The pattern of polytene chromosome synapsis in Drosophila species and interspecific hybrids

Chromosoma ◽  
1976 ◽  
Vol 57 (3) ◽  
pp. 285-295 ◽  
Author(s):  
M. B. Evgen'ev ◽  
G. G. Polianskaya
Keyword(s):  
Polytene Chromosome ◽  
Interspecific Hybrids ◽  
Drosophila Species ◽  
Chromosome Synapsis

Metaphase karyotype identity in four homosequential Drosophila species from Hawaii

1985 ◽  
Vol 27 (3) ◽  
pp. 308-311 ◽  
Author(s):  
Linda S. Chang ◽  
Hampton L. Carson
Keyword(s):  
Polytene Chromosome ◽  
Chromosomal Rearrangements ◽  
The Other ◽  
Drosophila Species ◽  
Mitotic Metaphase ◽  
Metaphase Chromosomes ◽  
Hawaiian Drosophila ◽  
Gross Chromosomal Rearrangements ◽  
Rule Out

Four recently evolved species of Hawaiian Drosophila (silvestris, heteroneura, dijferens, and planitibia) have previously been shown to be homosequential in all five polytene chromosome arms. This suggests that the changes involved in speciation are at the genic level and hence are not evident in the polytene banding sequences. Because this does not rule out the occurrence of heterochromatic differences between these homosequential species, the present study was carried out to examine this possibility. These species are now shown to have identical heterochromatin distributions in mitotic metaphase chromosomes. This proves that neither gross chromosomal rearrangements nor novel heterochromatic blocks have been involved in the divergence of these four species. A fifth, and evolutionarily more distant, species (hemipeza) belonging to the same subgroup has a significantly different heterochromatin distribution from the other four species.Key words: heterochromatin, metaphase karyotypes, Hawaiian Drosophila.

MEIOTIC SEGREGATION AND MALE RECOMBINATION IN INTERSPECIFIC HYBRIDS OF DROSOPHILA

Genetics ◽  
1986 ◽  
Vol 114 (2) ◽  
pp. 485-494
Author(s):  
Jerry A Coyne
Keyword(s):  
Interspecific Hybrids ◽  
Meiotic Drive ◽  
Drosophila Species ◽  
Meiotic Segregation ◽  
Mendelian Segregation ◽  
Male Recombination ◽  
Genetic Elements ◽  
Transposable Genetic Elements

ABSTRACT Male hybrids between three pairs of Drosophila species show no substantial distortion of Mendelian segregation and no appreciable male recombination. These results do not support the theories that meiotic drive alleles of large effect are often fixed within species and that transposable genetic elements cause speciation.

scholarly journals Meiotic Nuclear Architecture in Distinct Mole Vole Hybrids with Robertsonian Translocations: Chromosome Chains, Stretched Centromeres, and Distorted Recombination

2020 ◽  
Vol 21 (20) ◽  
pp. 7630
Author(s):  
Sergey Matveevsky ◽  
Artemii Tretiakov ◽  
Anna Kashintsova ◽  
Irina Bakloushinskaya ◽  
Oxana Kolomiets
Keyword(s):  
Interspecific Hybrids ◽  
Nuclear Architecture ◽  
Late Pachytene ◽  
Robertsonian Translocations ◽  
Structure And Dynamics ◽  
Chromosome Synapsis ◽  
Mole Vole ◽  
Chromosomal Variability ◽  
Chromosomal Territories ◽  
First Time

Genome functioning in hybrids faces inconsistency. This mismatch is manifested clearly in meiosis during chromosome synapsis and recombination. Species with chromosomal variability can be a model for exploring genomic battles with high visibility due to the use of advanced immunocytochemical methods. We studied synaptonemal complexes (SC) and prophase I processes in 44-chromosome intraspecific (Ellobius tancrei × E. tancrei) and interspecific (Ellobius talpinus × E. tancrei) hybrid mole voles heterozygous for 10 Robertsonian translocations. The same pachytene failures were found for both types of hybrids. In the intraspecific hybrid, the chains were visible in the pachytene stage, then 10 closed SC trivalents formed in the late pachytene and diplotene stage. In the interspecific hybrid, as a rule, SC trivalents composed the SC chains and rarely could form closed configurations. Metacentrics involved with SC trivalents had stretched centromeres in interspecific hybrids. Linkage between neighboring SC trivalents was maintained by stretched centromeric regions of acrocentrics. This centromeric plasticity in structure and dynamics of SC trivalents was found for the first time. We assume that stretched centromeres were a marker of altered nuclear architecture in heterozygotes due to differences in the ancestral chromosomal territories of the parental species. Restructuring of the intranuclear organization and meiotic disturbances can contribute to the sterility of interspecific hybrids, and lead to the reproductive isolation of studied species.

scholarly journals Meiotic nuclear architecture in distinct mole vole hybrids with Robertsonian translocations: chromosome chains, stretched centromeres, and distorted recombination

2020 ◽  
Author(s):  
Sergey Matveevsky ◽  
Artemii Tretiakov ◽  
Irina Bakloushinskaya ◽  
Anna Kashintsova ◽  
Oxana Kolomiets
Keyword(s):  
Interspecific Hybrids ◽  
Nuclear Architecture ◽  
Late Pachytene ◽  
Robertsonian Translocations ◽  
Prophase I ◽  
Chromosome Synapsis ◽  
Chromosome Attachment ◽  
Mole Vole ◽  
Chromosomal Variability ◽  
Chromosomal Territories

AbstractGenome functioning in hybrids faces inconsistency. This mismatch is manifested clearly in meiosis during chromosome synapsis and recombination. Species with chromosomal variability can be a model for exploring genomic battles with high visibility due to the use of advanced immunocytochemical methods. We studied synaptonemal complexes (SC) and prophase I processes in 44-chromosome intraspecific (Ellobius tancrei × E. tancrei) and interspecific (Ellobius talpinus × E. tancrei) hybrid mole voles heterozygous for 10 Robertsonian translocations. The same pachytene failures were found for both types of hybrids. In the intraspecific hybrid, the chains were visible in the pachytene stage, then 10 closed SC trivalents formed in the late pachytene and diplotene stage. In the interspecific hybrid, as a rule, SC trivalents composed the SC chains and rarely could form closed configurations. Metacentrics involved with SC trivalents had stretched centromeres in interspecific hybrids. Linkage between neighboring SC trivalents was maintained by stretched centromeric regions of acrocentrics. This centromeric plasticity in structure and dynamics of SC trivalents was found for the first time. We assume that stretched centromeres were a marker of altered nuclear architecture in heterozygotes due to differences in the ancestral chromosomal territories of the parental species. Restructuring of the intranuclear organization and meiotic disturbances can contribute to the sterility of interspecific hybrids, and lead to the reproductive isolation of studied species.Author summaryMeiosis is essential for sexual reproduction to produce haploid gametes. Prophase I represents a crucial meiotic stage because key processes such as chromosomal pairing, synapsis and desynapsis, recombination, and transcriptional silencing occur at this time. Alterations in each of these processes can activate meiotic checkpoints and lead to the elimination of meiocytes. Here we have shown that two groups of experimental hybrids, intraspecific and interspecific—which were heterozygous for 10 identical Robertsonian translocations—had pachytene irregularities and reduced recombination. However, intraspecific and interspecific hybrids exhibited different patterns of synaptonemal complex (SC) trivalent behavior. In the former, open SC trivalents comprised SC chains due to heterosynapsis of short arms of acrocentrics in early and mid-pachytene and were then able to form 2–4 and even 7 and 10 closed SC trivalents in the late pachytene and diplotene stages. In the second mole voles, SC trivalents had stretched centromeres of the metacentrics, and chains of SC trivalents were formed due to stretched centromeres of acrocentrics. Such compounds could not lead to the formation of separate closed SC trivalents. The distant ancestral points of chromosome attachment with a nuclear envelope in the heterozygous nuclei probably lead to stretching of SC trivalents and their centromeric regions, which can be regarded as an indicator of the reorganization of the intranuclear chromatin landscape. These abnormalities, which were revealed in in prophase I, contribute to a decrease the fertility of intraspecific mole voles and promote the sterility of interspecific mole voles.

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