The population structure of Simulium vittatum (Zett.): the IIIL-1 and IS-7 sibling species

1981 ◽  
Vol 59 (10) ◽  
pp. 1857-1883 ◽  
Author(s):  
Klaus Rothfels ◽  
David Featherston
Keyword(s):  
United States ◽  
Population Structure ◽  
Salivary Gland ◽  
Sibling Species ◽  
Sex Chromosome ◽  
Geographic Pattern ◽  
Northeastern United States ◽  
Simulium Vittatum ◽  
Cytological Characteristics ◽  
Wide Zone

This paper describes two sibling species in Simulium vittatum (Zett.) on the basis of their salivary gland chromosomes. The IIIL-1 sibling is characterized by a Y chromosome carrying the IIIL-1 inversion; the IS-7 sibling is characterized by the IS-7 X chromosome. The basic banding sequences are identical in the two sibling species. The siblings differ however in the relative frequencies of standard and inverted sequences for a number of autosomal polymorphisms that they share. Standard sequences are predominant in the IIIL-1 sibling and inverted sequences in the IS-7 type. The IIIL-1 sibling is distributed from the Atlantic, south to the Gulf of Mexico and west to the Saskatchewan–Alberta border. The IS-7 sibling ranges from the Atlantic to Alaska, but so far has not been found south of Pennsylvania. The sibling species are sympatric over a wide zone extending through parts of Quebec, Ontario, and northeastern United States via Michigan, Wisconsin, and Minnesota to Saskatchewan and Alberta. It is argued that the two sibling species originated in the region of the present sympatry. Evidence for this conclusion derives from the geographic pattern of sex chromosome and autosome polymorphism in North America and from cytological characteristics of certain extraterritorial populations (Iceland).

Sex chromosome polymorphism in the Simulium tuberosum complex (Lundström) (Diptera: Simuliidae)

1984 ◽  
Vol 62 (4) ◽  
pp. 647-658 ◽  
Author(s):  
G. F. Mason
Keyword(s):  
United States ◽  
Sibling Species ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Distinct Species ◽  
Chromosome Polymorphism ◽  
Northeastern United States ◽  
Primary Zone ◽  
Heteromorphic Sex Chromosomes ◽  
Unusual Chromosome

These studies on the Simulium tuberosum complex have revealed the presence of a number of closely related sibling species which are distinguished by the banding pattern on their sex chromosomes. Collections were made over wide geographic areas of North America and the distributions of the various types found were recorded. Included are areas in northeastern United States with sites at which a number of the sibling species are sympatric. At these sites the separation of one taxa from another is not clear and a number of intra- and inter-sibling sex chromosome polymorphisms were detected. Included in these polymorphs were larvae with unusual chromosome combinations, including females with heteromorphic sex chromosomes. Arguments are made for some of the divisions as distinct species and for sex chromosome polymorphism in others. Based on the evidence of the geographic distribution, it is suggested that the area of sympatry in which polymorphism in all of the division of the complex was found is a primary zone of speciation.

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.

scholarly journals Population Structure of the Lyme Borreliosis Spirochete Borrelia burgdorferi in the Western Black-Legged Tick (Ixodes pacificus) in Northern California

2009 ◽  
Vol 75 (22) ◽  
pp. 7243-7252 ◽  
Author(s):  
Yvette A. Girard ◽  
Bridgit Travinsky ◽  
Anna Schotthoefer ◽  
Natalia Fedorova ◽  
Rebecca J. Eisen ◽  
...  
Keyword(s):  
United States ◽  
Population Structure ◽  
Borrelia Burgdorferi ◽  
Lyme Borreliosis ◽  
Intergenic Spacer ◽  
Reservoir Host ◽  
23S Rrna ◽  
Northeastern United States ◽  
Ixodes Pacificus ◽  
Mendocino County

ABSTRACT Factors potentially contributing to the lower incidence of Lyme borreliosis (LB) in the far-western than in the northeastern United States include tick host-seeking behavior resulting in fewer human tick encounters, lower densities of Borrelia burgdorferi-infected vector ticks in peridomestic environments, and genetic variation among B. burgdorferi spirochetes to which humans are exposed. We determined the population structure of B. burgdorferi in over 200 infected nymphs of the primary bridging vector to humans, Ixodes pacificus, collected in Mendocino County, CA. This was accomplished by sequence typing the spirochete lipoprotein ospC and the 16S-23S rRNA intergenic spacer (IGS). Thirteen ospC alleles belonging to 12 genotypes were found in California, and the two most abundant, ospC genotypes H3 and E3, have not been detected in ticks in the Northeast. The most prevalent ospC and IGS biallelic profile in the population, found in about 22% of ticks, was a new B. burgdorferi strain defined by ospC genotype H3. Eight of the most common ospC genotypes in the northeastern United States, including genotypes I and K that are associated with disseminated human infections, were absent in Mendocino County nymphs. ospC H3 was associated with hardwood-dominated habitats where western gray squirrels, the reservoir host, are commonly infected with LB spirochetes. The differences in B. burgdorferi population structure in California ticks compared to the Northeast emphasize the need for a greater understanding of the genetic diversity of spirochetes infecting California LB patients.

Monitoring air quality in class I wilderness areas of the northeastern United States using lichens and bryophytes

2016 ◽  
Author(s):  
Alison C. Dibble ◽  
James W. Hinds ◽  
Ralph Perron ◽  
Natalie Cleavitt ◽  
Richard L. Poirot ◽  
...  
Keyword(s):  
United States ◽  
Air Quality ◽  
Class I ◽  
Northeastern United States ◽  
Wilderness Areas
Sign in / Sign up

Export Citation Format

Share Document