Chromosomal polymorphisms in the pitcher-plant mosquito, Wyeomyia smithii

Moeur, John E.; Istock, Conrad A.

doi:10.1007/bf00286330

Cited by 10 publications

(3 citation statements)

References 39 publications

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“…The underlying linkage map (Figure 1) shows three linkage groups, consistent with the haploid number of chromosomes in W. smithii (Moeur and Istock 1982), and shows the sex locus on the shortest chromosome, as in other mosquitoes (Clements 1992, p. 2). In Figures 2 and 3, we mark nine QTL for CPP and four QTL for SOD.…”

Section: Discussionmentioning

confidence: 55%

Quantitative Trait Loci Associated with Photoperiodic Response and Stage of Diapause in the Pitcher-Plant Mosquito, Wyeomyia smithii

Mathias¹,

Jacky²,

Bradshaw

et al. 2007

Genetics

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A wide variety of temperate animals rely on length of day (photoperiodism) to anticipate and prepare for changing seasons by regulating the timing of development, reproduction, dormancy, and migration. Although the molecular basis of circadian rhythms regulating daily activities is well defined, the molecular basis for the photoperiodic regulation of seasonal activities is largely unknown. We use geographic variation in the photoperiodic control of diapause in the pitcher-plant mosquito Wyeomyia smithii to create the first QTL map of photoperiodism in any animal. For critical photoperiod (CPP), we detect QTL that are unique, a QTL that is sex linked, QTL that overlap with QTL for stage of diapause (SOD), and a QTL that interacts epistatically with the circadian rhythm gene, timeless. Results presented here confirm earlier studies concluding that CPP is under directional selection over the climatic gradient of North America and that the evolution of CPP is genetically correlated with SOD. Despite epistasis between timeless and a QTL for CPP, timeless is not located within any detectable QTL, indicating that it plays an ancillary role in the evolution of photoperiodism in W. smithii. Finally, we highlight one region of the genome that includes loci contributing to CPP, SOD, and hormonal regulation of development.T HE annual change in day length at temperate latitudes provides a highly reliable indicator of future seasonal events and a wide variety of organisms use day length (photoperiod) to time their development, reproduction, dormancy, and migration. Concordance between individual photoperiodic response and local climate is an essential component of fitness for animals living in the temperate zone (Bradshaw et al. 2004), and modification of photoperiodic response is an important adaptation of animals during range expansion (Danilevskii 1965;Cooke 1977;Tauber et al. 1986;Danks 1987;Lounibos et al. 2003) or when confronted with rapid climate change (Bradshaw and Holzapfel 2001a, 2006). Photoperiodism provides an ecologically relevant, highly heritable trait whose adaptive significance in a temperate seasonal environment is not questioned. Length of the favorable or growing season in North America decreases with increasing latitude (Bradshaw 1976). Consequently, the optimal time to enter diapause advances to an earlier day in the year and the day length used to switch from active development to diapause [hereafter, the critical photoperiod (CPP)] is positively correlated with latitude and altitude among a wide variety of temperate arthropods (Danilevskii 1965;Taylor and Spalding 1986;Danks 1987). The consistent genetic change in photoperiodic response over geographic and climatic gradients provides one of the most robust examples of repeated adaptive evolution in nature.Although much progress has been made in identifying the genetic components of the circadian clock regulating daily activities, the molecular basis of the photoperiodic timer regulating seasonal activities is conspicuously absent from the ...

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Section: Discussionmentioning

confidence: 55%

Quantitative Trait Loci Associated with Photoperiodic Response and Stage of Diapause in the Pitcher-Plant Mosquito, Wyeomyia smithii

Mathias¹,

Jacky²,

Bradshaw

et al. 2007

Genetics

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“…Prior to the 1980s, it was even speculated that the chromosomes of anopheline mosquitoes were simply more permissive or tolerant of inversions than the chromosomes of culicines (Rai & Hartberg, 1975). However, by the late 1970s, cytogenetic techniques had improved sufficiently for researchers to document abundant inversions in the culicine genera Culex (Tewfik & Barr, 1976), Wyeomyia (Moeur & Istock, 1982), Orthopodomyia (Munstermann et al. , 1985) and Sabethes (Munstermann & Marchi, 1986).…”

Section: Introductionmentioning

confidence: 99%

Evidence of multiple chromosomal inversions in Aedes aegypti formosus from Senegal

Bernhardt

Blair

Sylla

et al. 2009

Insect Molecular Biology

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Chromosomal inversions are prevalent in mosquito species but polytene chromosomes are difficult to prepare and visualize in members of the tribe Aedinii and thus there exists only indirect evidence of inversions. We constructed an F(1) intercross family using a P(1) female from a laboratory strain of Aedes aegypti aegypti (Aaa) and a P(1) male Aedes aegypti formosus (Aaf) from a strain collected from south-eastern Senegal. Recombination rates in the F(2) offspring were severely reduced and genotype ratios suggested a deleterious recessive allele on chromosome 3. The F(2) linkage map was incongruent in most respects with the established map for Aaa. Furthermore, no increased recombination was detected in F(5) offspring. Recombination rates and gene order were consistent with the presence in Aaf of at least four large inversions on chromosome 1, a single small inversion on chromosome 2 and three inversions on chromosome 3.

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“…Further laboratory studies examined genetic effects on life history characteristics in crosses between mosquitoes from populations from northern temperate and subtropical climates (Istock 1982). In addition, Moeur and Istock (1982) described extensive chromosomal inversion polymorphism in a population and Istock and Weisburg (1987) described among-population polymorphism at two electrophoretic loci and suggested that the pattern of variation at each locus was governed by natural selection. Scheiner and Istock (1991) also conducted an artificial selection experiment to investigate how that the phenotypic correlation between development time and diapause tendency constrains the direction and magnitude of life history evolution in this species.…”

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confidence: 99%

Resolution of Respect: Conrad Alan Istock (1936–2023)

Orzack,

Bell,

Bronstein

et al. 2024

Bulletin Ecologic Soc America

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along with one sister and two brothers. During childhood, Conrad was shy, but he sang in the church choir along with his mother, took up playing the violin, which became a lifelong passion, and was an enthusiastic Boy Scout, eventually becoming an Eagle Scout. He loved the outdoors and his troop's camping trips further stimulated his lifelong fascination with nature. Conrad matriculated at Wayne University (now Wayne State University) in Detroit in the fall of 1954. His circuitous path through college makes his career as a biologist seem far from inevitable. He first enrolled Resolutions of Respect 2 Bulletin of the Ecological Society of America, 105(2) Article e02129in the College of Engineering. In the winter of 1956, he transferred to the pre-education curriculum in the College of Liberal Arts and then in the winter of 1957 to the College of Education as a "science" major. He intended to be a high school teacher. It was not until the spring of 1956, his fourth semester in college, that he took "General Biology," which was his first course in biology. He took one biology course in each of the following four semesters. As he entered his last year of college in the fall of 1958, only five of the forty-three courses he had taken were in biology. His last year was different, as six of his nine courses were biology. We describe below what sparked this change. In his last semester, he transferred back to the College of Liberal Arts and became a biology major. He graduated in June 1959 with a B.A.Conrad's undergraduate years must have been especially stimulating for two reasons. The first is that the Biology Department at Wayne served students having a great diversity of educational goals. This is reflected in the courses it offered, which included Bacteriology, Comparative Anatomy, Endocrinology, Histology, Immunology, Invertebrate Zoology, and Ornithology, as well as courses such as Antiseptics and Disinfectants, Microbiology for Contract Nurses, Industrial Microbiology, and Scientific Aspects of Disease Control for students entering healthcare and public-health professions. The second reason is that the number of matriculated students increased

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Chromosomal polymorphisms in the pitcher-plant mosquito, Wyeomyia smithii

Cited by 10 publications

References 39 publications

Quantitative Trait Loci Associated with Photoperiodic Response and Stage of Diapause in the Pitcher-Plant Mosquito, Wyeomyia smithii

Quantitative Trait Loci Associated with Photoperiodic Response and Stage of Diapause in the Pitcher-Plant Mosquito, Wyeomyia smithii

Evidence of multiple chromosomal inversions in Aedes aegypti formosus from Senegal

Resolution of Respect: Conrad Alan Istock (1936–2023)

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