Reduced meiotic fitness in hybrids with heterozygosity for heterochromatin in the speciatingMus terricolor complex

Sharma, T.; Bardhan, Amit; Bahadur, Min

doi:10.1007/bf02706218

Cited by 11 publications

(12 citation statements)

References 38 publications

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“…Some rodent species show high hybridism levels, leading to an F1 heterozygous for Robertsonian translocations. The negative effects on the fertility among them are variable but not necessarily high [58, 59]. The nests of C .…”

Section: Discussionmentioning

confidence: 99%

Cytogenetic studies on populations of Camponotus rufipes (Fabricius, 1775) and Camponotus renggeri Emery, 1894 (Formicidae: Formicinae)

et al. 2017

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Two valid ant species, Camponotus rufipes and Camponotus renggeri, have recently been the subject of a broad discussion with reference to taxa synonymization. Both species are quite common among the Neotropical myrmecofauna and share some unique traits, such as the shape of the scape and the pilosity patterns of the tibiae and scapes. A single morphological trait can help distinguish these species; however, only a combination of different approaches can enlighten our view of the complex phylogenetic relationships prevailing in the different populations of these two taxa. Therefore, focusing on the taxonomic issues concerning these two species, a cytogenetic survey including 10 populations of C. rufipes and two populations of C. renggeri was performed. In order to better understand the extent of the relationship between C. rufipes and C. renggeri, two common Neotropical Camponotus species, C. atriceps and C. cingulatus were taken as outgroups. All four species of Camponotus that were studied had 2n = 40 chromosomes (4sm+34st+2t); however, the abundance of chromosome rearrangements observed, combined with several chromosome markers, suggest that C. rufipes and C. renggeri are two good distinct species although closely related. The already reported chromosome translocation 2n = 39 (1m+4sm+32st+2t) for C. rufipes has been found in different populations as in the unprecedented chromosome inversions found both in C. rufipes and in C. renggeri populations. Within the C. renggeri chromosome inversions, both the heterozygous state 2n = 40 (1m+3sm+34st+2t) and the homozygous state, 2n = 40 (2m+2sm+34st+2t) were identified. However, only heterozygous specimens for chromosome inversions were found among C. rufipes, with karyotype configurations distinct from those found in C. renggeri, with 2n = 40 (1m+4sm+34st+2t). None of the populations studied showed signs of mosaic individuals. With respect to rDNA clusters, the 18S rDNA seemed to be more restricted inside the genome, as C. renggeri showed four 18S rDNA clusters, whereas, C. rufipes, C. atriceps, and C. cingulatus showed only two clusters. The chromosome locations of the 5S rDNA clusters were pointed for the first time in Formicidae, and showed itself to be more widely spread over the genome. By combining different chromosome banding approaches it was possible to demonstrate the crucial importance that chromosome inversions played on the karyotype evolution within these ants. The results also showed that chromosome translocations might be a consequence of the chromatin dynamic condition observed among Camponotus species. The homozygosis condition found in a C. renggeri from a Brazilian savanna population for chromosome inversions and the contrasting heterozygous condition for a different kind of chromosome inversion in C. rufipes from the Brazilian coastal rainforest, opens the window for a chromosome race hypothesis within the group C. renggeri and C. rufipes. The wide distribution, rich ecological interactions, genetic diversity, and morphological variability among C....

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Section: Discussionmentioning

confidence: 99%

Cytogenetic studies on populations of Camponotus rufipes (Fabricius, 1775) and Camponotus renggeri Emery, 1894 (Formicidae: Formicinae)

et al. 2017

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“…John (1988) indicates that heterochromatic blocks inhibit chiasmata formation, even though this does not hold for Allium (Loidl, 1982). In the species complex Mus terricolor, Sharma et al (2003) observed variation in the heterochromatin in the short arms of autosomes, which would prevent synaptic association during meiosis. These authors describe this phenomenon as dosedependent and as a potentially critical factor for anomalies, which would be relevant in speciation processes.…”

Section: Discussionmentioning

confidence: 99%

Pleistocene karyotypic divergence in Hoplias malabaricus (Bloch, 1794) (Teleostei: Erythrinidae) populations in southeastern Brazil

2011

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The lacustrine system of the middle rio Doce basin is considered a paradigm of Pleistocene geomorphology. In these lakes, two Hoplias malabaricus karyomorphs (2n = 42A and 2n = 42B) live in sintopy in Carioca Lake. Cytogenetic analyses were performed on 65 specimens from 8 lakes (including Carioca Lake) to determine the distribution and relative frequency of these karyomorphs and the degree of cytogenetic divergence caused putatively by recent geographic isolation. All fish were 2n = 42B karyomorphs, except for 1 specimen from the Marola Lake, which was 2n = 42A. Among-population variation was especially high for C-banding patterns. Other characters such as X chromosome size and CMA 3 /DAPI also varied among populations. Our results suggested that the karyotype of H. malabaricus is able to respond rapidly to geographic isolation, and revealed that heterochromatic variation may represent the lowest hierarchical level of chromosomal evolution.O sistema lacustre da bacia do médio rio Doce é considerado um paradigma da geomorfologia do Pleistoceno. Nestes lagos, dois cariomorfos de Hoplias malabaricus (2n = 42A e 2n = 42B) vivem em sintopia na lagoa Carioca. Análises citogenéticas foram realizadas em 65 amostras de 8 lagos (incluindo lagoa Carioca) para determinar a distribuição e frequência relativa destes cariomorfos e o grau de divergência citogenética aparentemente causada pelo isolamento geográfico recente. Todos os peixes apresentaram o cariomorfo 2n = 42B, com exceção de 1 espécime da lagoa Marola, que foi 2n = 42A. Entre as populações, a variação foi especialmente elevada nos padrões de bandamento C. Outros caracteres como o tamanho do cromossomo X e os padrões de CMA 3 /DAPI também variaram entre as populações. Nossos resultados sugerem que o genoma de H. malabaricus é capaz de responder rapidamente ao isolamento geográfico, revelando que a variação de heterocromatina pode representar o nível hierárquico mais baixo de evolução cromossômica.

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“…Chromatin structure: Chromatin structure has been implicated in chromosome association and progression of meiosis (Peters et al 2001;Sharma et al 2003;Prieto et al 2005;Webster et al 2005). In mice, the lack of the DNA methyltransferase Dmnt3L or the histone methyltransferase Suv39h cause failure of homologous chromosome alignment and synapsis during spermatogenesis (Peters et al 2001;Webster et al 2005).…”

Section: Resultsmentioning

confidence: 99%

Analysis of Close Stable Homolog Juxtaposition During Meiosis in Mutants ofSaccharomyces cerevisiae

Lui¹,

Peoples-Holst²,

et al. 2006

Genetics

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A unique aspect of meiosis is the segregation of homologous chromosomes at the meiosis I division. The pairing of homologous chromosomes is a critical aspect of meiotic prophase I that aids proper disjunction at anaphase I. We have used a site-specific recombination assay in Saccharomyces cerevisiae to examine allelic interaction levels during meiosis in a series of mutants defective in recombination, chromatin structure, or intracellular movement. Red1, a component of the chromosome axis, and Mnd1, a chromosome-binding protein that facilitates interhomolog interaction, are critical for achieving high levels of allelic interaction. Homologous recombination factors (Sae2, Rdh54, Rad54, Rad55, Rad51, Sgs1) aid in varying degrees in promoting allelic interactions, while the Srs2 helicase appears to play no appreciable role. Ris1 (a SWI2/ SNF2 related protein) and Dot1 (a histone methyltransferase) appear to play minor roles. Surprisingly, factors involved in microtubule-mediated intracellular movement (Tub3, Dhc1, and Mlp2) appear to play no appreciable role in homolog juxtaposition, unlike their counterparts in fission yeast. Taken together, these results support the notion that meiotic recombination plays a major role in the high levels of homolog interaction observed during budding yeast meiosis.M EIOSIS is the process by which a parent diploid cell undergoes one round of DNA replication followed by two rounds of chromosome segregation to yield haploid gametes. A unique aspect of meiosis is the segregation of homologous chromosomes at the first meiotic division. Nondisjunction, or improper segregation of homologs, at this stage can lead to gamete aneuploidy, which is a major cause of birth defects in humans (Hassold and Hunt 2001). Homologs are able to correctly orient toward opposite poles of the meiosis I spindle, because a collaboration of DNA crossovers (CR) with sister-chromatid cohesion forms temporary connections between the homologs (Page and Hawley 2003;Petronczki et al. 2003).Homologous chromosomes form progressively stronger associations as cells proceed through meiotic prophase I (Zickler and Kleckner 1999;Storlazzi et al. 2003). In the budding yeast, plants, and mammals, transacting factors required for meiotic recombination are crucial for the pairing and crossing over between homologous chromosomes. In contrast, synaptonemal complex (SC) formation, meiotic nuclear reorganization, and an achiasmate segregation system appear to play supplementary roles in meiotic homolog pairing in the budding yeast (Loidl et al.

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Reduced meiotic fitness in hybrids with heterozygosity for heterochromatin in the speciatingMus terricolor complex

Cited by 11 publications

References 38 publications

Cytogenetic studies on populations of Camponotus rufipes (Fabricius, 1775) and Camponotus renggeri Emery, 1894 (Formicidae: Formicinae)

Cytogenetic studies on populations of Camponotus rufipes (Fabricius, 1775) and Camponotus renggeri Emery, 1894 (Formicidae: Formicinae)

Pleistocene karyotypic divergence in Hoplias malabaricus (Bloch, 1794) (Teleostei: Erythrinidae) populations in southeastern Brazil

Analysis of Close Stable Homolog Juxtaposition During Meiosis in Mutants ofSaccharomyces cerevisiae

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