Crossing Experiments Supporting the Specific Status of Anopheles maculatus Chromosomal Form K

SUMMARYHybrid parasites may have an increased transmission potential and higher virulence compared to their parental species. Consequently, hybrid detection is critical for disease control. Previous crossing experiments showed that hybrid schistosome eggs have distinct morphotypes. We therefore compared the performance of egg morphology with molecular markers with regard to detecting hybridization in schistosomes. We studied the morphology of 303 terminal-spined eggs, originating from 19 individuals inhabiting a hybrid zone with natural crosses between the human parasite Schistosoma haematobium and the livestock parasite Schistosoma bovis in Senegal. The egg sizes showed a high variability and ranged between 92·4 and 176·4 µm in length and between 35·7 and 93·0 µm in width. No distinct morphotypes were found and all eggs resembled, to varying extent, the typical S. haematobium egg type. However, molecular analyses on the same eggs clearly showed the presence of two distinct partial mitochondrial cox1 profiles, namely S. bovis and S. haematobium, and only a single nuclear ITS rDNA profile (S. haematobium). Therefore, in these particular crosses, egg morphology appears not a good indicator of hybrid ancestry. We conclude by discussing strengths and limitations of molecular methods to detect hybrids in the context of high-throughput screening of field samples.

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Wolbachia infection in Argentinean populations of Anastrepha fraterculus sp1: preliminary evidence of sex ratio distortion by one of two strains

10.1101/738500 ◽

2019 ◽

Cited By ~ 1

Author(s):

CA Conte ◽

DF Segura ◽

FH Milla ◽

AA Augustinos ◽

JL Cladera ◽

...

Keyword(s):

Sex Ratio ◽

Insect Pests ◽

Wolbachia Infection ◽

Larval Survival ◽

Preliminary Evidence ◽

Wild Populations ◽

Crossing Experiments ◽

Anastrepha Fraterculus ◽

Male Killing ◽

Filarial Nematodes

ABSTRACTBackgroundWolbachia, one of the most abundant taxa of intracellular Alphaproteobacteria, is widespread among arthropods and filarial nematodes. The presence of these maternally inherited bacteria is associated with modifications of host fitness, including a variety of reproductive abnormalities, such as cytoplasmic incompatibility, thelytokous parthenogenesis, host feminization and male-killing. Wolbachia has attracted much interest for its role in biological, ecological and evolutionary processes as well as for its potential use in novel and environmentally-friendly strategies for the control of insect pests and disease vectors including a major agricultural pest, the South American fruit fly, Anastrepha fraterculus Wiedemann (Diptera: Tephritidae).ResultsWe used wsp, 16S rRNA and a multilocus sequence typing (MLST) scheme including gatB, coxA, hcpA, fbpA, and ftsZ genes to detect and characterize the Wolbachia infection in laboratory strains and wild populations of A. fraterculus from Argentina. Wolbachia was found in all A. fraterculus individuals studied. Nucleotide sequences analysis of wsp gene allowed the identification of two Wolbachia nucleotide variants (named wAfraCast1_A and wAfraCast2_A). After the analysis of 76 individuals, a high prevalence of the wAfraCast2_A variant was found both, in laboratory (82%) and wild populations (95%). MLST analysis identified both Wolbachia genetic variants as sequence type 13. Phylogenetic analysis of concatenated MLST datasets clustered wAfraCast1/2_A in the supergroup A. Paired-crossing experiments among single infected laboratory strains showed a phenotype specifically associated to wAfraCast1_A that includes slight detrimental effects on larval survival, a female-biased sex ratio; suggesting the induction of male-killing phenomena, and a decreased proportion of females producing descendants that appears attributable to the lack of sperm in their spermathecae.ConclusionsWe detected and characterized at the molecular level two wsp gene sequence variants of Wolbachia both in laboratory and wild populations of A. fraterculus sp.1 from Argentina. Crossing experiments on singly-infected A. fraterculus strains showed evidence of a male killing-like mechanism potentially associated to the wAfraCast1_A - A. fraterculus interactions. Further mating experiments including antibiotic treatments and the analysis of early and late immature stages of descendants will contribute to our understanding of the phenotypes elicited by the Wolbachia variant wAfraCast1_A in A. fraterculus sp.1.

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Selection of Pairings Reaching Evenly Across the Data (SPREAD): A simple algorithm to design maximally informative fully crossed mating experiments

10.1101/009720 ◽

2014 ◽

Author(s):

Kolea Zimmerman ◽

Daniel Levitis ◽

Ethan Addicott ◽

Anne Pringle

Keyword(s):

Nearest Neighbor ◽

Simple Algorithm ◽

Two Dimensional ◽

Neighbor Distance ◽

Crossing Experiments ◽

The Mean ◽

Parameter Values ◽

Selection Of ◽

Novel Algorithm ◽

Trait Space

We present a novel algorithm for the design of crossing experiments. The algorithm identifies a set of individuals (a ?crossing-set?) from a larger pool of potential crossing-sets by maximizing the diversity of traits of interest, for example, maximizing the range of genetic and geographic distances between individuals included in the crossing-set. To calculate diversity, we use the mean nearest neighbor distance of crosses plotted in trait space. We implement our algorithm on a real dataset ofNeurospora crassastrains, using the genetic and geographic distances between potential crosses as a two-dimensional trait space. In simulated mating experiments, crossing-sets selected by our algorithm provide better estimates of underlying parameter values than randomly chosen crossing-sets.

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Geographical Differentiation in a Japanese Stream-Breeding Frog, Buergeria buergeri, Elucidated by Morphometric Analyses and Crossing Experiments.

ZOOLOGICAL SCIENCE ◽

10.2108/zsj.15.615 ◽

1998 ◽

Vol 15 (4) ◽

pp. 615-622 ◽

Cited By ~ 1

Author(s):

Hiroaki Ueda ◽

Yoshinori Hasegawa ◽

Junsuke Marunouchi

Keyword(s):

Crossing Experiments ◽

Geographical Differentiation ◽

Morphometric Analyses

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Mendel’s pea crosses: varieties, traits and statistics

Hereditas ◽

10.1186/s41065-019-0111-y ◽

2019 ◽

Vol 156 (1) ◽

Author(s):

T. H. Noel Ellis ◽

Julie M. I. Hofer ◽

Martin T. Swain ◽

Peter J. van Dijk

Keyword(s):

Statistical Analysis ◽

Normal Distribution ◽

Standard Normal Distribution ◽

Data Sets ◽

Crossing Experiments ◽

Independent Variables ◽

F2 Population ◽

A Value ◽

Segregation Ratios ◽

Standard Normal

Abstract A controversy arose over Mendel’s pea crossing experiments after the statistician R.A. Fisher proposed how these may have been performed and criticised Mendel’s interpretation of his data. Here we re-examine Mendel’s experiments and investigate Fisher’s statistical criticisms of bias. We describe pea varieties available in Mendel’s time and show that these could readily provide all the material Mendel needed for his experiments; the characters he chose to follow were clearly described in catalogues at the time. The combination of character states available in these varieties, together with Eichling’s report of crosses Mendel performed, suggest that two of his F3 progeny test experiments may have involved the same F2 population, and therefore that these data should not be treated as independent variables in statistical analysis of Mendel’s data. A comprehensive re-examination of Mendel’s segregation ratios does not support previous suggestions that they differ remarkably from expectation. The χ2 values for his segregation ratios sum to a value close to the expectation and there is no deficiency of extreme segregation ratios. Overall the χ values for Mendel’s segregation ratios deviate slightly from the standard normal distribution; this is probably because of the variance associated with phenotypic rather than genotypic ratios and because Mendel excluded some data sets with small numbers of progeny, where he noted the ratios “deviate not insignificantly” from expectation.

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Calculation of Line Broadening Cross Sections for Level Crossing Experiments in Alkali-Rare Gas Systems

Zeitschrift für Naturforschung A ◽

10.1515/zna-1974-0409 ◽

1974 ◽

Vol 29 (4) ◽

pp. 605-609

Author(s):

B. Grosswendt

Keyword(s):

Cross Section ◽

Cross Sections ◽

Rare Gas ◽

Atomic Interaction ◽

Cross Section Data ◽

Line Broadening ◽

Crossing Experiments ◽

Level Crossing ◽

Section Data ◽

Frame Work

Using a simple approximation for the theoretical atomic interaction constants cross section data for level crossing and Hanle-effect line broadening experiments in Rb, Mg+ and Ca+ rare gas systems could be derived. It is shown that in the Rb system the interaction C6R-6 is predominant and that the results are little influenced by dipole-quadrupole and repulsive interactions in the frame work of the Lindholm-Foley-Hindmarsh theory.

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Anopheles (Cellia) rampae n. sp., alias chromosomal form K of the Oriental Maculatus Group (Diptera: Culicidae) in Southeast Asia

Zootaxa ◽

10.11646/zootaxa.2810.1.5 ◽

2011 ◽

Vol 2810 (1) ◽

pp. 47 ◽

Cited By ~ 12

Author(s):

PRADYA SOMBOON ◽

DAMRONGPAN THONGWAT ◽

RALPH E. HARBACH

Keyword(s):

Southeast Asia ◽

Sibling Species ◽

Male Genitalia ◽

Instar Larva ◽

Fourth Instar ◽

Fourth Instar Larva ◽

Chromosomal Form ◽

Oriental Region ◽

As Species

Chromosomal form K (also known as species K) of the Anopheles maculatus group of sibling species in the Oriental Region is diagnosed and formally named An. (Cellia) rampae Harbach & Somboon, n. sp. The male genitalia, pupa and fourth-instar larva are illustrated and information is provided on the morphology, systematics, bionomics and distribution of the species.

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Genetics: the centre of science

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1966.0019 ◽

1966 ◽

Vol 164 (995) ◽

pp. 154-166 ◽

Cited By ~ 4

Keyword(s):

General Principle ◽

Pollen Parent ◽

Seed Parent ◽

Crossing Experiments ◽

Basic Principles ◽

Isaac Newton ◽

Large Numbers ◽

The Difference

It is not often possible to pinpoint the origin of a whole new branch of science accurately in time and place, because, as Isaac Newton said, there are usually so many precursors on whose shoulders the successor stands and is thereby able to see further than they. But genetics is an exception, for it owes its origin to one man, Gregor Johann Mendel, who expounded its basic principles at Brno on 8 February and 8 March 1865. If a precursor is a man who, at an earlier date, makes a discovery which his successor is able to expand into a general principle of universal validity, Mendel had no precursors. There were not wanting breeders who hybridized plants: Joseph Gottlieb Koelreuter, Carl Friedrich von Gaertner, and William Herbert, to mention only the chief names, but what they were studying was not really basic genetics at all. They wanted to know if sterility in a hybrid is the fault of the pollen-parent or the seed-parent, whether either parent could be held responsible for the characters of different specified regions of the plant, or which had prepotency over the characters of the hybrid. The parent races that they chose for their crossing experiments were either different species, or varieties differing in large numbers of characters, and the results which they obtained were chaotic, inconstant, and contradictory, and led to no general principles at all. This was the difference between previous attempts to study heredity, and the Mendelian revolution that resulted in genetics.

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Frequency of cross-fertilization in the human malaria parasitePlasmodium falciparum

Parasitology ◽

10.1017/s003118200007935x ◽

1993 ◽

Vol 107 (1) ◽

pp. 11-18 ◽

Cited By ~ 71

Author(s):

L. C. Ranford-Cartwright ◽

P. Balfe ◽

R. Carter ◽

D. Walliker

Keyword(s):

Malaria Parasite ◽

Anopheles Stephensi ◽

Random Mating ◽

Crossing Experiments ◽

Chain Reaction ◽

Human Malaria Parasite ◽

Human Malaria ◽

Polymerase Chain ◽

Cross Fertilization

SummaryTwo clones of the human malaria parasitePlasmodium falciparum, denoted 3D7 and HB3, were grownin vitrounder conditions permitting the development of gametocytes. The two clones differ in their allelic forms of two antigen genes MSP1 and MSP2. The alleles can be distinguished as size differences of polymerase chain reaction (PCR) amplified fragments of repetitive regions of each gene. Mosquitoes (Anopheles stephensi) were fed on a mixture of these gametocytes. A total of 128 oocysts was isolated from the midguts of infected mosquitoes from 9 crossing experiments between the clones. DNA extracted from these oocysts was amplified by PCR. Oocysts which contained both alleles of each gene (MSP1 and MSP2) had developed from heterozygotes produced by cross-fertilization events between 3D7 and HB3 gametes. The remaining oocysts contained single alleles of each gene, in parent clone combinations, and these had developed from homozygotes formed by self-fertilizations. The results suggest that gametes in the original mixture fed to mosquitoes had undergone random mating.

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