2 edition of Reproductive isolation between races of the grasshopper, Podisma pedestris. found in the catalog.
Reproductive isolation between races of the grasshopper, Podisma pedestris.
P. L. Mason
Thesis (Ph.D), University of East Anglia, School of Biological Sciences, 1988.
Background. It has long been recognised that the evolution and maintenance of new species requires reproductive isolation, whereby barriers to interbreeding prevent gene flow between incipient species [ 1, 2 ]. The nature of these barriers, and their evolution, has been a central focus of speciation by: 2. Hybridization, where distinguishable populations meet and interbreed resulting in hybrid offspring, is useful for understanding the mechanisms involved in the evolution of reproductive isolation. Hybridization can range from interactions with near-complete reproductive isolation, to stable zones, to complete by: 7.
have been responsible for the non-viability of hybrids between two chromosomal races of the grasshopper Podisma pedestris. At the other extreme, pre-zygotic isolation in snails is apparently caused by single mutations that change the direction of the coiling, making copulation impossible. In the corn borer, ethological isolation is caused by. Asymmetric reproductive isolation between terminal forms of the salamander ring species Ensatina eschscholtzii revealed by fine-scale genetic analysis of a hybrid zone A sex-chromosome hybrid zone in the grasshopper Podisma pedestris (Orthoptera: Acrididae). The genetic structure of a hybrid zone between two chromosome races of the.
Post-copulatory selection based on sperm karyotype has, for example, been reported in two chromosomal races of the alpine grasshopper Podisma pedestris. After mating with males of both chromosomal races, females were preferentially fertilized by males of their own karyotype (homogamy: Hewitt, Mason & Nichols, ).Author: Sonja H. Sbilordo, Sonja H. Sbilordo, Oliver Y. Martin, Georg Ribi. Abstract. Three species of burdock (Arctium lappa, A. tomentosum, and A. minus; Asteraceae), which commonly occur in sympatry in Central Europe, are thought to hybridize frequently, hence raising questions about their surveyed mixed, monotypic, and/or single plant stands of these species in Central Germany to assess their extent of hybridization and introgression, and also Cited by: 6.
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Reproductive isolation between races of the grasshopper, Podisma pedestris. (Thesis) Mason PL. Publisher: University of East Anglia  Metadata Source: The British Library Type: Thesis.
Abstract. No abstract supplied. Menu. Formats. Abstract. EThOS. About. About Europe PMC Cited by: 1. Reproductive isolation between races of the grasshopper, Podisma pedestris. Author: Mason, Philip Leslie. ISNI: Awarding Body: University of East Anglia Current Institution: University of East Anglia Date of Award: Availability of Full Text.
Genetic incompatibilities between two races of the grasshopper Podisma pedestris, which differ by a Robertsonian fusion involving the sex chromosome, have been investigated.
Samples were taken from five sites in a transect across the hybrid zone between two chromosomal races of the grasshopper Podisma pedestris. Crosses were set Reproductive isolation between races of the grasshopper between insects from the same population, and between populations spanning the zone, and the early viability of the offspring was by: Homogamy in a hybrid zone in the Alpine grasshopper Podisma pedestris.
Females of the grasshopper Podisima pedestris were collected from the middle of a hybrid zone between two chromosomal races in the Alpes Maritimes. They had already mated in the field, and could therefore lay fertilised eggs in the laboratory.
FIGURE The chromosomal cline in the grasshopper Podisma pedestris. (A) An adult male. (B) Chromosome pairs at male meiosis; the cross-like structures are chiasmata that correspond to recombination events (see Fig.
The arrow shows a fusion between the X. M Westerman, N H Barton and G M Hewitt, Differences in DNA content between two chromosomal races of the grasshopper Podisma pedestris, Heredity, /hdy, 58, 2.
There is a narrow hybrid zone between two chromosomal races of the grasshopper Podisma pedestris in the French Alps. There are no gross differences in habitat across the. Grasshoppers, Acrididae, Podisma sapporensis, chromosome races, experimental crossing, zygotic barrier Abstract.
Experimental hybridization of X0 and XY chromosome races of the brachypterous grasshopper P. sapporensis did not reveal pre-zygotic reproductive isolation. However, a partial zygotic barrier was found between the X0-standard race from Shimo-Cited by: 6. General Introduction, Rationale and Key Questions.
isolated from other such groups”. Reproductive isolation is thus the sine qua non of a good species. The reproductive barriers that separate members of different species are divided into inviability in hybrids between two chromosomal races of the grasshopper Podisma pedestris (Barton. Population structure and the shape of a chromosomal cline between two races of Podisma pedestris (Orthoptera: Acrididae).
The cytogenetic characteristics of the grasshopper Podisma sapporensis (two races 2n = 23♂ X0/XX and 2n = 22♂ neo-XY/neo-XX) were analysed Author: Beata Grzywacz, Beata Grzywacz, Haruki Tatsuta, Haruki Tatsuta, Alexander G. Bugrov, Alexander G. Individual virgin females of two races of Podisma pedestris were mated sequentially with a male of each race in one or other reciprocal orders, giving four types of double matings.
Individual virgin females of two races of Podisma pedestris were mated sequentially with a male of each race in one or other reciprocal orders, giving four types of double matings. The embryos were karyotyped to determine the extent of each male's by: between a sex chromosome and an autosome, and chromosome rearrangements.
The fixation levels of inversions varied depending on geographic regions. No hybrid population is known implying that a strong reproductive isolation system exists in hybrids between the different chromosomal races. Hybrid zone, unimodal: a hybrid zone in which intermediate hybrid genotypes predominate (see also Ref.
Unimodality should be considered the null hypothesis, against which the more complex hypothesis of bimodality can be tested. A flat hybrid zone is intermediate between bimodal and unimodal zones (see also Ref.
3).Cited by: In the present paper we study pre and postmating reproductive isolation of two populations of the red-winged grasshopper O. germanica in relation to conservation measures such as the possible introduction of individuals from one location to a declining population or to Cited by: Determining the taxonomic status of the Mexican gray wolf and the red wolf requires an understanding of the contemporary meanings of “species” and “subspecies” and access to relevant genomic, ecological, and morphological data.
The goal of this chapter is to provide background in all of these topics, with a strong focus on those considerations directly relevant to wolf : Division on Earth, Board on Agriculture. Post-mating interactions between the reproductive traits and gametes of mating individuals and among their genes within zygotes are invariably complex, providing multiple opportunities for reproduction to go awry.
These interactions have the potential to act as barriers to gene flow between species, and may be important in the process of by: 2. No hybrid population is known implying that a strong reproductive isolation system exists in hybrids between the different chromosomal races. The probable reasons for the purity of X0 and neo-XY chromosome races and high chromosome polymorphism in contact zones between chromosomal subraces are by: 6.
Bimodal hybrid zones and speciation. Podisma pedestris chromosomal races (grasshopper) Little deviation from HW: Although there is a broad correlation between overall reproductive isolation and Nei’s D, similar to that shown in Drosophila. Coyne J.A. Orr by: This insight can be traced back to a key early paper in Heredity (Hewitt, ), in which he reports 3 years of work, mapping the geographical course of a hybrid zone between two chromosomal races of the grasshopper Podisma pedestris in the southern French Alps and surrounding mountains.
It is remarkable, on rereading it today, to see the germs of the key ideas that subsequently flowered through his Cited by: 1.Another common chromosomal sex-determination system has only one sex chromosome, the X (e.g. in the model organism Caenorhabditis elegans).In this so-called X/O system, females have two X chromosomes, whereas males only have idea is that X/O sex determination is the outcome of the degeneration, and ultimately the loss, of the Y chromosome (see Box 1), with the X/O system thus Cited by: 9.