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- Hillier, Ladeana W, et al.
(författare)
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Sequence and comparative analysis of the chicken genome provide unique perspectives on vertebrate evolution
- 2004
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Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 432:7018, s. 695-716
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Tidskriftsartikel (refereegranskat)abstract
- We present here a draft genome sequence of the red jungle fowl, Gallus gallus. Because the chicken is a modern descendant of the dinosaurs and the first non-mammalian amniote to have its genome sequenced, the draft sequence of its genome--composed of approximately one billion base pairs of sequence and an estimated 20,000-23,000 genes--provides a new perspective on vertebrate genome evolution, while also improving the annotation of mammalian genomes. For example, the evolutionary distance between chicken and human provides high specificity in detecting functional elements, both non-coding and coding. Notably, many conserved non-coding sequences are far from genes and cannot be assigned to defined functional classes. In coding regions the evolutionary dynamics of protein domains and orthologous groups illustrate processes that distinguish the lineages leading to birds and mammals. The distinctive properties of avian microchromosomes, together with the inferred patterns of conserved synteny, provide additional insights into vertebrate chromosome architecture.
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- Scott, David R, et al.
(författare)
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Use of human papillomavirus DNA testing to compare equivocal cervical cytologic interpretations in the United States, Scandinavia, and the United Kingdom
- 2002
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Ingår i: Cancer. - : John Wiley and Sons Inc.. - 1097-0142 .- 0008-543X. ; 96:1, s. 14-20
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Human papillomavirus (HPV) DNA testing may be useful in clarifying equivocal cervical cytologic interpretations. One application might be to standardize the meaning of equivocal interpretations from laboratories in various regions. Because international differences may be particularly marked, international comparisons of emerging data will require clear translations of "equivocal" and similar terms. METHODS: To perform a three-country comparison, the authors selected a morphologically diverse set of 188 conventional Papanicolaou tests initially classified as "squamous atypia" from a study of more than 20,000 women in Portland, Oregon (1989-1990). Previously, five U.S. expert cytopathologists independently interpreted the slides with screening cytotechnologists' marks in place. For this comparison, one British and two Scandinavian reviewers involved in HPV research reviewed the slides after original marks had been removed. The authors compared all eight reviewers' classifications of negative, equivocal, or abnormal in a series of pairwise comparisons using the kappa statistic. They then compared cytologic interpretations with HPV DNA testing. RESULTS: Oncogenic HPV DNA detection was significantly associated with increasingly abnormal interpretations for each reader. The British reader tended to rate tests as more abnormal than the American pathologists did, whereas the Scandinavians tended to rate tests as more normal. Reference to the HPV DNA standard clarified the tendency of readers to render systematically more or less severe interpretations. For example, the Scandinavian cytologists discounted subtle (often HPV-associated) changes in favor of cytologic certainty, making HPV triage of equivocal tests less applicable there. CONCLUSIONS: International research on cytopathology, particularly on the possible uses of HPV DNA testing, will require calibration of local cytologic definitions.
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- Ekblom, Robert, 1976-
(författare)
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Immunoecology of the Great Snipe (Gallinago media) : Mate Choice, MHC Variation, and Humoral Immunocompetence in a Lekking Bird
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- At the centre of the vertebrate immune system is a group of proteins called MHC (major histocompatibility complex) molecules. These function in self – non self recognition and activation of the immune defence against intruding parasites and pathogens. In this thesis I have investigated individual variation in MHC class II genes and antibody producing ability in relation to ecology and behaviour in the great snipe (Gallinago media), a lekking bird, breeding in northern Europe. There was much variation in the MHC genes of the great snipe and the sequence data show that balancing selection has been acting on these genes. I found genetic differentiation in the MHC between two separate geographic regions of the great snipe distribution. Furthermore, this structure was more pronounced than that previously found in neutral genetic markers, suggesting that different selection pressures (possibly resulting from variation in parasitic fauna) are acting in these different regions. The birds produced specific antibodies following injection with two novel antigens. Males that were chosen as mates, had higher antibody titers than their neighbouring males, suggesting that this ability may be important in female mate choice. Such choice could give the offspring an enhanced immune system or could favour females directly by avoidance of sexually transmitted diseases. Females choosing to mate with a male having a different set of MHC genes than their own could give the offspring immune system the ability to react to a wide range of parasites. No such mate choice could, however, be found in the great snipe. Instead, females preferred males with certain MHC alleles, irrespective of their own MHC type. If those alleles confer resistance to parasites currently prevailing in the population, such resistance would be inherited by the offspring, thereby enhancing their fitness.
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