THE SALIVARY GLAND CHROMOSOMES OF SIX SPECIES IN THE IIIS-1 GROUP OF PROSIMULIUM ROUB. (DIPTERA: SIMULIIDAE)

1966 ◽  
Vol 44 (4) ◽  
pp. 677-701 ◽  
Author(s):  
P. O. Ottonen
Keyword(s):  
Salivary Gland ◽  
Sex Chromosomes ◽  
North American ◽  
Sex Chromosome ◽  
Chromosomal Polymorphism ◽  
Population Data ◽  
North American Species

The morphology of the salivary gland chromosomes of six North American species of the genus Prosimulium was studied. Five of these species, P. caudatum Shewell, P. dicum Dyar and Shannon, P. "Y", P. magnum D. and S., and P. multidentatum Twinn, share inversion IIIS-1; P. "X" has standard IIIS, but is related to P. caudatum through inversion IIS-10.From an analysis of interspecific rearrangements and intraspecific chromosomal polymorphism, a phylogeny was constructed for this IIIS-1 group of species. The more extensive population data for P. magnum revealed an incipient split of this species into two types of populations, differing in details of the sex chromosomes, and in distribution. Hybrid populations are rare. Sex chromosome polytypism was also observed in P. dicum, P. "Y", and P. multidentatum.

Sibling species of the blackfly Prosimulium onychodactylum (Simuliidae, Diptera): a salivary gland chromosome study

1983 ◽  
Vol 61 (12) ◽  
pp. 2816-2835 ◽  
Author(s):  
Lester J. Newman
Keyword(s):  
Salivary Gland ◽  
Reproductive Isolation ◽  
Sibling Species ◽  
Chromosome Pairing ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Homologous Pairing ◽  
Chromosome Markers ◽  
Chromosome Arm ◽  
Backcross Hybrids

Larvae of the morphospecies Prosimulium onychodactylum collected from two streams in northern Oregon are divided into 11 sibling species based on fixed and polymorphic inversions. The sibling species have differentiated sex chromosomes; each sibling species falls into one of two groups based on the chromosome arm which carries the sex chromosome markers. Males exhibit lack of homologous pairing or inversion heterzygosity and females have complete chromosome pairing or inversion homozygosity. There is a succession of sibling species which mature in the streams from January through September. Mature larvae of each sibling species are present for about 6 weeks; some are synchronic while others are allochronic. Some of the sibling species occur in the same stream and others are in different streams. Sibling species which are both synchronic and sympatric appear to be reproductively isolated. Reproductive isolation may not be complete for sibling species which are normally allopatric or allochronic; small numbers of F1 and backcross hybrids were found between some of these sibling species. The division of the morphospecies into sibling species was also observed in collections from Washington through northern California.

The genus Ectemnia (Diptera: Simuliidae): taxonomy, polytene chromosomes, new species, and phylogeny

1997 ◽  
Vol 75 (11) ◽  
pp. 1896-1915 ◽  
Author(s):  
J. K. Moulton ◽  
P. H. Adler
Keyword(s):  
New Species ◽  
Coastal Plain ◽  
North American ◽  
Sex Chromosome ◽  
Polytene Chromosomes ◽  
North American Species ◽  
Immature Stages ◽  
Two New Species ◽  
Southeastern Coastal Plain

The genus Ectemnia Enderlein consists of four North American species, two of which are described as new. The two previously described species, E. invenusta and E. taeniatifrons, are primarily northern in distribution and their immature stages occupy rocky rivers. The two new species, E. primaeva and E. reclusa, occur in the southeastern Coastal Plain; their immature stages inhabit blackwater swamp streams and sandy rivers. Keys are provided for larvae, pupae, and adults. The polytene chromosomes of all species are analyzed in detail. Seven fixed inversions, 10 unshared autosomal polymorphisms, two centromere-band expressions, and five sex-chromosome systems are recognized among the four species. At least 10 synapomorphies indicate that the genus is monophyletic. Phylogenetically, Ectemnia is in a clade with Metacnephia and Simulium.

THE SALIVARY GLAND CHROMOSOMES OF THREE NORTH AMERICAN SPECIES OF TWINNIA (DIPTERA: SIMULIIDAE)

1966 ◽  
Vol 44 (5) ◽  
pp. 937-943 ◽  
Author(s):  
K. Rothfels ◽  
Margaret Freeman
Keyword(s):  
Salivary Gland ◽  
North American ◽  
North American Species ◽  
Centromere Region ◽  
Standard Sequence ◽  
Chromosome Iii

The salivary gland chromosomes of the three known North American species of Twinnia Stone and Jamnback are described, and compared with those of Prosimulium Roubaud. Twinnia tibblesi S. and J. has the standard arm association and the standard sequence in IS, II, IIIL. It differs from standard in inversions IL-1, IIIS-2,3, and a repatterning of the centromere region of chromosome III. Twinnia nova (Dyar and Shannon) and T. biclavata Shewell share these T. tibblesi traits and, in addition, have, in common, inversion IIIL-1 and a whole arm interchange giving the combinations IIL, IIIL and IIS, IIIS. Twinnia biclavata differs from T. nova by inversion IS-1 and a nucleolar shift. Both are good species. Evidence is presented that Twinnia is phylogenetically intermediate between Gymnopais Stone and the subgenus Helodon Enderlein of Prosimulium.

Chironomus blaylocki sp. n. and C. bifurcatus sp. n., North American species near the base of the decorus-group (Diptera: Chironomidae)

Zootaxa ◽  
2009 ◽  
Vol 2023 (1) ◽  
pp. 28-46 ◽  
Author(s):  
WOLFGANG WUELKER ◽  
JON MARTIN ◽  
IYA I. KIKNADZE ◽  
JAMES E. SUBLETTE ◽  
SUSANNE MICHIELS
Keyword(s):  
Salivary Gland ◽  
New Species ◽  
North American ◽  
Polytene Chromosomes ◽  
Distinct Species ◽  
North American Species ◽  
Larval Morphology ◽  
Banding Patterns ◽  
Group Species

Two species of the cytologically defined Chironomus decorus-group, C. bifurcatus sp. n. and C. blaylocki sp. n., are described on the basis of their salivary gland polytene chromosomes and larval morphology, with the associated male and pupa of C. bifurcatus and the putative male of C. blaylocki included as paratypes. The banding patterns of the salivary gland chromosomes indicate that these species are near the base of the cytologically defined decorus-group. The cytology and adults of these new species are compared with those of a number of other undescribed North American decorus-group species to demonstrate that they are distinct species.

Mitotic analysis of the North American white sturgeon, Acipenser transmontanus Richardson (Pisces, Acipenseridae), a fish with a very high chromosome number

Genome ◽  
1998 ◽  
Vol 41 (2) ◽  
pp. 266-271 ◽  
Author(s):  
A L Eenennaam ◽  
J D Murray ◽  
J F Medrano
Keyword(s):  
Chromosome Number ◽  
North American ◽  
Sex Chromosome ◽  
Chromosomal Polymorphism ◽  
White Sturgeon ◽  
Acipenser Transmontanus ◽  
Banding Technique ◽  
Supernumerary Chromosomes ◽  
C Banding ◽  
The North

The average chromosome number of the North American white sturgeon, Acipenser transmontanus Richardson, was found to be 271 ± 2.5 (ranging from 265 to 276). This number is significantly higher than previous estimates for this species. A representative karyotype was found to consist of 132 meta- and submeta-centric chromosomes, 44 acrocentric chromosomes, and 98 microchromosomes. An improved C-banding technique revealed variation (2-7) between animals in the number of entirely heterochromatic metacentric chromosomes. These heterochromatic chromosomes may represent supernumerary chromosomes. There was no cytogenetic evidence of a heteromorphic sex chromosome pair or any sex-related chromosomal polymorphism in either sex of this species.Key words: C-banding, fish, karyotype, supernumerary chromosomes, white sturgeon.

scholarly journals Differential Gene Expression between Fungal Mating Types Is Associated with Sequence Degeneration

2020 ◽  
Vol 12 (4) ◽  
pp. 243-258 ◽  
Author(s):  
Wen-Juan Ma ◽  
Fantin Carpentier ◽  
Tatiana Giraud ◽  
Michael E Hood
Keyword(s):  
Differential Expression ◽  
Differentially Expressed Genes ◽  
Mating Type ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Gc Content ◽  
Differentially Expressed ◽  
Mating Types ◽  
Sexual Antagonism ◽  
Recombination Suppression

Abstract Degenerative mutations in non-recombining regions, such as in sex chromosomes, may lead to differential expression between alleles if mutations occur stochastically in one or the other allele. Reduced allelic expression due to degeneration has indeed been suggested to occur in various sex-chromosome systems. However, whether an association occurs between specific signatures of degeneration and differential expression between alleles has not been extensively tested, and sexual antagonism can also cause differential expression on sex chromosomes. The anther-smut fungus Microbotryum lychnidis-dioicae is ideal for testing associations between specific degenerative signatures and differential expression because 1) there are multiple evolutionary strata on the mating-type chromosomes, reflecting successive recombination suppression linked to mating-type loci; 2) separate haploid cultures of opposite mating types help identify differential expression between alleles; and 3) there is no sexual antagonism as a confounding factor accounting for differential expression. We found that differentially expressed genes were enriched in the four oldest evolutionary strata compared with other genomic compartments, and that, within compartments, several signatures of sequence degeneration were greater for differentially expressed than non-differentially expressed genes. Two particular degenerative signatures were significantly associated with lower expression levels within differentially expressed allele pairs: upstream insertion of transposable elements and mutations truncating the protein length. Other degenerative mutations associated with differential expression included nonsynonymous substitutions and altered intron or GC content. The association between differential expression and allele degeneration is relevant for a broad range of taxa where mating compatibility or sex is determined by genes located in large regions where recombination is suppressed.

Evolution of Sex Chromosome Heteromorphy in Geographic Populations of the Japanese Tago’s Brown Frog Complex

2021 ◽  
pp. 1-9
Author(s):  
Chiao Kuwana ◽  
Hiroyuki Fujita ◽  
Masataka Tagami ◽  
Takanori Matsuo ◽  
Ikuo Miura
Keyword(s):  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Mitochondrial Gene ◽  
Population Level ◽  
Chromosome 7 ◽  
Geographic Population ◽  
Geographic Populations ◽  
Western Japan ◽  
Brown Frog ◽  
Eastern Japan

The sex chromosomes of most anuran amphibians are characterized by homomorphy in both sexes, and evolution to heteromorphy rarely occurs at the species or geographic population level. Here, we report sex chromosome heteromorphy in geographic populations of the Japanese Tago’s brown frog complex (2n = 26), comprising Rana sakuraii and R. tagoi. The sex chromosomes of R. sakuraii from the populations in western Japan were homomorphic in both sexes, whereas chromosome 7 from the populations in eastern Japan were heteromorphic in males. Chromosome 7 of R. tagoi, which is distributed close to R. sakuraii in eastern Japan, was highly similar in morphology to the Y chromosome of R. sakuraii. Based on this and on mitochondrial gene sequence analysis, we hypothesize that in the R. sakuraii populations from eastern Japan the XY heteromorphic sex chromosome system was established by the introduction of chromosome 7 from R. tagoi via interspecies hybridization. In contrast, chromosome 13 of R. tagoi from the 2 large islands in western Japan, Shikoku and Kyushu, showed a heteromorphic pattern of constitutive heterochromatin distribution in males, while this pattern was homomorphic in females. Our study reveals that sex chromosome heteromorphy evolved independently at the geographic lineage level in this species complex.

Sign in / Sign up

Export Citation Format

Share Document