THE SALIVARY GLAND CHROMOSOMES OF SIX CLOSELY RELATED BLACK FLIES NEAR EUSIMULIUM CONGAREENARUM (DIPTERA: SIMULIIDAE)

1967 ◽  
Vol 45 (4) ◽  
pp. 377-396 ◽  
Author(s):  
Robert W. Dunbar
Keyword(s):  
Salivary Gland ◽  
Related Species ◽  
Chromosome Banding ◽  
Black Flies ◽  
Distinct Form ◽  
Closely Related Species ◽  
Banding Patterns ◽  
Natural Group ◽  
Y Chromosomes ◽  
Giant Chromosome

The salivary gland chromosomes of nearctic black flies which form a natural group in Eusimulium close to E. congareenarum were analyzed in detail. Comparisons of their giant chromosome banding patterns disclosed six cytological segregates in two subgroups; subgroup A, with E. innocens, E. anatinum, E. congareenarum, and a cytologically distinct form near the latter designated E. congareenarum 'b'; subgroup B, with E. excisum and E. rivuli. Within each subgroup closely related species differ at least by (1) two or three interspecific inversions, (2) the intraspecific specific inversions present, and (3) the details of the X and Y chromosomes. The differences between the subgroups include (1) the position of the nucleolus, (2) the identity of the sex chromosomes as either the first or third pair, and (3) about 15 interspecific inversions between E. congareenarum and E. excisum, the most closely related species from either subgroup. The phylogenetic interrelationships have been traced by means of the interspecific inversions.

scholarly journals Unique structure and positive selection promote the rapid divergence of Drosophila Y chromosomes

2021 ◽  
Author(s):  
Ching-Ho Chang ◽  
Lauren E. Gregory ◽  
Kathleen E. Gordon ◽  
Colin D. Meiklejohn ◽  
Amanda M. Larracuente
Keyword(s):  
Positive Selection ◽  
Y Chromosome ◽  
Related Species ◽  
De Novo ◽  
Gene Families ◽  
Chromosome Organization ◽  
End Joining ◽  
Sexual Antagonism ◽  
Closely Related Species ◽  
Y Chromosomes

AbstractY chromosomes across diverse species convergently evolve a gene-poor, heterochromatic organization enriched for duplicated genes, LTR retrotransposable elements, and satellite DNA. Sexual antagonism and a loss of recombination play major roles in the degeneration of young Y chromosomes. However, the processes shaping the evolution of mature, already degenerated Y chromosomes are less well-understood. Because Y chromosomes evolve rapidly, comparisons between closely related species are particularly useful. We generated de novo long read assemblies complemented with cytological validation to reveal Y chromosome organization in three closely related species of the Drosophila simulans complex, which diverged only 250,000 years ago and share >98% sequence identity. We find these Y chromosomes are divergent in their organization and repetitive DNA composition and discover new Y-linked gene families whose evolution is driven by both positive selection and gene conversion. These Y chromosomes are also enriched for large deletions, suggesting that the repair of double-strand breaks on Y chromosomes may be biased toward microhomology-mediated end joining over canonical non-homologous end-joining. We propose that this repair mechanism generally contributes to the convergent evolution of Y chromosome organization.

HYBRIDIZATION BETWEEN THE NEARCTIC ANOPHELES PUNCTIPENNIS AND THE PALEARCTIC ANOPHELES ATROPARVUS

1977 ◽  
Vol 19 (2) ◽  
pp. 265-270
Author(s):  
Richard D. Kreutzer
Keyword(s):  
Salivary Gland ◽  
Chromosome Banding ◽  
Interspecific Crosses ◽  
Inverted Region ◽  
Banding Patterns ◽  
X Chromosomes ◽  
Chromosomal Homology ◽  
Anopheles Atroparvus ◽  
Palearctic Species ◽  
High Level

Interspecific crosses were made between the Palearctic species Anopheles atroparvus Van Thiel and the Nearctic species A. punctipennis Say. Except for most of the X chromosomes, an inverted region in 3R, and band intensity differences the salivary gland chromosome banding patterns are the same in both species. Despite this high level of chromosomal homology very little synapsis of identically banded regions was observed in hybrid complements. This asynapsis and the fact that no adults were produced from either the cross or the reciprocal indicate that there are significant genetic differences between the species.

scholarly journals Unique structure and positive selection promote the rapid divergence of Drosophila Y chromosomes

eLife ◽  
2022 ◽  
Vol 11 ◽  
Author(s):  
Ching-Ho Chang ◽  
Lauren E Gregory ◽  
Kathleen E Gordon ◽  
Colin D Meiklejohn ◽  
Amanda M Larracuente
Keyword(s):  
Positive Selection ◽  
Y Chromosome ◽  
Related Species ◽  
De Novo ◽  
Gene Families ◽  
Chromosome Organization ◽  
End Joining ◽  
Sexual Antagonism ◽  
Closely Related Species ◽  
Y Chromosomes

Y chromosomes across diverse species convergently evolve a gene-poor, heterochromatic organization enriched for duplicated genes, LTR retrotransposons, and satellite DNA. Sexual antagonism and a loss of recombination play major roles in the degeneration of young Y chromosomes. However, the processes shaping the evolution of mature, already degenerated Y chromosomes are less well-understood. Because Y chromosomes evolve rapidly, comparisons between closely related species are particularly useful. We generated de novo long read assemblies complemented with cytological validation to reveal Y chromosome organization in three closely related species of the Drosophila simulans complex, which diverged only 250,000 years ago and share >98% sequence identity. We find these Y chromosomes are divergent in their organization and repetitive DNA composition and discover new Y-linked gene families whose evolution is driven by both positive selection and gene conversion. These Y chromosomes are also enriched for large deletions, suggesting that the repair of double-strand breaks on Y chromosomes may be biased toward microhomology-mediated end joining over canonical non-homologous end-joining. We propose that this repair mechanism contributes to the convergent evolution of Y chromosome organization across organisms.

THE EVOLUTIONARY HISTORY OF DROSOPHILA BUZZATII. III. CYTOGENETIC RELATIONSHIPS BETWEEN TWO SIBLING SPECIES OF THE BUZZATII CLUSTER

Genetics ◽  
1982 ◽  
Vol 101 (3-4) ◽  
pp. 503-518 ◽  
Author(s):  
A Ruiz ◽  
A Fontdevila ◽  
M Wasserman
Keyword(s):  
Salivary Gland ◽  
Sibling Species ◽  
Related Species ◽  
Evolutionary History ◽  
South American ◽  
Closely Related Species ◽  
Drosophila Buzzatii ◽  
Repleta Group ◽  
Chromosomal Data ◽  
History Of

ABSTRACT Drosophila buzzatii has been found sympatric in Argentina with a closely-related sibling species, D. serido. The biogeographical, reproductive and chromosomal data allow us to combine these species into an evolutionary unit, the buzzatii cluster. Salivary gland chromosomes also have been used to determine their phylogenetic relationships with other closely related species, showing that the buzzatii cluster species share two inversions—2d  2 and 2s  6—with the species of the martensis cluster. Both clusters arose from South American populations of the ancestor of the mulleri complex, and we propose to include D. buzzatii and D. serido in the mulleri complex of the repleta group.

Three New Ontario Black Flies of the Genus Prosimulium (Diptera: Simuliidae): Part I. Descriptions, Morphological Comparisons with Related Species, and Distribution

1958 ◽  
Vol 90 (12) ◽  
pp. 697-719 ◽  
Author(s):  
P. D. Syme ◽  
D. M. Davies
Keyword(s):  
Salivary Gland ◽  
Banding Pattern ◽  
Related Species ◽  
External Environment ◽  
Black Flies ◽  
Eastern Canada ◽  
Phylogenetic Relations ◽  
Morphological Detail

Chromosonial studies have elucidated phylogenetic relations in Drosophila (White, 1954), culicids (Jucci, 1952) and chironomids (Bauer, 1936, 1945). Since it appeared promising to apply this approach to the Simuliidae, Rothfels and Dunbar (1953) began a cytological survey of the black flies of eastern Canada during the summer of 1951. They found that in this group the giant salivary gland chromosomes provided “a wealth of descriptive morphological detail in their number and gross morphology, in the characteristics of expanded centromere regions, in the location of specific nucleolar sites, in the degree of pairing of constituents, and in the ultimate discernible banding pattern…. Since these features are not functionally related to the external environment, the confusing effects of convergence are minimized, resemblances may be taken to indicate relation, and grouping is possible according to natural affinities” (Rothfels and Dunbar, 1953).

Polytene chromosome mapping in Ceratitis capitata (Diptera: Tephritidae)

Genome ◽  
1987 ◽  
Vol 29 (4) ◽  
pp. 598-611 ◽  
Author(s):  
D. G. Bedo
Keyword(s):  
Salivary Gland ◽  
Polytene Chromosome ◽  
Chromosome Banding ◽  
Mitotic Chromosome ◽  
Ceratitis Capitata ◽  
Polytene Chromosomes ◽  
Chromosome Mapping ◽  
Banding Patterns ◽  
Homologous Chromosomes ◽  
Characteristic Features

Polytene chromosome reference maps of the five autosomes of Ceratitis capitata from male pupal orbital bristle trichogen cells are presented and a correlation is established between two of them and the two largest of the five autosomes in the haploid mitotic complement. Characteristic features of each chromosome are described identifying areas that are difficult to analyze and noting the existence of common alternative band expression. A quantitative analysis of the mitotic karyotype of C. capitata indicates that the two smallest autosome pairs cannot be reliably distinguished. This may present problems with future attempts to establish homologies between the remaining mitotic and polytene chromosomes. A comparison of polytene chromosome banding patterns from salivary gland and trichogen cells failed to find any homologous regions, or even to identify homologous chromosomes. The banding differences are not explained by variation in puffing patterns, heterochromatin expression, or polyteny levels, but appear to reflect fundamental differences in banding patterns of the chromosomes in each tissue. Key words: Ceratitis capitata, polytene chromosome map, mitotic chromosome measurements.

scholarly journals Rapid Identification of Polyhydroxyalkanoate Accumulating Members of Bacillales Using Internal Primers for phaC Gene of Bacillus megaterium

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Pramoda Kumar Nayak ◽  
Ajeet Kumar Mohanty ◽  
Teja Gaonkar ◽  
Ashwani Kumar ◽  
Saroj N. Bhosle ◽  
...  
Keyword(s):  
Bacillus Megaterium ◽  
Related Species ◽  
Rapid Identification ◽  
Rt Pcr ◽  
Closely Related Species ◽  
Banding Patterns ◽  
Phac Gene ◽  
Polyhydroxyalkanoate Synthase ◽  
Pcr Method ◽  
Respective Species

Bacillus megaterium is gaining recognition as an experimental model and biotechnologically important microorganism. Recently, descriptions of new strains of B. megaterium and closely related species isolated from diverse habitats have increased. Therefore, its identification requires several tests in combination which is usually time consuming and difficult to do. We propose using the uniqueness of the polyhydroxyalkanoate synthase C gene of B. megaterium in designing primers that amplify the 0.9 kb region of the phaC for its identification. The PCR method was optimized to amplify 0.9 kb region of phaC gene. After optimization of the PCR reaction, two methods were investigated in detail. Method I gave an amplification of a single band of 0.9 kb only in B. megaterium and was demonstrated by several strains of B. megaterium isolated from different habitats. The use of Method I did not result in the amplification of the phaC gene with other members of Bacillales. The specificity for identification of B. megaterium was confirmed using sequencing of amplicon and RT-PCR. Method II showed multiple banding patterns of nonspecific amplicons among polyhydroxyalkanoate accumulating members of Bacillales unique to the respective species. These methods are rapid and specific for the identification of polyhydroxyalkanoate accumulating B. megaterium and members of Bacillales.

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