8,489 research outputs found

    Variation in actual relationship among descendants of inbred individuals

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    In previous analyses, the variation in actual, or realized, relationship has been derived as a function of map length of chromosomes and type of relationship, the variation being greater the shorter the total chromosome length and the coefficient of variation being greater the more distant the relationship. Here, the results are extended to allow for the relatives' ancestor being inbred. Inbreeding of a parent reduces variation in actual relationship among its offspring, by an amount that depends on the inbreeding level and the type of mating that led to that level. For descendants of full-sibs, the variation is reduced in later generations, but for descendants of half-sibs, it is increased

    Convergence of eigenvalues for a highly non-self-adjoint differential operator

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    In this paper we study a family of operators dependent on a small parameter ϵ>0\epsilon > 0, which arise in a problem in fluid mechanics. We show that the spectra of these operators converge to N as ϵ0\epsilon \to 0, even though, for fixed ϵ>0\epsilon > 0, the eigenvalue asymptotics are quadratic.Comment: 16 page

    Cysteine proteinase C1A paralog profiles correspond with phylogenetic lineages of pathogenic piroplasmids

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    Piroplasmid parasites comprising of Babesia, Theileria, and Cytauxzoon are transmitted by ticks to farm and pet animals and have a significant impact on livestock industries and animal health in tropical and subtropical regions worldwide. In addition, diverse Babesia spp. infect humans as opportunistic hosts. Molecular phylogeny has demonstrated at least six piroplasmid lineages exemplified by B. microti, B. duncani, C. felis, T. equi, Theileria sensu stricto (T. annulata, T. parva, and T. orientalis) and Babesia sensu stricto (B. bovis, B. bigemina, and B. ovis). C1A cysteine-proteinases (C1A-Cp) are papain-like enzymes implicated in pathogenic and vital steps of the parasite life cycle such as nutrition and host cell egress. An expansion of C1A-Cp of T. annulata and T. parva with respect to B. bovis and B. ovis was previously described. In the present work, C1A-Cp paralogs were identified in available genomes of species pertaining to each piroplasmid lineage. Phylogenetic analysis revealed eight C1A-Cp groups. The profile of C1A-Cp paralogs across these groups corroborates and defines the existence of six piroplasmid lineages. C. felis, T. equi and Theileria s.s. each showed characteristic expansions into extensive families of C1A-Cp paralogs in two of the eight groups. Underlying gene duplications have occurred as independent unique evolutionary events that allow distinguishing these three piroplasmid lineages. We hypothesize that C1A-Cp paralog families may be associated with the advent of the schizont stage. Differences in the invertebrate tick host specificity and/or mode of transmission in piroplasmid lineages might also be associated with the observed C1A-Cp paralog profiles

    A case of pleural mesothelioma with effusive-constrictive pericarditis.

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    A case report is presented of pleural mesothelioma with simultaneous development of benign effusive-constrictive pericarditis

    Highly syntenic and yet divergent: a tale of two Theilerias

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    The published genomic sequences of the two major host-transforming Theileria species of cattle represent a rich resource of information that has allowed novel bioinformatic and experimental studies into these important apicomplexan parasites. Since their publication in 2005, the genomes of T. annulata and T. parva have been utilised for a diverse range of applications, ranging from candidate antigen discovery to the identification of genetic markers for population analysis. This has led to advancements in the quest for a sub-unit vaccine, while providing a greater understanding of variation among parasite populations in the field. The unique ability of these Theileria species to induce host cell transformation is the subject of considerable scientific interest and the availability of full genomic sequences has provided new insights into this area of research. This article reviews the data underlying published comparative analyses, focussing on the general features of gene expression, the major Tpr/Tar multi-copy gene family and a re-examination of the predicted macroschizont secretome. Codon usage between the Theileria species is reviewed in detail, as this underpins ongoing comparative studies investigating selection at the intra- and inter-species level. The TashAT/TpshAT family of genes, conserved between T. annulata and T. parva, encodes products targeted to the host nucleus and has been implicated in contributing to the transformed bovine phenotype. Species-specific expansion and diversification at this critical locus is discussed with reference to the availability, in the near future, of genomic datasets which are based on non-transforming Theileria species

    Fractal Characterizations of MAX Statistical Distribution in Genetic Association Studies

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    Two non-integer parameters are defined for MAX statistics, which are maxima of dd simpler test statistics. The first parameter, dMAXd_{MAX}, is the fractional number of tests, representing the equivalent numbers of independent tests in MAX. If the dd tests are dependent, dMAX<dd_{MAX} < d. The second parameter is the fractional degrees of freedom kk of the chi-square distribution χk2\chi^2_k that fits the MAX null distribution. These two parameters, dMAXd_{MAX} and kk, can be independently defined, and kk can be non-integer even if dMAXd_{MAX} is an integer. We illustrate these two parameters using the example of MAX2 and MAX3 statistics in genetic case-control studies. We speculate that kk is related to the amount of ambiguity of the model inferred by the test. In the case-control genetic association, tests with low kk (e.g. k=1k=1) are able to provide definitive information about the disease model, as versus tests with high kk (e.g. k=2k=2) that are completely uncertain about the disease model. Similar to Heisenberg's uncertain principle, the ability to infer disease model and the ability to detect significant association may not be simultaneously optimized, and kk seems to measure the level of their balance
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