; international journal of organic evolution》2010,64(7):2020-2032
The West European house mouse, Mus musculus domesticus, is a particularly suitable model to investigate the role of chromosomal rearrangements in reproductive isolation. In fact, it exhibits a broad range of chromosomal polymorphism due to Robertsonian (Rb) fusions leading to various types of contact zones between different chromosomal races. In the present study, we analyzed a parapatric contact in central Italy between the Cittaducale chromosomal race (CD: 2n= 22) and the surrounding populations with standard karyotype (2n= 40) to understand if Rb fusions play a causative role in speciation. One hundred forty‐seven mice from 17 localities were genotyped by means of 12 microsatellite loci. A telomeric and a pericentromeric locus situated on six chromosome arms (four Rbs and one telocentric) were selected to detect differences in the amount of gene flow for each locus in different chromosomal positions. The analyses performed on the two subsets of loci show differences in the level of gene flow, which is more restricted near the centromeres of Rb chromosomes. This effect is less pronounced in the homozygotes populations settled at the border of the hybrid zone. We discuss the possible cause of the differential porosity of gene flow in Rbs considering “hybrid dysfunctions” and “suppressed recombination” models. 相似文献
2.
MILENA BARCELOS CARDOSO MARIA TERESA SCHIFINO-WITTMANN MARIA HELENA BODANESE-ZANETTINI 《Botanical journal of the Linnean Society. Linnean Society of London》2000,134(4):549-556
Chromosome numbers were determined in 52 individuals of 14 taxa of Leucaena Benth. from 22 populations. For L. cuspidata and L. kmpirana these are the first published chromosome counts. Intraspecific variability was found for L. lempirana, L. macrophjlta and L. shanonii , and one diploid population of the tetraploid species L. pallida was identified. Comparison of our data with those in the literature showed that for L. collinsii and L. macrophylla there is a relationship between chromosome number and subspecies delimitation. The variability detected in chromosome numbers shows the complexity of the diploid and tetraploid species evolution, and suggests multiple origins for some of the polyploid taxa. 相似文献
3.
罗伯逊易位研究的进展 总被引:2,自引:0,他引:2
本文总结了罗伯逊易位研究的现状、内容和技术方法,并对它在畜牧品种的改良、分子遗传学方面的应用作了探讨,指出了它在研究进化生物学方面的重要意义。Abstract:Robertsonian translocation is important in the study of evolution biology.Current progress,contents,technology and methods about Robertsonian translocation studies are introduced in the article.The usefulness in improving the breeds of pasturages and molecular genetic aspect are also discussed. 相似文献
4.
JAROSLAV PIáLEK HEIDI C. HAUFFE JEREMY B. SEARLE 《Biological journal of the Linnean Society. Linnean Society of London》2005,84(3):535-563
Although the standard karyotype of the western house mouse, Mus musculus domesticus , consists entirely of acrocentric chromosomes, there are 97 distinct 'populations' that are characterized by various combinations of metacentric chromosomes that have arisen by Robertsonian (Rb) fusions and whole-arm reciprocal translocations (WARTs). In this review we discuss the processes behind the origin and fixation of these rearrangements and then present a unified list of all known metacentric populations and evaluate their phylogenetic relationships. Eleven independent phylogeographical 'systems', each consisting of 2–25 metacentric populations, were identified in Scotland, Denmark, Northern Europe–Northern Switzerland, Southern Switzerland, Northern Italy, Croatia, Spain, Central–Southern Italy, Peloponnesus, Mainland Greece and Madeira. There are six isolated metacentric populations that do not belong to any of these systems. To generate phylogenies of the metacentric populations within each system, we determined those outcomes with the fewest steps regarding accumulation of metacentrics by Rb fusions, WARTs and zonal raciation and taking into account geographical proximity. These phylogenies should be viewed as working hypotheses that will be refined with further chromosomal and molecular data and improvements in methods of phylogenetic reconstruction. The list of metacentric populations and our phylogenies are also published electronically and can be accessed at http://www.studenec.ivb.cz/Projects/RobertsonianMice/ . © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 84 , 535–563. 相似文献
5.
GEORGE P. MITSAINAS EVA B. GIAGIA-ATHANASOPOULOU 《Biological journal of the Linnean Society. Linnean Society of London》2005,84(3):503-513
The karyotype of the house mouse, Mus musculus domesticus , was examined in 282 specimens from 44 localities, in an effort to gain better understanding of the Robertsonian (Rb) variation known to exist in Greece. We consider that an Rb system exists in Peloponnisos, southern Greece, distributed in an area that is substantially larger than previously known. It consists of at least three Rb races with 2 n = 30, 2 n = 24 and 2 n = 28, respectively, the last being reported for the first time in this paper and carrying Rb(3.6), Rb(8.12), Rb(10.14), Rb(13.15), Rb(9.16) and Rb(11.17) in a homozygous state. Additional instances of variation in this Rb system include individuals with 2 n = 31 and 32 of variable Rb constitution and hybrids between the Rb races with 2 n = 30 and 2 n = 24. In southern Peloponnisos, Rb(10.14) was found in either a homozygous or a heterozygous state (2 n = 38 or 39). The relationships among the Rb populations of Peloponnisos are discussed and hypotheses for their evolution are proposed. Rb variation was also recorded in two new locations of eastern Sterea Ellas (2 n = 28 and 29) and one in Ipiros, north-west Greece (2 n = 38). These findings corroborate the existence of two separate Rb systems in those two areas. Moreover, among a number of islands surveyed, Rb variation was only found in Kythira island, with Rb(10.14) in a heterozygous state (2 n = 39). Finally, the typical all-acrocentric karyotype (2 n = 40) was found in 51 of the animals studied from 13 localities. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 84 , 503–513. 相似文献
6.
Thomas Wicker Rod A. Wing Ingo Schubert 《The Plant journal : for cell and molecular biology》2015,84(4):747-759
All grass species evolved from an ancestor that underwent a whole‐genome duplication (WGD) approximately 70 million years ago. Interestingly, the short arms of rice chromosomes 11 and 12 (and independently their homologs in sorghum) were found to be much more similar to each other than other homeologous regions within the duplicated genome. Based on detailed analysis of rice chromosomes 11 and 12 and their homologs in seven grass species, we propose a mechanism that explains the apparently ‘younger’ age of the duplication in this region of the genome, assuming a small number of reciprocal translocations at the chromosome termini. In each case the translocations were followed by unbalanced transmission and subsequent lineage sorting of the involved chromosomes to offspring. Molecular dating of these translocation events also allowed us to date major chromosome ‘fusions’ in the evolutionary lineages that led to Brachypodium and Triticeae. Furthermore, we provide evidence that rice is exceptional regarding the evolution of chromosomes 11 and 12, inasmuch as in other species the process of sequence exchange between homeologous chromosomes ceased much earlier than in rice. We presume that random events rather than selective forces are responsible for the observed high similarity between the short arm ends of rice chromosomes 11 and 12. 相似文献
7.
The evolution of the Robertsonian (Rb) system of the house mouse (Mus musculus domesticus) located in Peloponnisos (Greece) is examined, under the possibility of whole arm reciprocal translocation (WART) involvement
in the formation process of two of its Rb races with 2n = 24 and 2n = 28, respectively, characterized by monobrachial homology. Our contribution reinforces the opinion that WARTs may have been
more actively involved in the formation of Rb races in this subspecies than previously thought. Moreover, the consideration
of WARTs, when studying complex Rb systems permits the suggestion of more sensible and parsimonial pathways for their phylogenetic
history than when WARTs are excluded. 相似文献
8.
9.
Meiotic segregation patterns of carriers of Robertsonian translocations (RT) are important for assessing the risk of unbalanced forms. We investigated the ratio of sperm with t(21;21) to sperm with nullisomy for chromosome 21; the segregation of the t(21;21) along with sex chromosomes, and also interchromosomal effects on chromosome 10 by using three color fluorescence in situ hybridization (FISH) with telomere specific (Tel 21q) and centromere-specific alpha satellite probes for chromosomes X, Y, and 10. The percentage of cosegregation of t(21;21) with sex chromosomes (49.50%) and without sex chromosomes (46.98%) was not significant. There are no significant differences between the percentages of cosegregation of t(21;21) with chromosome X (23.36%) and with chromosome Y (26.16%). No evidence of an interchromosomal effect on chromosome 10 was detected, the percentage of chromosome 10 aneuploidy being similar to that in controls. In addition, the frequency of diploid sperm nuclei was not significantly higher in the carrier (0.32%) than in the controls (0.44%) (P > 0.05). The sex ratio was similar within the carrier and the controls and between the carrier and the control. Three color-FISH analysis, using different probe combinations, seems a rapid and accurate tool for direct analysis of meiotic segregation product. 相似文献
10.
Michèle Lemonnier-Darcemont Anne-Marie Dutrillaux Bernard Dutrillaux Christian Darcemont 《法国昆虫学会纪事》2013,49(3-4):357-360
Dans le cadre de ses recherches sur le genre Saga, le G.E.E.M. enregistre en mai 2009 la naissance en élevage, d’un male et d’une femelle issus du croisement d’une femelle de Saga campbelli Kaltenbach 1965 avec un mâle de Saga hellenica Kaltenbach 1967. L’analyse cytogénétique de la femelle hybride confirme son origine hybride et qu’une seule translocation robertsonienne sépare les caryotypes de S. hellenica de S. campbelli. L’habitus du mâle montre une affinité plus forte avec S. hellenica qu’avec S. campbelli. 相似文献
11.
The meiotic behavior of Robertsonian heterozygotes of Dichroplus pratensis was analyzed in order to establish the nature of the fusion polymorphisms (stable or transient) that occur in the species. The range of fusion frequencies varies widely for each fusion studied and populations with extreme frequencies exist, which could indicate a tendency for the loss or fixation of a given rearrangement. Our results revealed that no significant correlation exists between orientation (convergent and non-convergent) in PMI and MI and fusion frequency, nor between aneuploidy and fusion frequency. Thus, orientation and segregation seem to be independent of the frequencies of the fusions, which also do not appear to affect severely the fertility of heterozygotes. Our data suggest that the polymorphisms are, at least, cytogenetically stable.Both authors are affiliated to the CONICET (Argentina) 相似文献
12.
13.
Eleonora Cappelletti Francesca M Piras Lorenzo Sola Marco Santagostino Wasma A Abdelgadir Elena Raimondi Francesco Lescai Solomon G Nergadze Elena Giulotto 《Molecular biology and evolution》2022,39(8)
Centromeres are epigenetically specified by the histone H3 variant CENP-A and typically associated with highly repetitive satellite DNA. We previously discovered natural satellite-free neocentromeres in Equus caballus and Equus asinus. Here, through ChIP-seq with an anti-CENP-A antibody, we found an extraordinarily high number of centromeres lacking satellite DNA in the zebras Equus burchelli (15 of 22) and Equus grevyi (13 of 23), demonstrating that the absence of satellite DNA at the majority of centromeres is compatible with genome stability and species survival and challenging the role of satellite DNA in centromere function. Nine satellite-free centromeres are shared between the two species in agreement with their recent separation. We assembled all centromeric regions and improved the reference genome of E. burchelli. Sequence analysis of the CENP-A binding domains revealed that they are LINE-1 and AT-rich with four of them showing DNA amplification. In the two zebras, satellite-free centromeres emerged from centromere repositioning or following Robertsonian fusion. In five chromosomes, the centromeric function arose near the fusion points, which are located within regions marked by traces of ancestral pericentromeric sequences. Therefore, besides centromere repositioning, Robertsonian fusions are an important source of satellite-free centromeres during evolution. Finally, in one case, a satellite-free centromere was seeded on an inversion breakpoint. At 11 chromosomes, whose primary constrictions seemed to be associated with satellite repeats by cytogenetic analysis, satellite-free neocentromeres were instead located near the ancestral inactivated satellite-based centromeres; therefore, the centromeric function has shifted away from a satellite repeat containing locus to a satellite-free new position. 相似文献
14.
15.
S. Herzog R. Harrington 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1991,82(4):425-429
Summary The karyotypes of 46 animals from a population ofCervus elaphus, Cervus nippon, and hybridsCervus elaphus xCervus nippon were studied using G- and C-banding techniques. It was found that four chromosome pairs known from the karyotype ofCervus elaphus are involved in two systems of Robertsonian translocations. Pedigree analysis supports the hypothesis of a simple Mendelian inheritance of each translocation system. With respect to these translocation systems, the population shows no significant deviation from the corresponding Hardy-Weinberg-structure. Thus, hybridization events can be accepted as a major factor in karyotype evolution of deer. 相似文献
16.
Kathryn A. Coates 《Hydrobiologia》1989,180(1):35-45
The identification of gut diverticula at 7/8 as a synapomorphy and recognition of all taxa of Guaranidrilus has been obscured by losses of gut diverticula within the lineage. The homoplastic occurrence of basally unpaired peptonephridia in some enchytraeid species has similarly obscured the limits of Hemienchytraeus. Taxa with unpredictable relationships, morphogenic irregularities in some reproductive structures, and, apparently, modified modes of reproduction, suggest the possibilities of hybridization between taxa with both close and distant relationships. 相似文献
17.
Immigration into small isolated captive and wild populations is recommended to alleviate inbreeding depression. The effects on reproductive fitness of introducing one immigrant into 10 small partially inbred captive populations of D. melanogaster were evaluated. The relative reproductive fitness of the immigrant populations (0.628) was approximately double that of the isolated populations (0.294) and about halfway between the isolated populations and the outbred base population (1.00). Every replicate population increased in fitness following the introduction of an immigrant. The improvements in reproductive fitness shown by the immigrant populations were not due to F1 hybrid vigor, as the experimental populations underwent three generations of random mating prior to the fitness tests. These results indicate substantial benefits can be gained by the translocation of as few as a single animal between small, partially inbred populations. © 1992 Wiley-Liss, Inc. 相似文献
18.
麻雀核型研究的新发现 总被引:7,自引:4,他引:3
本文对分布于牡丹江地区的麻雀(Passer montanus montanus Linnaeus)(指名亚种)进行了核型、C带和G带研究,发现了麻雀同一亚种内具有4种核型,即2n=78(正常)、2n=77、2n=76和2n=78(异常)。经分析比较认为,4种核型中,2n=78(正常)为基础核型,而其他3种核型是在此基础上由微小染色体发生过罗伯逊易位(Robertsonian translocation)形成的。从而为罗伯逊易位在鸟类核型进化中起重要作用这一推测提供了直接的证据。Abstract: The karyotype .C-band and G-band of the tree sparrow (Passer montanus montanus L.) in Mudanjiang area were studied, and 4 karyotypes were discovered, they are 2n=78 (normal), 2n=77,2n=76 and 2n=78(unusual). By analysis and comparison it can be considered that the 2n=78(normal) is a basic karyotype in the 4 karyotypes, and the others are formed by Robertsonina translocation between microchromosomes on this base, thus providing the inference that the Robertsonian translocation plays an important role in karyotype evolution of birds with direct evidence. 相似文献
19.
Ching‐Ho Chang Amanda M. Larracuente 《Evolution; international journal of organic evolution》2017,71(5):1285-1296
Robertsonian translocations resulting in fusions between sex chromosomes and autosomes shape karyotype evolution by creating new sex chromosomes from autosomes. These translocations can also reverse sex chromosomes back into autosomes, which is especially intriguing given the dramatic differences between autosomes and sex chromosomes. To study the genomic events following a Y chromosome reversal, we investigated an autosome‐Y translocation in Drosophila pseudoobscura. The ancestral Y chromosome fused to a small autosome (the dot chromosome) approximately 10–15 Mya. We used single molecule real‐time sequencing reads to assemble the D. pseudoobscura dot chromosome, including this Y‐to‐dot translocation. We find that the intervening sequence between the ancestral Y and the rest of the dot chromosome is only ~78 Kb and is not repeat‐dense, suggesting that the centromere now falls outside, rather than between, the fused chromosomes. The Y‐to‐dot region is 100 times smaller than the D. melanogaster Y chromosome, owing to changes in repeat landscape. However, we do not find a consistent reduction in intron sizes across the Y‐to‐dot region. Instead, deletions in intergenic regions and possibly a small ancestral Y chromosome size may explain the compact size of the Y‐to‐dot translocation. 相似文献
20.
Metaphase I orientation of centric fusion trivalents was studied in 24 single, 19 double and 3 triple heterozygotes of Dichroplus pratensis. Different populations of this South American melanopline grasshopper are polymorphic for seven Robertsonian fusions, and the polymorphisms seem to be stable. Several cytogenetic factors involved in the orientation and segregation of the meiotic configurations such as chromosomal length, symmetry and number and position of chiasmata, have been analysed in previous works. In this paper we study another factor that is relevant in the above respect in individuals with more than one heterozygous fusion: interaction among configurations regarding orientation.Our results indicate that, when there are two or three trivalents present in the MI cell, there is an interaction in such a way that the number of metaphases in which the two or three trivalents are non-disjunctionally oriented is always significantly higher than expected under a hypothesis of independence. However, the number of cells in which all trivalents are disjunctionally oriented does not decrease significantly, so an increase of unbalanced gametes due to this factor is not expected. The stability of the polymorphisms would thus not be affected.Both authors are affiliated with the CONICET (Argentina) 相似文献